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Background: Early treatment discontinuation will have a negative effect on a drug's benefit-risk profile if discontinuation occurs earlier in time than the positive effects of treatment. This non-persistence of therapy has been associated with an increased risk of adverse health outcomes.Objective: The aim of this study was to explore relationships between patient characteristics and reasons for and time to discontinuation of rimonabant therapy, focusing on psychiatric events, because these were the main safety concerns for rimonabant.Methods: A modified prescription-event monitoring (M-PEM) study was conducted for rimonabant. Descriptive statistics were used to describe the patient population. Rate ratios with 95% confidence intervals (CIs) were calculated to explore associations between patient characteristics and selected categories of reasons for stopping (RfS). Median times to discontinuation were compared using the Mann-Whitney U test.Results: The cohort comprised 10,011 users of rimonabant, three of which were excluded from this analysis because of missing age or sex. A total of 7204 patients (72.0%) stopped using rimonabant (median observation time 323 days, interquartile range: 279-371 days). In addition, patients with a history of psychiatric illness were more likely to discontinue rimonabant therapy early for all reasons, but most pronounced due to psychiatric events (rate ratio 1.79; 95% CI 1.54, 2.09) than those without a history of psychiatric illness. In contrast, the rates of discontinuation due to lack of effectiveness, any clinical events and psychiatric events in patients with cardiovascular disease, type 2 diabetes mellitus, dyslipidaemia or hypertension tended to be lower (not all being significant) than those without. For patients who discontinued treatment due to lack of effectiveness, the median time to discontinuation was significantly shorter for patients with a history of psychiatric illness, compared with patients without a history of psychiatric illness (86 vs 97 days, p = 0.03). For patients discontinuing treatment due to psychiatric events, the difference in median time to discontinuation was also 11 days (64 vs 75 days, p = 0.38), although not statistically significant. For patients stopping due to any clinical event, median time to discontinuation was comparable for patients with and without a history of psychiatric illness (61 vs 63 days, p = 0.90).Conclusions: In this study, reasons for and time to discontinuation were associated with patient characteristics such as medical history. Patients discontinued treatment because of psychiatric events early after starting. In general, identification and characterization of early discontinuers, and increasing the understanding of reasons for stopping, may help healthcare professionals to develop targeted interventions to further improve treatment compliance, thereby optimizing treatment benefits and drug safety. [ABSTRACT FROM AUTHOR]

Background: In Europe, Direct Healthcare Professional Communications (DHPCs) are important tools to inform healthcare professionals of serious, new drug safety issues. However, this tool has not always been successful in effectively communicating the desired actions to healthcare professionals.Objective: The aim of this study was to explore healthcare providers' experiences and their preferences for improvement of risk communication, comparing views of general practitioners (GPs), internists, community pharmacists and hospital pharmacists.Methods: A questionnaire was developed and pilot tested to assess experiences and preferences of Dutch healthcare professionals with DHPCs. The questionnaire and two reminders were sent to a random sample of 3488 GPs, internists and community and hospital pharmacists in the Netherlands. Descriptive statistics were used to describe demographic characteristics of the respondents. Chi squares, ANOVAs and the Wilcoxon signed rank test were used, when appropriate, to compare healthcare professional groups.Results: The overall response rate was 34% (N = 1141, ranging from 24% for internists to 46% for community pharmacists). Healthcare providers trusted safety information more when provided by the Dutch Medicines Evaluation Board (MEB) than by the pharmaceutical industry. This was more the case for GPs than for the other healthcare professionals. Respondents preferred safety information to be issued by the MEB, the Dutch Pharmacovigilance Center or their own professional associations. The preferred alternative channels of drug safety information were e-mail, medical journals and electronic prescribing systems.Conclusions: Safety information of drugs does not always reach healthcare professionals through DHPCs. To improve current risk communication of drug safety issues, alternative and/or additional methods of risk communication should be developed using electronic methods and medical journals. Moreover, (additional) risk communication coming from an independent source such as the MEB should be considered. Special effort is needed to reach GPs. [ABSTRACT FROM AUTHOR]

Background: Relevant safety signals in the EU are regularly communicated in so-called 'Direct Healthcare Professional Communications' (DHPCs) or European Medicines Agency (EMA) press releases. Trends of a decrease in the use of rosiglitazone following regulatory safety warnings have been described in the US. In the EU, however, relatively little is known about dispensing patterns following DHPCs or other safety signals such as EMA press releases.Objective: The objective of this study was to analyse trends in dispensing patterns of rosiglitazone and pioglitazone following DHPCs and EMA press releases in the EU member state, the Netherlands.Methods: Data for this study were obtained from the PHARMO Record Linking System, which includes drug dispensing records from community pharmacies of approximately 2.5 million individuals in the Netherlands. Over the period 1998-2008 an auto-regressive, integrated, moving average model (ARIMA) was fitted. The DHPC letters or EMA press releases were used as determinants. Adjustments were made for publication of certain literature. Stratification was performed for dispensings prescribed by general practitioners (GPs) and those prescribed by specialists.Results: For rosiglitazone, four EMA press releases and two DHPCs were issued; for pioglitazone, one DHPC was issued. The number of rosiglitazone dispensings prescribed by GPs decreased significantly after publication of DHPCs and EMA press releases concerning the risk of macular oedema and risk of fractures (both p-values 0.001). The number of rosiglitazone dispensings decreased statistically significantly after publication of EMA press releases 2 and 3 concerning cardiovascular risks but not for EMA press release 4. Adjustment for certain publications in the literature reduced the effect of communicated safety issues on the proportion of dispensings.Conclusions: Although it is difficult to disentangle the effect of DHPCs and EMA press releases from the effect of reports published in the literature, our results suggest that prescribers may react to such safety communications. [ABSTRACT FROM AUTHOR]

Background: After market approval, new serious safety issues are regularly identified for drugs that lead to regulatory action to inform healthcare professionals. However, the effectiveness of these safety-related regulatory actions is under question. We currently lack a comprehensive overview of the effects of these drug safety warnings on clinical practice to resolve the debate about their effectiveness.Objective: The aim of this systematic review is to provide an overview of studies that assessed the impact of safety warnings.Study Selection: A systematic search was performed for articles assessing the impact of Direct Healthcare Professional Communications or 'Dear Doctor' letters, Black Box Warnings and Public Health Advisories on clinical behaviour published between January 1996 and January 2010. The following variables were extracted: publication year, country, name of the drug, safety issue, specific safety warning (Direct Healthcare Professional Communication/Black Box Warning/Public Health Advisory), effect (intended/unintended) of the safety warning, outcome measure and study design. Papers were checked for several quality aspects. Study data were summarized using descriptive analyses.Results: A total of 50 articles were identified. Two articles assessed two different drugs and were therefore counted twice (n = 52). Thirty-three articles described the impact of safety warnings issued for three drugs and drug groups, i.e. third-generation oral contraceptives, cisapride and selective serotonin reuptake inhibitors. The remaining 19 articles described a broad variety of 14 drugs and drug groups. Twenty-five studies applied an interrupted time series design, 23 a controlled or uncontrolled before/after design, and four articles applied both. None of the articles could rule out the influence of confounding factors. The intended effects were reported in 18 (72%) of the 25 before/after analyses, whereas only 11 (41%) of the 27 interrupted time series analyses reported an impact. Only two (8%) of the before/after analyses against 11 (41%) of the interrupted time series analyses reported mixed impacts. When unintended effects were assessed in case of selective serotonin reuptake inhibitors and third-generation oral contraceptives, these were almost always present: in 19 of 22 and 4 of 5 articles, respectively. Our review shows that safety-related regulatory action can have some impact on clinical practice but firm conclusions are difficult to draw. Evidence is primarily based on three drugs and drug groups. Almost half of the studies had inadequate before/after designs and the heterogeneity in analyses and outcome measures hampered the reporting of overall effect sizes. Studies with adequate interrupted time series design reported a more mixed impact of safety warnings than before/after studies. Furthermore, this review shows the relevance of considering not only the intended but also the unintended effects of safety warnings.Conclusions: There is a clear need for further research with appropriate study designs and statistical analyses, with more attention to confounding factors such as media coverage, to understand the impact of safety-related regulatory action. [ABSTRACT FROM AUTHOR]

Background: Data mining of spontaneously reported adverse drug reactions (ADRs), using measures of disproportionality, is a valuable first evaluation step for drug safety signal detection. Of all ADRs reported for children and adolescents within VigiBase, vaccine-ADR pairs comprise more than half of the reports. ADRs concerning vaccines differ with respect to type and seriousness from other drugs, and therefore may influence signal detection for non-vaccine drugs if not accounted for appropriately. The potential influence of vaccines on safety signal detection for drugs was recently raised by the CIOMS Working Group VIII, who proposed that it may be appropriate to undertake automatic signal detection using both medicines and vaccines, and some analysis using vaccines only. However, it has not described for which types of ADRs or drugs subgroup analysis is beneficial.Objective: The aim of the study was to study the methodological aspects concerning the influence of a high prevalence of vaccine-related ADRs on signal detection within paediatric ADR data.Methods: We analysed all paediatric Individual Case Safety Reports (ICSRs) received by VigiBase between 2000 and 2006, and calculated the reporting odds ratio (ROR) for all unique drug-ADR pairs with at least three reports. The ROR was additionally calculated in subgroups of vaccine-ADR pairs and non-vaccine-ADR pairs and further in different age groups. A proportional change in the ROR for the different subgroups was calculated and the change in the number of signals of disproportional reporting (SDRs) after subgroup analysis was assessed.Results: Of all paediatric ICSRs (N = 218 840, of which 117 877 were vaccine-related), a total of 26 203 unique drug-ADR pairs were eligible for inclusion (5586 vaccine-related). A total of 1637 vaccine-related SDRs and 13 375 non-vaccine-related SDRs were detected in the crude analysis. Subgroup analysis by restricting to either vaccines or non-vaccines revealed 494 additional SDRs for vaccines (+30.2%) and 821 additional SDRs for non-vaccines (+6.1%). Subgroup analyses were only beneficial for non-vaccines if the ADR of interest was reported uncommonly for non-vaccines and beneficial for vaccines if the ADR was reported uncommonly for vaccines. Subgroup analysis for ADRs that were reported commonly for either vaccines or non-vaccines led to the disappearance of 272 SDRs for vaccines and 2721 SDRs for non-vaccines. We could empirically derive a model that predicts the change in ROR in the subgroups based on the proportion of vaccines within the total dataset.Conclusion: The high proportion of vaccine-related reports within paediatric ADR data has a large and mathematically predictable impact on signal detection in paediatric ADR data. Subgroup analysis reveals new SDRs that potentially represent genuine safety signals. The most inclusive and sensitive signal detection method would be the combination of a crude and subgroup-based data mining approach, based on the ratio between the proportion of vaccines within the ADR of interest and within all other ADRs. [ABSTRACT FROM AUTHOR]

Background: : Since the new legislation on risk management, which came into force in November 2005, an EU Risk Management Plan (EU-RMP) is a required part of the authorization dossier of innovative drugs licensed in the EU. The EU-RMP can include additional risk minimization activities (RMAs) to strengthen the benefit-risk balance of a drug. This study describes the additional RMAs of centrally authorized medicinal products authorized between 1 January 1995 and 1 January 2010.Methods: : The European Public Assessment Reports of all centrally authorized products were analysed to identify characteristics of the product (active substance, authorization date, Anatomical Therapeutic Chemical classification), the additional RMAs and the corresponding safety concerns (classified at Medical Dictionary for Regulatory Activities (MedDRA) System Organ Class level).Results: : Additional RMAs were identified for 58 of the 391 active substances that were authorized as of 1 January 2010. The proportion of active substances with additional RMAs was 5% among those authorized before, and 29% among those approved after the new risk management legislation. Since the new legislation, blood products and antineoplastic and immunomodulating agents most often had additional RMAs. All active substances with additional RMAs required the provision of educational material, most frequently involving healthcare professionals (n = 57) and the patient (n = 31). Thirty-three active substances required additional RMAs on top of the provision of educational material, most frequently including patient monitoring and screening (n = 19).Conclusions: : The proactive pharmacovigilance approach is evolving and the number of products with additional RMAs is growing since the introduction of the EU-RMP. The provision of educational material is the primary additional risk minimization strategy in the EU. The effect of additional RMA implementation has to be explored. [ABSTRACT FROM AUTHOR]

Objective: Numerous studies have suggested a decreased risk of cancer in patients with diabetes on metformin. Because different comparison groups were used, the effect magnitude is difficult to estimate. Therefore, the objective of this study was to further analyze whether, and to what extent, use of metformin is associated with a decreased risk of cancer in a cohort of incident users of metformin compared with users of sulfonylurea derivatives.Research Design and Methods: Data for this study were obtained from dispensing records from community pharmacies individually linked to hospital discharge records from 2.5 million individuals in the Netherlands. The association between the risk of cancer in those using metformin compared with those using sulfonylurea derivatives was analyzed using Cox proportional hazard models with cumulative duration of drug use as a time-varying determinant.Results: Use of metformin was associated with a lower risk of cancer in general (hazard ratio 0.90 [95% CI 0.88-0.91]) compared with use of sulfonylurea derivatives. When specific cancers were used as end points, similar estimates were found. Dosage-response relations were identified for users of metformin but not for users of sulfonylurea derivatives.Conclusions: In our study, cumulative exposure to metformin was associated with a lower risk of specific cancers and cancer in general, compared with cumulative exposure to sulfonylurea derivatives. However, whether this should indeed be seen as a decreased risk of cancer for the use of metformin or as an increased risk of cancer for the use sulfonylurea derivatives remains to be elucidated. [ABSTRACT FROM AUTHOR]

Background: Knowledge on the safety of new medicines is limited at the time of market entry. Nearly half of all drugs used to treat HIV registered in the EU required ≥1 Direct Healthcare Professional Communication (DHPC) in the past 10 years for safety issues identified post-approval.Objective: The aim was to evaluate the extent to which regulators and industry have addressed the risk of safety issues for HIV drugs based on prior experience with other drugs in the same class and whether doing so impacts development time of these drugs.Methods: HIV drugs receiving ≥1 DHPC in the Netherlands between January 1999 and December 2008 were identified. Each drug with a DHPC ('index' drug) was paired with subsequently approved HIV drug(s) in the same class (Anatomical Therapeutic Chemical [ATC] 4th level) ['follow-on' drugs]. Characteristics of safety issues were extracted from the DHPCs of the 'index' drugs. European Public Assessment Reports (EPARs) were reviewed regarding whether the safety issues had been considered during development and approval. Consideration of previously identified safety issues in 'follow-on' drug applications was assessed regarding attention paid to adverse drug reaction (ADR) symptoms in pre-marketing studies, Summary of Product Characteristics (SmPC) and postmarketing commitments, and whether size of the safety population was in accordance with Regulatory guidelines. 'Index' drugs were also paired with drugs in the same class already on the market ('older' drugs). For 'older' drugs, we identified whether the safety issue led to appropriate changes in the current SmPC (January 2011) compared with the SmPC at the time of marketing authorization. Clinical development time was assessed using time from first patent application to market authorization as proxy, and comparison was made between 'index' and 'follow-on' drugs.Results: For 9 (43%) of the 21 centrally authorized HIV drugs, 11 serious safety issues that required a DHPC were identified. Two drugs were excluded from our analysis (DHPCs related to contamination/medication error). Six 'index' drugs were paired, each with one to six 'follow-on' drugs. Three concerned drug-drug interactions (DDIs); the other three were intracranial haemorrhage, neuromuscular weakness and severe skin/hepatic reactions. All but one 'follow-on' drug had information in the EPAR on that specific ADR (i.e. attention was paid to the ADR). The DDIs were addressed in pre-marketing studies and/or the SmPC. Two of the other ADRs were addressed by postmarketing surveillance commitments; intracranial haemorrhage was not addressed. Three safety issues for two 'index' drugs could not be paired with a 'follow-on' drug as no drug in the same class was approved after the corresponding DHPCs were issued. Five of the nine safety issues were added to at least one of the current SmPCs for the 'older' drugs already on the market at the time of DHPC issue. Two safety issues were already in the SmPC of the 'older' drugs at time of market approval and two were not introduced into the SmPC of 'older' drugs. Population size to assess short-term safety complied with the guidelines for four 'index', seven 'follow-on' and three 'older' drugs; population size to assess long-term safety complied for one, three and two drugs, respectively. For five drugs, EPARs did not provide adequate information on population size. No statistically significant difference in development time between 'index' and 'follow-on' drugs was found.Conclusion: Generally, safety issues were taken into account in the approval process of other drugs in the class. The approaches were different and determined by the nature of the ADR. Taking safety issues into account in the approval process did not seem to impact on the time taken to perform the pre-approval clinical programme. [ABSTRACT FROM AUTHOR]

Background: Biologicals have specific characteristics, as compared with the small molecule drugs, and carry specific risks. Safety problems, for example infliximab and the risk for tuberculosis, have been identified via spontaneous reports of suspected adverse drug reactions (ADRs). However, in general there is limited data on the nature of spontaneously reported suspected ADRs for biologicals.Objective: To map the safety profile of biologicals as compared with all other drugs. In addition, mechanistic classes of biologicals will be compared.Methods: Data was obtained from the ADR database (VigiBase) maintained by the WHO Collaborating Centre for International Drug Monitoring. A disproportionality analysis was performed in which case reports for biologicals and all other drugs (the reference group), reported between January 1995 and December 2008, were selected. Vaccines were not included in the analysis. Suspected ADRs were classified according to Medical Dictionary for Regulatory Activities (MedDRA) version 12.0 at the System Organ Class (SOC) level. Biologicals were classified into mechanistic classes: antibodies, cytokines, enzymes, growth factors, hormones (reference group), interferons, receptors and others/various. The safety profile of the biologicals versus all other drugs in the database and of the various mechanistic classes of biologicals was compared using the proportional reporting ratio (PRR).Results: 191,004 case reports containing 546,474 suspected ADRs were reported for 62 different biologicals, and 2,556,209 case reports containing 8,761,522 suspected ADRs were reported for all other drugs (the reference group). It was found that two-thirds of all suspected ADRs reported for biologicals were reported for five active substances: etanercept (20.3%), interferon-beta-1a (15.6%), infliximab (11.6%), teriparatide (10.7%) and adalimumab (9.0%). Comparison of the safety profile of biologicals and the reference group showed that suspected ADRs for biologicals were more frequently reported in the SOCs 'Infections and infestations' (PRR 4.5), 'Surgical and medical procedures' (PRR 2.4) and 'Neoplasms benign, malignant and unspecified' (PRR 2.1), and less frequently reported in the SOCs 'Psychiatric disorders' (PRR 0.4), 'Vascular disorders' (PRR 0.4) and 'Pregnancy, puerperium and perinatal conditions' (PRR 0.4). Regarding the differences in safety profile between various mechanistic classes of biologicals, compared with hormones (reference group), 'Infections and infestations' were more frequently reported for receptors and antibodies. 'Neoplasms benign, malignant and unspecified' were more frequently reported for antibodies, cytokines, interferons and receptors, and less frequently for enzymes as compared with the reference group.Conclusions: In VigiBase, five biologicals comprise two-thirds of the suspected ADRs reported for biologicals, which might distort the relation found between a specific biological and a specific adverse event in case of quantitative signal detection. Therefore the choice of reference group to be used in case of quantitative signal detection should be considered very carefully. This study confirmed that biologicals have a different safety profile compared with all other drugs in the database and, within the group of biologicals, differences exist between mechanistic classes. Infections are, for example, frequently reported for receptors and antibodies, which often have an immune compromising effect. Such predictable safety issues should be specifically studied by preregistration clinical trials and/or targeted pharmacovigilance. In addition, since not all adverse reactions can be predicted or detected during development, spontaneous reporting remains an important tool for the early detection of signals. [ABSTRACT FROM AUTHOR]

Background: As pre-approval trials are inherently limited in assessing the complete benefit-risk profile of a new drug, serious safety issues may emerge once a drug gains widespread use after approval. Regulators face the dilemma of balancing timely market access with the need for complete data on risks. This challenge has led to a life-cycle approach but, so far, few data are available on post-approval safety issues requiring regulatory action.Objective: The aim of this study is to determine the frequency, timing and nature of safety issues that necessitated safety-related regulatory action in the form of a Direct Healthcare Professional Communication (DHPC) issued by pharmaceutical companies in collaboration with the Dutch Medicines Evaluation Board during the past decade.Methods: All DHPCs issued in the Netherlands from 1 January 1999 to 1 January 2009 were retrospectively collected from the national regulatory authorities. Elapsed time between the approval date and the issue of the DHPC was determined. Characteristics of the action including the nature of the safety issue (according to Medical Dictionary for Regulatory Activities [MedDRA] terminology), type of drug and procedural aspects of the regulatory action taken were reviewed. DHPC characteristics were tabulated and explorative non-parametric tests were performed to study the effect of safety issue, drug class, drug type, orphan drug and first-in-class status on elapsed time from approval to the DHPC.Results: 157 DHPCs were issued concerning 112 different active substances, approximately 9% (112/1200) of active substances available in the Netherlands in 2007. The number of DHPCs issued increased by 2.1 (95% CI 1.2, 3.1; p < 0.001) DHPCs per year over the past decade, reaching a total of 25 in 2008. The median time between approval and DHPC was 5.3 years (range 0.13-48 years). No significant trend in elapsed time to DHPC was observed in relation to the studied years (p = 0.06). One-third of all DHPCs were issued in the first 3 years after approval, but 27% (n = 43/157) of the DHPCs were issued 10 or more years after approval. Timing of DHPCs differed depending on safety issue, drug class, drug type and orphan drug status. DHPCs mostly concerned adverse events in the system organ class of 'cardiac disorders' (15%), 'injury, poisoning and procedural complications' (13%) and 'general disorders and administration site conditions' (10%). In ten cases the drug was eventually withdrawn. Withdrawal occurred a median duration of 2.4 years after registration (range of 1.5-48 years) and was most frequently due to cardiac disorders (including QT interval prolongation; four occasions) and hepatobiliary disorders (two occasions).Conclusions: In the past decade, the number of DHPCs has increased over time. This is likely caused by a multitude of factors: increased risk awareness by the public, media, regulators and other stakeholders; the type of drugs approved, such as orphan drugs and biologicals; and the regulatory process, including conditional approvals. The number of DHPCs may in the future increase further with the possibility of screening large epidemiological databases proactively for adverse drug events. Nine percent of all marketed drugs required a safety-related action. Regulatory action is taken shortly (<3 years) after market approval nearly as often as after intermediate (3-10 years) and long-term (>10 years) market exposure. These findings underline the need for risk management during the whole life cycle of a drug. [ABSTRACT FROM AUTHOR]

Background: Isotretinoin is very effective in the treatment of severe acne. However, because of the teratogenic properties of this agent an isotretinoin Pregnancy Prevention Programme (PPP) was implemented in the Netherlands to guarantee that treatment is contraindicated in women of reproductive age unless at least one effective method of contraception is used. Furthermore, the PPP stipulates that isotretinoin treatment should be managed by physicians or specialists experienced in treatment with this drug and that only monthly prescriptions are issued.Objective: To assess compliance with the Dutch isotretinoin PPP in women of reproductive age during the study period of 1 January 2005 to 31 December 2008.Methods: Detailed information on dispensed medication and co-medication was available from the Dutch Foundation of Pharmaceutical Statistics. Four types of outcome were studied: concomitant dispensing of hormonal contraceptive with isotretinoin; the proportion of specialist prescribing of isotretinoin; prescribing of conventional acne therapy prior to isotretinoin initiation; and isotretinoin dispensing exceeding the maximum amount. The use of contraceptives in women aged between 15 and 45 years was defined as concomitant if the period of systemic contraceptive use overlapped the period of isotretinoin dispensing for at least 10 days, or if any dispensing of an intrauterine or intravaginal contraceptive was recorded since the year 2000. Dispensings were separated into those prescribed by either specialists or general practitioners (GPs). The use of antibacterials, antiandrogens or topical agents against acne was checked 4 months prior to an isotretinoin dispensing, and a possible excess of the maximum amount of isotretinoin was defined as prescriptions of more than 100 defined daily doses.Results: During the study period, data were available for 442 Dutch pharmacies encompassing 4881 women of reproductive age using isotretinoin at least once during study period. Among women of reproductive age, the use of isotretinoin increased during the study period. The proportion of isotretinoin initiation with concomitant oral hormonal or intrauterine contraceptives was low (59.3% [95% CI 57.6, 61.0]). Initiation of isotretinoin by a specialist increased the chance for concomitant contraception by 26% (95% CI 6.0, 49.0); in 78.2% (95% CI 76.8, 79.6) of women, isotretinoin was initiated by a specialist. Conventional acne therapy up to 16 months prior to isotretinoin initiation was found in 70% of the women (70.3% [95% CI 66.0, 74.6]). In 1.4% (95% CI 1.0, 1.8) of cases of treatment initiation, the amount of isotretinoin dispensed on one prescription seemed too high.Conclusion: Attention should be paid to improving the implementation of the isotretinoin PPP. Despite clear guidelines and warnings in the product information, our study strongly suggests that concomitant use of isotretinoin and contraceptives is too low. Even though we will have missed non-pharmacological forms of contraception, these results raise doubts about the safe use of isotretinoin in women of reproductive age in the Netherlands. Furthermore, isotretinoin does not seem to be used in cases of severe acne only. Reserving isotretinoin prescribing to specialists may improve adherence to the PPP. [ABSTRACT FROM AUTHOR]

Background: Since November 2005, an EU Risk Management Plan (EU-RMP) has had to be submitted as part of a marketing application for all new chemical entities in the EU. In the EU-RMP, the safety profile of the medicine has to be described and pharmacovigilance activities should be proposed to study further safety concerns during use of the drug in the real-world setting. These activities include, for example, collection of spontaneously reported adverse events and post-authorization safety studies (PASS). Since the submission of an EU-RMP is a relatively new requirement, there is limited knowledge on the quality and completeness of the study protocols of PASS at the time of approval and there are no data on the influence of certain drug characteristics on the proposed pharmacovigilance activities.Objective: To examine the types of proposed pharmacovigilance activities in a sample of EU-RMPs, describe and evaluate the methodology of PASS, identify problems and propose remedies, and compare characteristics between biologicals and small molecules.Methods: Eighteen EU-RMPs (nine for biologicals, nine for small molecules) given a positive decision regarding the marketing application by the Committee for Medicinal Products for Human Use between November 2005 and May 2007 were included in this descriptive cohort study. The EU-RMPs were selected over time and different therapeutic areas. Classification of the safety concerns ('important identified risks', 'important potential risks', 'important missing information' within the EU-RMP was studied. For PASS, data source (registry, population-based database, sponsor-owned clinical trial database), source of study population to be included in PASS and comprehensiveness of study protocol (full protocol, limited protocol, study synopsis, short description, commitment without further information) were studied.Results: Compared to small molecules, safety concerns for biologicals were less frequently classified as important identified risks (relative risk [RR] 0.6; 95% CI 0.3, 1.0) and more frequently as important missing information (RR 1.6; 95% CI 1.0, 2.7). Forty-seven PASS were proposed; 31 for biologicals and 16 for small molecules. Compared with studies proposed in population-based databases (4 for biologicals, 8 for small molecules), studies in registries (18 for biologicals, 4 for small molecules) were more frequently proposed for biologicals than for small molecules (RR 2.5; 95% CI 1.1, 5.7). About 60% of the proposed PASS will include EU inhabitants. No full study protocols were submitted; 26% involved a limited study protocol, 33% a study synopsis, 37% a short description and 4% a commitment without further information.Conclusion: Approximately 40% of the study proposals for PASS were classified as a short description or a commitment to perform a study without further information, precluding an adequate scientific assessment. Studying non-EU populations may give rise to difficulties with generalizability of the results to the EU due to differences in patient characteristics, differences in the indication for the medicine and different healthcare systems. This study emphasizes the need for more complete study proposals to be submitted earlier on in the evaluation period and for the inclusion of EU inhabitants in PASS. In addition, differences in the characteristics between biologicals and small molecules, e.g. in the data source proposed, support the need for individualized tailored PASS depending on the type of drug. [ABSTRACT FROM AUTHOR]

Intussusception is a rare, potentially life-threatening condition in early childhood. It gained attention due to an unexpected association with the first rotavirus vaccine, RotaShield, which was subsequently withdrawn from the market. Across Europe, broad variations in intussusception incidence rates have been reported. This study provides a first estimate of intussusception incidence in young children in the Netherlands from 1 January 2008 to 31 December 2012, which could be used for future rotavirus safety monitoring. Our estimates are based on two different sources: electronic medical records from the primary healthcare database (IPCI), as well as administrative data from the Dutch hospital register (LBZ). The results from our study indicate a low rate of intussusception. Overall incidence rate in children < 36 months of age was 21.2 per 100,000 person-years (95% confidence interval (CI): 12.5-34.3) based on primary healthcare data and 22.6 per 100,000 person-years (95% CI: 20.9-24.4) based on hospital administrative data. The estimates suggest the upper and lower bound of the expected number of cases., (This article is copyright of The Authors, 2017.)

Purpose: In drug safety, there is a lack of guidance on how prioritization of safety issues should be performed. The aim of this literature review is to provide an overview of criteria used for signal prioritization and of the associated decision support frameworks., Methods: A search strategy was constructed to identify relevant articles in Medline/Embase databases from the period from 1 January 1995 to 31 August 2015. The prioritization criteria were extracted and classified in relevant categories., Results: From an initial set of 63 articles, 11 were retained for full review. The articles mentioned 48 criteria used in the prioritization process, with a median of six criteria per study [range: 1-16]. More than half of the criteria (63%), referred to strength of evidence while 19% related to public health impact, 14% to general public and media attention and 4% to novelty of the drug event association. Fifteen criteria were tested for predictive value with 11 showing positive results, most of them from the strength of evidence category. Six decision-making frameworks are presented, which incorporate criteria from various categories. Five of these frameworks were tested against expert decisions or by other means, but only in one database each and for a limited set of products., Conclusions: There is a wide range of prioritization criteria described in the literature; however, few of them demonstrated predictive value. Many criteria with predictive value were related to strength of evidence category and to novelty. There were few attempts at integrating different criteria in decision support frameworks. Five of the frameworks were tested for validity and showed usefulness, while at least three are already in use for prioritization. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Background: To describe patterns of antibiotic outpatient use in 3 European countries, including 2 new pediatric-specific quality indicators (QIs)., Methods: A cohort study was conducted, 2001-2010, using electronic primary care records of 2,196,312 children up to 14 (Pedianet, Italy) or 18 years (The Health Improvement Network, United Kingdom; Integrated Primary Care Information database, The Netherlands) contributing 12,079,620 person-years. Prevalence rates of antibiotic prescribing per year were calculated and antibiotics accounting (drug utilization) for 90% of all antibiotic prescriptions were identified (drug utilization 90% method). The ratio between users of broad to narrow-spectrum penicillins, cephalosporins and macrolides (B/N ratio) and 2 pediatric-specific QIs: the proportion of amoxicillin users (amoxicillin index) and the ratio between users of amoxicillin to broad-spectrum penicillins, cephalosporins and macrolides (A/B ratio) were determined., Results: The overall annual prevalence of antibiotic prescriptions was 18.0% in the Netherlands, 36.2% in the United Kingdom and 52.0% in Italy. Use was maximal in the first years of life. The number of antibiotics accounting for the drug utilization 90% was comparable. The B/N ratio varied widely from 0.3 to 74.7. The amoxicillin index was highest in the Netherlands and the United Kingdom (50-60%), lowest in Italy (30%) and worsened over time in the United Kingdom and Italy. The A/B ratio in 2010 was 0.3 in Italy, 1.7 in the Netherlands and 5.4 in the United Kingdom., Conclusions: The patterns of antibiotic prescribing varied highly with age and country. The pediatric-specific QIs combined with the total prevalence rate of use provide a clear picture of the trends of community childhood antibiotic prescribing, allowing monitoring of the impact of policy interventions.

Background and Objective: The availability of accurate product-specific exposure information is essential in the pharmacovigilance of biologicals, because differences in the safety profile may emerge between products containing the same active substance. In spontaneous adverse drug reaction (ADR) reports, drug exposure may, however, be misclassified, that is, attributed to the incorrect product. The aim of this study was to explore the effect of exposure misclassification on the time to detection of product-specific risks in spontaneous reporting systems., Methods: We used data simulations to explore the effect of exposure misclassification. We simulated an active substance-specific subset of a spontaneous reporting system and used the proportional reporting ratio for signal detection. The effect of exposure misclassification was evaluated in three test cases representing product-specific ADRs that may occur for biologicals and studied in relative terms by varying the model parameters (market share and relative risk)., Results: We found that exposure misclassification results in the largest delay in identification of risks that have a weak association (relative risk < 2 or 3) with the product of interest and in situations where the product associated with the unique risk has a large (>50%) market share. The absolute public health impact of exposure misclassification, in terms of cases/time to detection, varied considerably across the test cases., Conclusion: Exposure misclassification in ADR reports may result in a delayed detection of product-specific risks, particularly in the detection of weak drug-event associations. Our findings can help inform the future implementation and refinement of product-specific and batch-specific signal detection procedures., (Copyright © 2015 John Wiley & Sons, Ltd.)

Background and Objective: Spontaneous reporting systems (SRSs) remain the cornerstone of post-marketing drug safety surveillance despite their well-known limitations. Judicious use of other available data sources is essential to enable better detection, strengthening and validation of signals. In this study, we investigated the potential of electronic healthcare records (EHRs) to be used alongside an SRS as an independent system, with the aim of improving signal detection., Methods: A signal detection strategy, focused on a limited set of adverse events deemed important in pharmacovigilance, was performed retrospectively in two data sources-(1) the Exploring and Understanding Adverse Drug Reactions (EU-ADR) database network and (2) the EudraVigilance database-using data between 2000 and 2010. Five events were considered for analysis: (1) acute myocardial infarction (AMI); (2) bullous eruption; (3) hip fracture; (4) acute pancreatitis; and (5) upper gastrointestinal bleeding (UGIB). Potential signals identified in each system were verified using the current published literature. The complementarity of the two systems to detect signals was expressed as the percentage of the unilaterally identified signals out of the total number of confirmed signals. As a proxy for the associated costs, the number of signals that needed to be reviewed to detect one true signal (number needed to detect [NND]) was calculated. The relationship between the background frequency of the events and the capability of each system to detect signals was also investigated., Results: The contribution of each system to signal detection appeared to be correlated with the background incidence of the events, being directly proportional to the incidence in EU-ADR and inversely proportional in EudraVigilance. EudraVigilance was particularly valuable in identifying bullous eruption and acute pancreatitis (71 and 42 % of signals were correctly identified from the total pool of known associations, respectively), while EU-ADR was most useful in identifying hip fractures (60 %). Both systems contributed reasonably well to identification of signals related to UGIB (45 % in EudraVigilance, 40 % in EU-ADR) but only fairly for signals related to AMI (25 % in EU-ADR, 20 % in EudraVigilance). The costs associated with detection of signals were variable across events; however, it was often more costly to detect safety signals in EU-ADR than in EudraVigilance (median NNDs: 7 versus 5)., Conclusion: An EHR-based system may have additional value for signal detection, alongside already established systems, especially in the presence of adverse events with a high background incidence. While the SRS appeared to be more cost effective overall, for some events the costs associated with signal detection in the EHR might be justifiable.

Progressive multifocal leukoencephalopathy (PML) has been identified as a serious adverse drug reaction (ADR) of several immunomodulatory biologicals. In this study, we contrasted the reporting patterns of PML for two biologicals for which the risk was identified at different points in their lifecycle: natalizumab (before reapproval) and rituximab (nine years postapproval). We found that, apart from the differences in clinical characteristics (age, gender, indication, time to event, fatality), which reflect the diversity in context of use, PML reports for natalizumab were more complete and were received sooner after occurrence. This study serves as an important reminder that spontaneous reports should only be used with great caution to quantify and compare safety profiles across products over time. The observed variability in reporting patterns and heterogeneity of PML cases presents challenges to such comparisons. Lumping uncharacterized PML reports together without taking these differences into account may result in biased comparisons and flawed conclusions about differential safety., (© 2015 American Society for Clinical Pharmacology and Therapeutics.)

Aim: Electronic healthcare record (EHR)-based surveillance systems are increasingly being developed to support early detection of safety signals. It is unknown what the power of such a system is for surveillance among children and adolescents. In this paper we provide estimates of the number and classes of drugs, and incidence rates (IRs) of events, that can be monitored in children and adolescents (0-18 years)., Methods: Data were obtained from seven population-based EHR databases in Denmark, Italy, and the Netherlands during the period 1996-2010. We estimated the number of drugs for which specific adverse events can be monitored as a function of actual drug use, minimally detectable relative risk (RR) and IRs for 10 events., Results: The population comprised 4 838 146 individuals (25 575 132 person years (PYs)), who were prescribed 2170 drugs (1 610 631 PYs drug-exposure). Half of the total drug-exposure in PYs was covered by only 18 drugs (0.8%). For a relatively frequent event like upper gastrointestinal bleeding there were 39 drugs for which an association with a RR ≥4, if present, could be investigated. The corresponding number of drugs was eight for a rare event like anaphylactic shock., Conclusion: Drug use in children is rare and shows little variation. The number of drugs with enough exposure to detect rare adverse events in children and adolescents within an EHR-based surveillance system such as EU-ADR is limited. Use of additional sources of paediatric drug exposure information and global collaboration are imperative in order to optimize EHR data for paediatric safety surveillance., (© 2015 The British Pharmacological Society.)

Objective: To study the dispensing of potentially teratogenic drugs in the 12-month period before as well as during pregnancy in the Netherlands., Design: Population-based study., Setting: A cohort was constructed using a linkage between the PHARMO Database Network and the Netherlands Perinatal Registry (PRN)., Population: A total of 203 962 Dutch pregnancies reported between 1999 and 2007 METHODS: Drug-dispensing information was identified from the PHARMO Database Network for the 12-month period before conception and during pregnancy. Drugs with either a Swedish FASS 'D' classification, an Australian ADEC or American FDA 'D' or 'X' classification were considered potentially teratogenic (n = 202)., Mean Outcome Measures: Proportion of pregnancies that received potentially teratogenic drugs in the 12-month period before and during pregnancy and specific for the risk category X drugs and newly initiated drugs., Results: Sixteen percent of the pregnancies received a potentially teratogenic drug in the 12-month period before and 5.07% during pregnancy. Doxycycline and paroxetine were most frequently received during pregnancy by 1.01% and 0.85% of women, respectively; 0.66% of the women received a risk category X drug during pregnancy which most frequently consisted of triptorelin (0.25%), norethisterone (0.22%) and simvastatin (0.03%). Fifty-three percent of the women who received a potentially teratogenic drug during pregnancy received this for the first time during the study period. These percentages were heterogeneous between therapeutic drug classes., Conclusions: Five percent of the pregnancies received a potentially teratogenic drug during pregnancy and 0.66% received a drug from the risk category X. It may be possible to reduce these proportions when reasons for prescription have been explored., (© 2014 Royal College of Obstetricians and Gynaecologists.)

Individual case safety reports (ICSRs) are a cornerstone in drug safety surveillance. The knowledge on using these data specifically for children is limited. We studied characteristics of pediatric ICSRs reported to the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). Public available ICSRs reported in children (0-18 years) to FAERS were downloaded from the FDA-website for the period Jan 2004-Dec 2011. Characteristics of these ICSRs, including the reported drugs and events, were described and stratified by age-groups. We included 106,122 pediatric ICSRs (55% boys and 58% from United States) with a median of 1 drug [range 1-3] and 1 event [1-2] per ICSR. Mean age was 9.1 years. 90% was submitted through expedited (15-days) (65%) or periodic reporting (25%) and 10% by non-manufacturers. The proportion and type of pediatric ICSRs reported were relatively stable over time. Most commonly reported drug classes by decreasing frequency were 'nervous system drugs' (58%), 'antineoplastics' (32%) and 'anti-infectives' (25%). Most commonly reported system organ classes were 'general' (13%), 'nervous system' (12%) and 'psychiatric' (11%) disorders. Duration of use could be calculated for 19.7% of the reported drugs, of which 14.5% concerned drugs being used long-term (>6 months). Knowledge on the distribution of the drug classes and events within FAERS is a key first step in developing pediatric specific methods for drug safety surveillance. Because of several differences in terms of drugs and events among age-categories, drug safety signal detection analysis in children needs to be stratified by each age group.

Aims: To compare the values regulators attach to different drug effects of oral antidiabetic drugs with those of doctors and patients., Methods: We administered a 'discrete choice' survey to regulators, doctors and patients with type 2 diabetes in The Netherlands. Eighteen choice sets comparing two hypothetical oral antidiabetic drugs were constructed with varying drug effects on glycated haemoglobin, cardiovascular risk, bodyweight, duration of gastrointestinal complaints, frequency of hypoglycaemia and risk of bladder cancer. Responders were asked each time which drug they preferred., Results: Fifty-two regulators, 175 doctors and 226 patients returned the survey. Multinomial conditional logit analyses showed that cardiovascular risk reduction was valued by regulators positively (odds ratio 1.98, 95% confidence interval 1.11-3.53), whereas drug choices were negatively affected by persistent gastrointestinal problems (odds ratio 0.24, 95% confidence interval 0.14-0.41) and cardiovascular risk increase (odds ratio 0.49, 95% confidence interval 0.27-0.87). Doctors and patients valued these effects in a similar manner to regulators. The values that doctors attached to large changes in glycated haemoglobin and that both doctors and patients attached to hypoglycaemia and weight gain also reached statistical significance. No group's drug choice was affected by a small absolute change in risk of bladder cancer when presented in the context of other drug effects. When comparing the groups, the value attached by regulators to less frequent hypoglycaemic episodes was significantly smaller than by patients (P = 0.044)., Conclusions: Regulators may value major benefits and risks of drugs for an individual diabetes patient mostly in the same way as doctors and patients, but differences may exist regarding the value of minor or short-term drug effects., (© 2014 The British Pharmacological Society.)

Introduction: Traceability is important in the postmarketing surveillance of biologicals, since changes in the manufacturing process may give rise to product- or batch-specific risks. With the expected expansion of the biosimilar market, there have been concerns about the ability to trace individual products within pharmacovigilance databases., Areas Covered: The authors discuss the present challenges in the traceability of biologicals in relation to pharmacovigilance, by exploring the processes involved in ensuring traceability. They explore both the existing systems that are in place for the recording of exposure information in clinical practice, as well as the critical steps involved in the transfer of exposure data to various pharmacovigilance databases., Expert Opinion: The existing systems ensure the traceability of biologicals down to the manufacturer within pharmacy records, but do not support the routine recording of batch information. Expected changes in supply chain standards provide opportunities to systematically record detailed exposure information. Spontaneous reporting systems are the most vulnerable link in ensuring traceability, due to the manual nature of data transfer. Efforts to improve the traceability should, in the short term, be focused toward encouraging health professionals and patients to systematically record and report detailed exposure information. Long-term solutions lie in expanding the accessibility to, and increasing the electronic exchange of exposure data.

Background and Objective: New pharmacovigilance legislation in the European Union has underlined the importance of signal management, giving the European Medicines Agency's newly established Pharmacovigilance Risk Assessment Committee (PRAC) the mandate to oversee all aspects of the use of medicinal products including detection, assessment, minimization, and communication relating to the risk of adverse reactions. In this study, we describe the signals as brought to the PRAC during the first 18 months of its operation and the ensuing regulatory actions., Methods: Data were collected from publicly available sources, for the period July 2012-December 2013, classified according to predefined rules, and described using the appropriate descriptive statistics. Suspected adverse drug reactions were categorized into the Medical Dictionary for Regulatory Affairs and drug names were mapped to the Anatomical Therapeutic Chemical codes., Results: During the study period, 125 signals concerning 96 medicinal products were discussed by the PRAC. The majority of signals were triggered by spontaneous reports (62%) and the median drug age (since marketing authorization) for drugs that prompted a signal was 12 years, significantly less compared with drugs that had no signal within the same period (20 years). The mean time until a decision was reached by the PRAC was 75 days (median 30 days, range 0-273) with 43% of all decisions taken during the first meeting. The decisions to start a referral and to send a direct healthcare professional communication took the least amount of time [54 days (median 27 days, range 0-186) and 51 days (median 0 days, range 0-153)]., Conclusions: The importance of spontaneous reporting in signal detection and monitoring of safety issues throughout the entire life cycle of a medicinal product is confirmed in this study. The amount of time a drug has been on the market is correlated with the number of signals detected. The PRAC decision-making process seems efficient particularly with respect to serious concerns; its role in improving signal prioritization and real-time signal management will be further clarified in its subsequent years of operation.

Risk Management Plans (RMPs) have become a cornerstone in the pharmacovigilance of new drugs in Europe. The RMP was introduced in 2005 to support a proactive approach in gaining knowledge on safety concerns through early planning of pharmacovigilance activities. However, the rate at which uncertainties in the safety profile are resolved through this proactive approach is unknown. We therefore examined the evolution of safety concerns in the RMP after initial approval for a selected cohort of 48 drugs, to provide insight into the knowledge gain over time. We found that 20.7% of the uncertainties existing at approval had been resolved 5 years after approval. Because new uncertainties were included in the RMP at a similar rate, the overall number of uncertainties remained approximately equal. The relatively modest accrual of knowledge, as demonstrated in this study through resolution of uncertainties, suggests that opportunities for optimization exist while ensuring feasible and risk-proportionate pharmacovigilance planning.

Objective: To estimate isotretinoin exposure in Dutch pregnant women despite the implemented pregnancy prevention programme (PPP) and second, to analyse the occurrence of adverse fetal or neonatal outcomes in these isotretinoin exposed pregnancies., Design: Population-based study., Setting: The Netherlands., Participants: A cohort of 203,962 pregnancies with onset between 1 January 1999 and 1 September 2007 consisting of 208,161 fetuses or neonates., Main Outcome Measures: Isotretinoin exposure in the 30 days before or during pregnancy. Proportions of adverse fetal or neonatal outcomes, defined as intrauterine deaths ≥16 week of gestation and neonates with major congenital anomalies. ORs with 95% CIs adjusted for maternal age were calculated to estimate the risk of adverse fetal or neonatal outcome after maternal isotretinoin exposure., Results: 51 pregnancies, 2.5 (95% CI 1.9 to 3.3) per 10,000 pregnancies, were exposed to isotretinoin despite the pregnancy prevention programme. Forty-five of these pregnancies, 2.2 (95% CI 1.6 to 2.9) per 10,000 pregnancies, were exposed to isotretinoin during pregnancy and six additional women became pregnant within 30 days after isotretinoin discontinuation. In 60% of isotretinoin exposed pregnancies, women started isotretinoin while already pregnant. In five out of the 51 isotretinoin exposed pregnancies (53 fetuses), 9.4% (95% CI 1.3% to 17.6%), had an adverse fetal or neonatal outcome. The OR for adverse fetal or neonatal outcomes after isotretinoin exposure in 30 days before or during pregnancy was 2.3 (95% CI 0.9 to 5.7) after adjustment for maternal age., Conclusions: Although a PPP was already implemented in 1988, we showed that isotretinoin exposed pregnancies and adverse fetal and neonatal events potentially related to the exposure still occur. These findings from the Netherlands add to the evidence that there is no full compliance to the isotretinoin PPP in many Western countries. Given the limited success of iPLEDGE, the question is which further measures are able to improve compliance., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: The 5α-reductase inhibitors (5-ARI) finasteride and dutasteride are indicated for the treatment of lower urinary tract symptoms caused by benign prostatic hyperplasia. Case reports have suggested that 5-ARIs increase the risk for male breast cancer, with no conclusive evidence. The objective of this study was to quantify the association between use of 5-ARIs and the risk for male breast cancer., Methods: A case-control study was conducted with data from the United Kingdom Clinical Practice Research Datalink database among all men aged 45 years and older in the period 1 January 1992 to 31 December 2011. Cases of men diagnosed with breast cancer were matched to up 10 controls on age and general practice. Crude and adjusted odds ratios were estimated for the risk of breast cancer associated with the use of 5-ARIs., Results: Three hundred and ninety-eight cases were identified and matched to 3,930 controls. Ever use of 5-ARIs was associated with an adjusted odds ratio for breast cancer of 1.08 (95 % CI 0.62-1.87) compared to non-users. Increasing cumulative duration of treatment showed no increasing risks: adjusted odds ratios for use for less than 280, for 280 to 1,036 and for more than 1,036 days were 1.21 (95 % CI 0.47-3.10), 0.94 (95 % CI 0.36-2.41) and 1.29 (95 % CI 0.54-3.08), respectively., Conclusions: In this study, there was no evidence of an association between short- or long-term treatment with 5-ARIs and the risk for breast cancer in older men.

Background: Chlorthalidone and hydrochlorothiazide are often considered as interchangeable. However, greater (nighttime) blood pressure reduction, and alleged pleiotropic effects have renewed the interest in chlorthalidone. A recent study showed an increased risk of adverse events with chlorthalidone, including hyponatremia., Methods: To investigate differences in risk of hyponatremia between chlorthalidone and hydrochlorothiazide, adjusted for daily dose, we conducted a population-based case-control study within the Dutch IPCI (Integrated Primary Care Information) database. The study population included all subjects ≥18 years without diabetes mellitus, heart failure, liver failure, and malignancy, who were registered in the IPCI database from 1996 to 2011. Cases were subjects with a serum sodium <130 millimoles per liter or hospitalization due to hyponatremia. Controls were matched on practice, age within 5 years, sex, and date of onset., Results: A total of 1033 cases of hyponatremia were identified. Hyponatremia was more common with chlorthalidone than with hydrochlorothiazide at equal dose per day: adjusted odds ratio was 2.09 (95% confidence interval [CI], 1.13-3.88) for 12.5 milligrams per day and 1.72 (95% CI, 1.15-2.57) for 25 milligrams per day. Risks were not significantly increased with chlorthalidone compared with twice the dose per day of hydrochlorothiazide., Conclusions: This is the first study that shows an increased risk of hyponatremia with chlorthalidone relative to hydrochlorothiazide at equal milligram-to-milligram dose per day. The need for a lower dose of chlorthalidone than hydrochlorothiazide to achieve similar blood pressure reduction likely compensates for the increased risk of hyponatremia at equal dose., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Acute kidney injury (AKI) might complicate antihypertensive therapy. In The Netherlands, general practitioner clinical practice guidelines provide clear recommendations on monitoring of renal function to minimize this risk. Our objective was to investigate how day-to-day clinical practice corresponds to the guidelines., Methods: We conducted a retrospective cohort study in a dynamic population, using data on >9,000 adults that was retrieved from the Integrated Primary Care Information database. We investigated whether serum creatinine (SCR) was measured within 30 and 365 days after the start of (combined) use of a diuretic, an angiotensin-converting enzyme inhibitor, and/or angiotensin receptor blocker. We also investigated the association between calendar year, sex, type of therapy, risk factors for AKI and practice and SCR measurement., Results: Of 6,593 subjects who met the study criteria for single drug therapy, SCR was measured in 1,233 subjects within 30 days and in 3,896 subjects within 365 days. For combined drug therapy recipients (n = 2,497), these were 545 and 1,687, respectively. Associated cumulative probabilities were 19 % and 66 % with single drug therapy, and 22 % and 74 % with combined drug therapy. Significant differences were observed between practices. SCR measurement was associated with other characteristics, except for sex. Within 365 days, SCR increased >30 % of baseline in 103 subjects (1.6 %) after the start of single drug therapy, and in 85 (3.4 %) subjects who initiated combined drug therapy. In the majority (>70 %) of these subjects, this did not result in subsequent monitoring or adjustment of antihypertensive treatment., Conclusions: Results from this study suggest that, on average, renal function is not monitored as strictly as recommended by relevant clinical practice guidelines.

Purpose: Because most population-based studies on the epidemiology of chronic kidney disease (CKD) are cross-sectional, there is, except for end-stage renal disease, hardly any information on incidence rates., Methods: We conducted a retrospective cohort study in a dynamic population, using data of 784,563 adult participants retrieved from the Integrated Primary Care Information database, a primary care database containing the complete electronic longitudinal medical records. CKD (both incidence and prevalence) was based on (1) an increased urine albumin-to-creatinine ratio, (2) a decreased estimated glomerular filtration rate, or (3) explicit statement in the medical record. Results were stratified by age according to the WHO standard population, sex, and diabetes mellitus., Results: Based on a single measurement only, the incidence rate of CKD in adults was 1,213 per 100,000 person-years, and 6.7 percent of the adult population had a prevalent diagnosis of CKD. The incidence rate increased by age and was the highest in participants with diabetes with an incidence of 25,000 per 100,000 person-years, affecting over 75 percent of participants with diabetes., Conclusions: This is the first study to report the incidence rates of all stages of CKD for the entire adult population, stratified by sex, 5-year age groups, and diabetes. Our data demonstrate that the incidence of CKD increases with age and is the highest in participants with diabetes mellitus.

Background: At time of approval, knowledge of the full benefit risk of any drug is limited, in particular with regards to safety. Post-approval surveillance of potential drug safety concerns is recognized as an important task of regulatory agencies. For innovative, often first-in-class drugs, safety knowledge at time of approval is often even less extensive and these may require tighter scrutiny post approval., Objective: We evaluated whether more post-approval serious safety issues were identified for drugs with a higher level of innovation., Methods: A cohort study was performed that included all new active substances approved under the European Centralized Procedure and for which serious safety issues were identified post-approval from 1 January 1999 to 1 January 2012. Serious safety issues were defined as issues requiring a Direct Healthcare Professional Communication to alert individual healthcare professionals of a new serious safety issue, or a safety-related drug withdrawal. Data were retrieved from publicly available websites of the Dutch Medicines Evaluation Board and the European Medicines Agency. The level of innovation was scored using a validated algorithm, grading drugs as important (A), moderate (B) or modest (C) innovations or as pharmacological or technological (pharm/tech) innovations. The data were analyzed using appropriate descriptive statistics and Kaplan-Meier analysis, with a Mantel-Cox log-rank test, and Cox-regression models correcting for follow-up duration, to identify a possible trend in serious safety issues with an increasing level of innovation., Results: In Europe, 279 new drugs were approved between 1999 and 2011. Fifty-nine (21 %) were graded as important, 63 (23 %) moderate, or 34 (12 %) modest innovations and 123 (44 %) as non-innovative (pharm/tech), while 15 (25 %), 13 (21 %), 8 (24 %) and 17 (14 %) had post-approval safety issues, respectively (p = 0.06, linear-by-linear test). Five drugs were withdrawn from the market. The Kaplan-Meier-derived probability for having a first serious safety issue was statistically significant, log-rank (Mantel-Cox) p = 0.036. In the final adjusted Cox proportional hazard model there was no statistically significant difference in occurrence of a first serious safety issue for important, moderate and modest innovations versus non-innovative drugs; hazard ratios 1.76 (95 % CI 0.82-3.77), 1.61 (95 % CI 0.76-3.41)], and 1.25 (95 % CI 0.51-3.06), respectively., Conclusion: A higher level of innovation was not clearly related to an increased risk of serious safety issues identified after approval.

Purpose: "Additional" risk minimisation measures (aRMMs) can be necessary to optimise the benefit-risk balance of a drug. Evaluation of effectiveness of these measures has become mandatory with the new European Union (EU) pharmacovigilance legislation in force since July 2012. The aim of this study was to classify the aRMMs in the EU with a special emphasis on the possibilities to analyse the effectiveness of these aRMMs in existing electronic healthcare databases (EHDs)., Methods: European Public Assessment Reports were reviewed to identify key elements of the aRMMs. Researchers categorised the key elements based on the objectives, i.e. knowledge change or behavioural change and sub-categorised the behavioural changes. They assessed for each key element if it would be eligible for analysis in existing EHDs., Results: 68 drugs with aRMMs contained 801 key elements of which 57% aimed at behavioural changes. 22% of all key elements, all aimed behavioural changes, were assessed eligible for analysis in existing EHDs. These mainly concerned recommendations targeted at healthcare professionals regarding drug prescription, e.g. dose recommendations, contraindications or the need to perform laboratory tests for patient monitoring., Conclusions: Only a limited proportion of key elements of the aRMMs could potentially be monitored in existing EHDs as these data sources cannot capture all the required data. Due to difference between existing EHDs, not necessarily all available EHDs are appropriate for every drug or aRMM. To facilitate rapid evaluation of aRMM implementation and timely adjustments, industry and regulatory authorities should agree well-defined key elements of aRMMs leading to unambiguous actions of the target group., (Copyright © 2013 John Wiley & Sons, Ltd.)

Background: The usefulness and the impact of Direct Healthcare Professional Communications (DHPCs, or 'Dear Doctor letters') in changing the clinical behaviour of physicians have been debated. Changes in the current risk communication methods should preferably be based on the preferences of the healthcare professionals, to optimize the uptake of the message., Objective: The aim of this study was to assess whether safety issues are communicated more effectively with an additional e-mail sent by the Dutch Medicines Evaluation Board (MEB) than with the DHPC only., Methods: A randomized controlled trial was conducted amongst ophthalmologists and hospital pharmacists in the Netherlands, who were the target group of a DHPC that was issued for pegaptanib, a drug that is administered intra-ocularly in patients with macular degeneration. The intervention group (N = 110) received the pegaptanib DHPC, as well as the MEB e-mail. The control group (N = 105) received the traditional paper-based DHPC only. Two weeks later, the study population received an invitation to fill out an online questionnaire. Questions were asked about the respondents' knowledge and attitude regarding the pegaptanib issue, and any action they had consequently taken. Additional questions were asked about their satisfaction with the DHPC and the e-mail, and their preferred source of such information., Results: Forty respondents (18.6%) completed the questionnaire. Eighty-one percent of the respondents in the intervention group (N = 21) and 47% of the control group (N = 19) correctly indicated that a serious increase in intra-ocular pressure could be caused by pegaptanib injections (Fishers' exact test, p = 0.046). Nine respondents in the intervention group versus none of the control group respondents indicated that they had taken action in response to the pegaptanib safety issue (Fishers' exact test, p = 0.01). The majority of both the intervention group and the control group confirmed that they would like to receive an MEB e-mail with safety information about drugs in the future (90 and 95 %, respectively)., Conclusion: The results of this study indicate that an additional e-mail might strengthen the uptake of the safety information provided to healthcare professionals, who prefer to receive an e-mail from the MEB as a source of such information, as well as the DHPC. This study may serve as a starting point for new strategies to improve risk communication regarding safety issues associated with drugs and its impact on prescribing.

Background: Adverse drug reactions (ADRs) of biopharmaceuticals can be batch or product specific, resulting from small differences in the manufacturing process. Detailed exposure information should be readily available in systems for postmarketing safety surveillance of biopharmaceuticals, including spontaneous reporting systems (SRSs), in which reports of ADRs are collected., Objective: The aim of this study was to explore the current status of traceability of biopharmaceuticals in the US and the EU up to patient level in SRSs., Design and Setting: A cross-sectional study was conducted over the period 2004-2010, including ADR reports from two major SRSs: the FDA Adverse Event Reporting System (FAERS) in the US and EudraVigilance (EV) in the EU., Main Outcome Measures: The availability of batch numbers was determined for biopharmaceuticals, and compared with small molecule drugs. For biopharmaceuticals for which a biosimilar has been approved for marketing in the EU, the identifiability of the product (i.e. the possibility of distinguishing the biosimilar from the reference biopharmaceutical) was determined., Results: A total of 2,028,600 unique ADR reports were identified in the FAERS, reporting a total of 591,380 biopharmaceuticals (of which 487,065 were suspected). In EV there were 2,108,742 unique ADR reports, reporting a total of 439,971 biopharmaceuticals (356,293 suspected). Overall, for 24.0 % of the suspected biopharmaceuticals in the FAERS and 7.4 % of the suspected small molecule drugs (p < 0.001) batch numbers were available. A similar pattern was seen in EV: for 21.1 % of the suspected biopharmaceuticals batch numbers were available, compared with only 3.6 % of the small molecule drugs (p < 0.001). In both SRSs, consumers were most likely to report a batch number for suspected biologicals (36.3 % in the FAERS and 40.7 % in EV). A total of 13,790 biopharmaceuticals (9,759 suspected) for which a biosimilar has been approved in the EU were identified in EV. For 90.4 % of these biopharmaceuticals and 96.2 % of the suspected biopharmaceuticals the product was clearly identifiable., Conclusion: This study underlines the need for improving traceability of biopharmaceuticals, in particular with respect to individual batches, allowing better identification and monitoring of postmarketing safety issues related to biopharmaceuticals.

Background: Recent studies suggest that overanticoagulation impairs renal function in patients on warfarin therapy, due to renal tubular obstruction from glomerular hemorrhage., Methods: Data from the Rotterdam Study (The Netherlands), a prospective population-based cohort study of patients 55 years and older, were used for this study. Information on vitamin K antagonist (VKA) therapy was obtained from the regional anticoagulation clinic, where prothrombin times were monitored every 1-6 weeks depending on target level and stability of the international normalized ratio (INR). Linear regression was performed to study the association between the cumulative number of instances of overanticoagulation (defined as a measurement of an INR >6.0) and the change in renal function between baseline and third examination round based on estimated glomerular filtration rate (CKD-EPI equation). Age, sex, baseline renal function, baseline and incident heart failure, and indication for VKA therapy were included as potential confounders., Results: Information was available for analysis on 2,802 study participants in whom overanticoagulation was significantly associated with a decline in renal function, after adjustment for confounding by age, sex, heart failure, baseline glomerular filtration rate and indication for VKA therapy (-0.180 ml/min per 1.73 m(2) per year per event for INR >6.0, p = 0.030)., Conclusions: Overanticoagulation (INR >6.0) is associated with a decline in renal function. Further studies are needed to evaluate the causal role of different degrees of overanticoagulation, including transient effects, in high-risk groups, and the association with the new oral anticoagulants.

Serious safety issues relating to drugs are communicated to health-care professionals via Direct Health-Care Professional Communications (DHPCs). We explored which characteristics determined the impact of DHPCs issued in the Netherlands for ambulatory-care drugs (2001-2008). With multiple linear regression, we examined the impact on the relative change in new drug use post-DHPC of the following: time to DHPC, trend in use, degree of innovation, specialist drug, first/repeated DHPC, DHPC template, and type of safety issue. DHPCs have less impact on use of specialist drugs than nonspecialist drugs (P < 0.05). The DHPCs' impact increased after availability of a template emphasizing the main problem (P < 0.05), and for safety issues with a risk of death and/or disability (both P < 0.05) (adjusted R² = 0.392). Risk communication can be effective, specifically in case of well-structured information, and very serious safety issues. Effectiveness may improve by tailoring DHPCs and adding other communication channels, for example for drugs that are increasingly being used.

Background: At the time of approval of a new medicine, there are few long-term data on the medicine's benefit-risk balance. Clinical trials are designed to demonstrate efficacy, but have major limitations with regard to safety in terms of patient exposure and length of follow-up. This study of the number of patients who had been administered medicines at the time of medicine approval by the European Medicines Agency aimed to determine the total number of patients studied, as well as the number of patients studied long term for chronic medication use, compared with the International Conference on Harmonisation's E1 guideline recommendations., Methods and Findings: All medicines containing new molecular entities approved between 2000 and 2010 were included in the study, including orphan medicines as a separate category. The total number of patients studied before approval was extracted (main outcome). In addition, the number of patients with long-term use (6 or 12 mo) was determined for chronic medication. 200 unique new medicines were identified: 161 standard and 39 orphan medicines. The median total number of patients studied before approval was 1,708 (interquartile range [IQR] 968-3,195) for standard medicines and 438 (IQR 132-915) for orphan medicines. On average, chronic medication was studied in a larger number of patients (median 2,338, IQR 1,462-4,135) than medication for intermediate (878, IQR 513-1,559) or short-term use (1,315, IQR 609-2,420). Safety and efficacy of chronic use was studied in fewer than 1,000 patients for at least 6 and 12 mo in 46.4% and 58.3% of new medicines, respectively. Among the 84 medicines intended for chronic use, 68 (82.1%) met the guideline recommendations for 6-mo use (at least 300 participants studied for 6 mo and at least 1,000 participants studied for any length of time), whereas 67 (79.8%) of the medicines met the criteria for 12-mo patient exposure (at least 100 participants studied for 12 mo)., Conclusions: For medicines intended for chronic use, the number of patients studied before marketing is insufficient to evaluate safety and long-term efficacy. Both safety and efficacy require continued study after approval. New epidemiologic tools and legislative actions necessitate a review of the requirements for the number of patients studied prior to approval, particularly for chronic use, and adequate use of post-marketing studies. Please see later in the article for the Editors' Summary.

Purpose: To assess the compliance with the isotretinoin Pregnancy Prevention Programme (PPP) by evaluating the use of prescribed contraceptives among isotretinoin users. The PPP contains a requirement for the use of contraceptive methods for women of childbearing potential., Methods: A drug utilisation study was performed using data from a drug prescription database (containing Dutch community pharmacy data) covering a population of 500 000 patients. Contraceptive use in female isotretinoin users and in a reference group of female non-isotretinoin users (aged 15-49 years) was compared using data from 1999 until 2006 in 2-year periods. Descriptive statistics were used., Results: Of the female isotretinoin users (n = 651), 52%-54% filled prescriptions on contraceptives in strict accordance to the PPP, used before, during, and after discontinuation of isotretinoin, compared with 39%-46% in the reference group. A more liberal approach of a minimum of one prescription for a contraceptive method showed 61%-64% use of contraceptives among isotretinoin users. Similar patterns were seen when data were broken down in age groups. Furthermore, a higher proportion of female patients using isotretinoin prescribed by general practitioners used prescribed contraceptives compared with those receiving isotretinoin by specialists., Conclusion: Compliance with the contraceptive use according to a PPP for a teratogenic drug such as isotretinoin is 52%-64%, which is lower than anticipated. Reasons for the low compliance will need to be clarified before further measures can be taken., (Copyright © 2012 John Wiley & Sons, Ltd.)

The combined information of drug exposure and laboratory test results on an individual patient level obtained in daily clinical practice can add important information about the safety of a drug. Thrombocytopenia is a known adverse drug reaction of rituximab, which has already been identified during the preregistration trials, but knowledge on incidence and risk factors in clinical practice is limited. We, therefore, aimed to estimate the incidence and explore the risk factors for the development of rituximab-induced thrombocytopenia (a platelet count, <100 × 10(9) platelets/L) in clinical practice. Ninety patients were eligible for inclusion of which 27 developed thrombocytopenia (cumulative incidence, 30%) within 30 days after administration of rituximab and 18 patients developed grade 3/4 thrombocytopenia (cumulative incidence, 20%). Patients with and without thrombocytopenia were compared to explore risk factors. Patients with a relatively low platelet count (217 vs. 324 × 10(9) /L, P = 0.011) before administration of rituximab had a higher risk for the development of thrombocytopenia, and although not statistically significant, patients treated with rituximab within the oncology setting (OR, 4.7; 95% CI, 1.0-23.3), independent of concomitant use of cytostatics, as compared to the autoimmune diseases and patients with a high platelet distribution width (PDW) (16.1 vs. 15.8, P = 0.051). In conclusion, the incidence of rituximab-induced thrombocytopenia was higher than that identified during the clinical trials. Healthcare professionals should consider thrombocytopenia as a relevant reaction during treatment with rituximab. More frequent monitoring of the platelet count is especially advised in patients treated in the oncology indication and/or with a low platelet count and high PDW., (© 2012 John Wiley & Sons A/S.)

The objective of this study was to analyze to what extent potentially teratogenic medicinal products are dispensed concomitantly with contraceptives. Data on dispensed medicinal products in this population-based study were obtained from the Dutch Foundation for Pharmaceutical Statistics. For over 178 potentially teratogenic medicinal products, concomitant use of contraceptives was assessed. The proportion of potentially teratogenic medicinal products dispensed concomitantly with a contraceptive varied significantly from 40.9% (95% CI 40.7-41.2) in 2005 to 43.4% in 2009 (95% CI 44.2-43.7). Significant differences existed as well between age categories with the lowest proportions of concomitant use of contraceptives for any potentially teratogenic drug in women aged 36 through 45 years (35.0%, 95% CI 34.9-35.1) in comparison to those aged 26 through 35 years (47.1%, 95% CI 46.9-47.3) and 15 through 25 years (53.6%, 95% CI 53.4-53.8). Although our data retrieval did not cover the use of nonpharmacological forms of contraception such as condoms and sterilization and as situations may occur during which the use of drugs with (low) teratogenic potential is a balanced decision, our results raise doubts about the safe use of medicinal products with teratogenic potential.

The effect of Direct Healthcare Professional Communications (DHPCs) informing health-care providers of serious drug safety issues has been questioned. The aim of this study was to evaluate the impact of DHPCs on drug use.Nationwide dispensing data for the period 2000–2008 for new users of 46 drugs with one or more DHPCs were assessed. Impact on short-term volume of use was evaluated with regression models, and the presence of long-term changes in use was evaluated with interrupted time series analyses incorporating preexisting trends. The short-term prescription level was lower post-DHPC in 28 (48.3%) of 58 cases. Twenty (34.5%) DHPCs resulted in long-term changes in use. A long-term mean reduction in use was observed in 26.7% of cases (95% confidence interval, −15.2 to −38.2%).Long-term changes in use were not significantly related to preexisting trends in use. Although short- and long-term decreases in use were observed after only half and a third of DHPCs, respectively, the decrease was substantial.