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The US Food and Drug Administration Adverse Event Reporting System (FAERS) contains over 24 million individual case safety reports (ICSRs). In this research project, we evaluated a natural language processing (NLP) tool’s ability to extract four demographic variables (gender, weight, ethnicity, race) from ICSR narratives. Specificity of the NLP algorithm was over 94% for all demographics, while sensitivity varied between the demographics: 98.6% (gender), 45.5% (weight), 100% (ethnicity), and 85.3% (race). Among ICSRs missing weight, ethnicity, and race in the structured field, few cases had this information in the narrative (>95% missing); consequently, the positive predictive value (PPV) for these three demographics had wide 95% confidence intervals. After NLP implementation, the total number of ICSRs missing gender was reduced by 33% (i.e., NLP identified 472 thousand reports having a gender value in the narrative that was not in the structured field), while the total number of ICSRs missing weight, ethnicity, or race was reduced by less than 4%. This study demonstrated that the implementation of an NLP tool can provide meaningful improvements in the availability of gender information for pharmacovigilance activities conducted with FAERS data. In contrast, NLP tools targeting the extraction of weight, ethnicity, or race from free-text fields have minimal impact largely because the information was infrequently provided by the reporter. Further gains in completeness of these fields must originate from increases in provision of demographic information from the reporter rather than informatic solutions.

INTRODUCTION: Missing age presents a significant challenge when evaluating individual case safety reports (ICSRs) in the FDA Adverse Event Reporting System (FAERS). When age is missing in an ICSR’s structured field, it may be in the report’s free-text narrative. OBJECTIVES: This study aimed to evaluate the performance and assess the potential impact of a rule-based natural language processing (NLP) tool that utilizes a text string search to identify patients’ numerical age from unstructured narratives. METHODS: Using FAERS ICSRs from 2002 to 2018, we evaluated the annual proportion of ICSRs with age missing in the structured field before and after NLP application. Reviewers manually identified patients’ age from ICSR narratives (gold standard) from a random sample of 1500 ICSRs. The gold standard was compared to the NLP-identified age. RESULTS: During the study period, the percentage of ICSRs missing age in the structured field increased from 21.9 to 43.8%. The NLP tool performed well among the random sample: sensitivity 98.5%, specificity 92.9%, positive predictive value (PPV) 94.9%, and F-measure 96.7%. It also performed well for the subset of ICSRs missing age in the structured field; when applied to these cases, NLP identified age for an additional one million ICSRs (10% of the total number of ICSRs from 2002 to 2018) and decreased the percentage of ICSRs missing age to 27% overall. CONCLUSIONS: NLP has potential utility to extract patients’ age from ICSR narratives. Use of this tool would enhance pharmacovigilance and research using FAERS data.

Cutaneous small vessel vasculitis (CSVV) was identified as a safety signal among patients treated with direct oral anticoagulants (DOAC). This study aimed to determine if CSVV risk differed among patients with atrial fibrillation (Afib) who newly initiated warfarin or a DOAC.We identified enrollees aged ≥21 years diagnosed with Afib who newly initiated rivaroxaban, dabigatran, apixaban, and warfarin in the Sentinel Distributed Database from October 19, 2010 to February 29, 2020. We selected and followed patients who did not have evidence of the following in the 183 days prior to initiating treatment: CSVV diagnosis, dispensing of other study drugs, select autoimmune diseases or autoimmune medications, cancer diagnoses or chemotherapeutic treatment, kidney dialysis or transplant, alternative anticoagulation indications, or an institutional (nursing home, hospice, hospital) stay on the treatment initiation date (index date) until CSVV outcome or pre-specified censoring. We conducted 1:1 propensity score matching in six comparisons.CSVV incidence rates for DOACs and warfarin ranged from 3.3 to 5.6 per 10 000-person years in our matched Afib population. The adjusted CSVV hazard ratio (HR) and 95% confidence interval (CI) was 0.94 (0.64, 1.39) for rivaroxaban versus warfarin; 1.17 (0.67, 2.06) for dabigatran vs. warfarin; 0.85 (0.62, 1.16) for apixaban vs. warfarin; 0.86 (0.49, 1.50) for rivaroxaban vs. dabigatran; 0.99 (0.68, 1.45) for rivaroxaban versus apixaban; and 1.70 (0.90, 3.21) for dabigatran versus apixaban.We did not find significant evidence of differential CSVV risk in pair-wise comparisons of DOACs and warfarin.

PURPOSE Erythropoiesis-stimulating agents (ESAs), indicated for treating some patients with chemotherapy-induced anemia (CIA), may increase the risk of tumor progression and mortality. FDA required a Risk Evaluation and Mitigation Strategy (REMS) to mitigate these risks. We assessed REMS impact on ESA administration and red blood cell (RBC) transfusion as surrogate metrics for REMS effectiveness. METHODS Retrospective cohort study including data from January 1, 2006 to December 31, 2018 for beneficiaries ≥65 years enrolled in Centers for Medicare & Medicaid Services (CMS) Medicare Parts A/B with a cancer diagnosis; patients with other indications for ESA use were excluded. Study time was divided into five periods demarcated by issuance of CMS National Coverage Determination (NCD) (Pre-NCD, Pre-REMS) and REMS milestones (Grace Period, REMS, post-REMS). Study outcomes were monthly proportion of chemotherapy episodes (CTEs) with concomitant ESA administration, with post-CTE ESA administration, and with RBC transfusions. RESULTS Of 1 778 855 beneficiaries treated with CT, 308742 received concomitant ESA for CIA. The proportion of CTEs with concomitant and post-CTE ESA administration decreased Pre-REMS (9.0 percentage points [pp] and 3.5 pp, respectively). There were no significant post-REMS changes in the proportion of CTEs with concomitant (0.0 pp) and post-CTE ESA administration (0.1 pp). Fluctuation in RBC transfusions was

BACKGROUND: A previous FDA study reported a favorable benefit risk for apixaban compared with warfarin for stroke prevention in older non-valvular atrial fibrillation (NVAF) patients (≥ 65 years). However, it remains unclear whether this favorable benefit risk persists in other populations including younger users. We examined if a similar benefit risk was observed in the Sentinel System and if it varied by age group. OBJECTIVE: To examine the risk of ischemic stroke, gastrointestinal (GI) bleeding, and intracranial hemorrhage (ICH) in apixaban users compared with warfarin users in Sentinel Distributed Database (SDD). DESIGN AND PARTICIPANTS: A retrospective new user cohort study was conducted among patients, 21 years and older initiating apixaban and warfarin for NVAF, between December 28, 2012, and June 30, 2018, in the SDD. MAIN MEASURES: Cox proportional hazard regression was used to estimate the hazard ratios (HR) and 95% confidence intervals (95% CI) for each outcome (ischemic stroke, GI bleeding, and ICH) in propensity score matched apixaban users compared with the warfarin users. Subgroup analyses by age (21–64, 65–74, and 75+ years) were conducted. KEY RESULTS: After matching, 55.3% and 58.4% (n = 55,038) of the apixaban and warfarin users were included in the main analysis. GI bleeding was the most common outcome. The HR (95% CI) for GI bleeding, ICH, and ischemic stroke in apixaban users compared with warfarin users were 0.57 (0.50–0.66), 0.53 (0.40–0.70), and 0.56 (0.45–0.71) respectively. The reduced risk of these outcomes in apixaban compared with warfarin users persisted across age groups. CONCLUSION: In NVAF patients of all ages initiating either apixaban or warfarin for stroke prevention in the Sentinel System, apixaban was associated with a decreased risk of GI bleeding, ICH, and ischemic stroke compared with warfarin. Among patients less than 65 years of age, apixaban use was associated with a decreased risk of GI bleeding and ischemic stroke. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11606-020-06180-8) contains supplementary material, which is available to authorized users.

Objectives: This study aimed to explore the levels and associations among depressive symptoms, perceived stress, and proinflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor-α) in treatment-naïve patients with breast cancer. Methods: A cross-sectional study with one case and two control groups. Patients with breast cancer, matched patients with depression, and matched healthy women completed questionnaires and blood collection between May 2015 and March 2017. Data were analyzed using the general linear model and linear regression model. Results: The severity of depressive symptoms and perceived stress among patients with breast cancer was significantly higher than that in healthy controls and lower than those in patients with depression. Interleukin-1β was lower in patients with breast cancer than the other two groups. Perceived stress was independently and positively associated with depressive symptoms in patients with breast cancer. There were no significant associations between cytokines and depressive symptoms. Conclusion: Women with breast cancer experienced increased perceived stress prior to anticancer treatment, which was a strong contributor to severe symptoms of depression. Results emphasize the need to screen and identify patients with high perceived stress shortly after the disclosure of the diagnosis of breast cancer. Further research in larger sample is needed to investigate the relationship between proinflammatory cytokines and depressive symptoms.

Purpose To identify and analyze postmarketing cases of complex sleep behaviors (CSBs) resulting in serious injuries, including death, associated with eszopiclone, zaleplon, or zolpidem (Z-drugs). Methods Retrospective analysis of the U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) from 16 December 1992 through 27 February 2018 and medical literature using PubMed and EMBASE. We used random sampling and descriptive statistics. Results We identified 66 cases that met inclusion and exclusion criteria, four of which were identified in the medical literature. Twenty cases reported death and 46 cases reported serious injuries in association with CSBs occurring after the use of a Z-drug. Fatal cases described events, such as carbon monoxide poisoning, drowning, falls, hypothermia, motor vehicle collisions, and apparent completed suicide. Nonfatal cases resulting in serious injuries described events, such as accidental overdoses, falls, gunshot wounds, hypothermia, third-degree burns, and self-injuries or suicide attempts. Twenty-two cases reported a previous episode of a CSB while taking a Z-drug prior to the event reported in this case series. Conclusions The FAERS and medical literature cases support the need for increased awareness of the consequences that may occur because of CSBs associated with the use of Z-drugs. Therefore, to protect public health, regulatory actions were taken, including adding a Boxed Warning, a Contraindication in patients who have experienced a prior episode of a CSB with a Z-drug, and updating the existing Warnings and Precautions. An FDA Drug Safety Communication was also disseminated to alert healthcare professionals and the public of this potential risk.

There have been reports of clinically relevant uterine bleeding events among women of reproductive age exposed to rivaroxaban. The aim of this study was to compare the risk of severe abnormal uterine bleeding (SAUB) resulting in transfusion or surgical intervention among women on rivaroxaban versus apixaban, dabigatran and warfarin. We conducted a retrospective cohort study in the FDA’s Sentinel System (10/2010–09/2015) among females aged 18+ years with venous thromboembolism (VTE), or atrial flutter/fibrillation (AF) who newly initiated a direct oral anticoagulant (DOAC; rivaroxaban, apixaban, dabigatran) or warfarin. We followed women from dispensing date until the earliest of transfusion or surgery following vaginal bleeding, disenrollment, exposure or study end date, or recorded death. We estimated hazard ratios (HRs) using Cox proportional hazards regression via propensity score stratification. Four pairwise comparisons were conducted for each intervention. Overall, there was an increased risk of surgical intervention with rivaroxaban when compared with dabigatran (HR 1.19; 95% CI 1.03–1.38), apixaban (1.23; 1.04–1.47), and warfarin (1.34; 1.22–1.47). No difference in risk for surgical intervention was observed for dabigatran–apixaban comparisons. Increased risk of transfusion was observed for rivaroxaban compared with dabigatran (1.49; 1.03–2.17) only. For patients with no gynecological history, rivaroxaban was associated with risk of surgical intervention compared with dabigatran (1.22; 1.05–1.42), apixaban (1.25; 1.04–1.49), and warfarin (1.36; 1.23–1.50). Our study found increased SAUB risk with rivaroxaban use compared with other DOACs or warfarin. Increased risk with rivaroxaban was present among women without underlying gynecological conditions. Women on anticoagulant therapy should be aware of a risk of SAUB.

Only about half of patients with atrial fibrillation (AF) who are at increased risk for stroke are treated with an oral anticoagulant (OAC), despite guideline recommendations for their use. Educating patients with AF about prevention of stroke with OACs may enable them as agents of change to initiate OAC treatment.To determine whether an educational intervention directed to patients and their clinicians stimulates the use of OACs in patients with AF who are not receiving OACs.The Implementation of a Randomized Controlled Trial to Improve Treatment With Oral Anticoagulants in Patients With Atrial Fibrillation (IMPACT-AFib) trial was a prospective, multicenter, open-label, pragmatic randomized clinical trial conducted from September 25, 2017, to May 1, 2019, embedded in health plans that participate in the US Food and Drug Administration's Sentinel System. It used the distributed database comprising health plan members to identify eligible patients, their clinicians, and outcomes. IMPACT-AFib enrolled patients with AF, a CHA2DS2-VASc (cardiac failure or dysfunction, hypertension, age 65-74 [1 point] or ≥75 years [2 points], diabetes, and stroke, transient ischemic attack or thromboembolism [2 points]-vascular disease, and sex category [female]) score of 2 or more, no evidence of OAC prescription dispensing in the preceding 12 months, and no hospitalization-related bleeding event within the prior 6 months.Randomization to a single mailing of patient and/or clinician educational materials vs control.Analysis was performed on a modified intention-to-treat basis. The primary end point was the proportion of patients with at least 1 OAC prescription dispensed or at least 4 international normalized ratio test results within 1 year of the intervention.Among 47 333 patients, there were 24 909 men (52.6%), the mean (SD) age was 77.9 (9.7) years, mean (SD) CHA2DS2-VASc score was 4.5 (1.7), 22 404 patients (47.3%) had an ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) bleeding risk score of 5 or more, and 8890 patients (18.8%) had a history of hospitalization for bleeding. There were 2328 of 23 546 patients (9.9%) in the intervention group with initiation of OAC at 1 year compared with 2330 of 23 787 patients (9.8%) in the control group (adjusted OR, 1.01 [95% CI, 0.95-1.07]; P = .79).Among a large population with AF with a guideline indication for OACs for stroke prevention who were randomized to a mailed educational intervention or to usual care, there was no clinically meaningful, numerical, or statistically significant difference in rates of OAC initiation. More-intensive interventions are needed to try and address the public health issue of underuse of anticoagulation for stroke prevention among patients with AF.ClinicalTrials.gov Identifier: NCT03259373.

Erythropoiesis-stimulating agents (ESAs), indicated for treating some patients with chemotherapy-induced anemia (CIA), may increase the risk of tumor progression and mortality. FDA required a Risk Evaluation and Mitigation Strategy (REMS) to mitigate these risks. We assessed REMS impact on ESA administration and red blood cell (RBC) transfusion as surrogate metrics for REMS effectiveness.Retrospective cohort study including data from January 1, 2006 to December 31, 2018 for beneficiaries ≥65 years enrolled in Centers for MedicareMedicaid Services (CMS) Medicare Parts A/B with a cancer diagnosis; patients with other indications for ESA use were excluded. Study time was divided into five periods demarcated by issuance of CMS National Coverage Determination (NCD) (Pre-NCD, Pre-REMS) and REMS milestones (Grace Period, REMS, post-REMS). Study outcomes were monthly proportion of chemotherapy episodes (CTEs) with concomitant ESA administration, with post-CTE ESA administration, and with RBC transfusions.Of 1 778 855 beneficiaries treated with CT, 308742 received concomitant ESA for CIA. The proportion of CTEs with concomitant and post-CTE ESA administration decreased Pre-REMS (9.0 percentage points [pp] and 3.5 pp, respectively). There were no significant post-REMS changes in the proportion of CTEs with concomitant (0.0 pp) and post-CTE ESA administration (0.1 pp). Fluctuation in RBC transfusions was4 pp throughout the study period.Medicare beneficiaries showed a substantive decrease in ESA administration after NCD, with minimal impact by the REMS and its removal. Small changes in RBC transfusion over the study period were likely due to a national secular trend.

OBJECTIVE We aimed to provide information through 2015 about use in the United States of estrogen products, including orally and vaginally administered products, in postmenopausal women. METHODS We used prescription claims for US commercial health insurance to calculate, in women 50 years of age or older (n = 12,007,364), the age-standardized and age-specific annual prevalence of estrogen use, by formulation and route of administration, for the period 2006 through 2015. RESULTS The age-standardized annual prevalence of a prescription claim for oral estrogens declined over time, from 83 per 1,000 women in 2007 to 42 per 1,000 women in 2015. The age-standardized annual prevalence of a prescription claim for vaginal estrogens peaked in 2011, at 42 per 1,000 women, before declining to 35 per 1,000 women in 2015. The age-standardized annual prevalence of a prescription claim for transdermal estrogen fluctuated between 15 and 17 per 1,000 women. In age groups under 65 years of age, annual prevalence rates for vaginal rings and inserts declined over the latter half of the study period. CONCLUSIONS Analyses of US prescription claims data between 2006 and 2015 for women 50 years of age or older showed declining use of oral estrogen generally and vaginally administered estrogen products specifically in age groups less than 65 years of age.

Purpose The US Food and Drug Administration's Sentinel system developed tools for sequential surveillance. Methods In patients with non-valvular atrial fibrillation, we sequentially compared outcomes for new users of rivaroxaban versus warfarin, employing propensity score matching and Cox regression. A total of 36 173 rivaroxaban and 79 520 warfarin initiators were variable-ratio matched within 2 monitoring periods. Results Statistically significant signals were observed for ischemic stroke (IS) (first period) and intracranial hemorrhage (ICH) (second period) favoring rivaroxaban, and gastrointestinal bleeding (GIB) (second period) favoring warfarin. In follow-up analyses using primary position diagnoses from inpatient encounters for increased definition specificity, the hazard ratios (HR) for rivaroxaban vs warfarin new users were 0.61 (0.47, 0.79) for IS, 1.47 (1.29, 1.67) for GIB, and 0.71 (0.50, 1.01) for ICH. For GIB, the HR varied by age

Purpose Population-based prescription opioid abuse studies in which one drug is compared to another, or drugs are compared across time, often account for the availability of those drugs in the community. The objective of this investigation is to assess consistency in the relative abuse ratios (RARs) across different approaches for adjusting for drug availability. Methods For the years 2004 through 2010, RARs for each of four prescription opioids (hydrocodone, oxycodone, hydromorphone, and morphine) were calculated using negative binomial regression. Measures of abuse (outcome) were misuse/abuse-related emergency department visits obtained from the Drug Abuse Warning Network. Measures of drug availability (offsets) were drug utilization estimates obtained from IMS Health. Separate regression models were run using each of five measures of drug utilization: unique patients (URDD), prescriptions dispensed (RX), tablets dispensed (TD), kilograms (KGs) sold, and morphine-equivalents (MEs) of kilograms sold. These results were compared for consistency. Results Aside from oxycodone-combination products, across molecules, RARs adjusted by RXs, TDs, and URDDs were generally similar to each other while RARs adjusted by KGs and MEs were different. For example, compared to hydrocodone, oxycodone had statistically significantly increased RARs of 3.6 (95%CI: 2.0–6.5), 3.5 (95%CI: 1.9–6.4), and 2.7 (95%CI: 1.5–5.0) when adjusted by URDDs, RXs, and TDs, respectively, but not when adjusted by KGs or MEs. Conclusions Different drug utilization adjustment approaches may yield inconsistent RAR estimates in population-based prescription opioid abuse analyses. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Depressive symptoms are common among kidney transplantation recipients. Previous studies have reported that fatigue and rumination are risk factors for depressive symptoms. To date, the underlying mechanisms of fatigue, rumination, and depressive symptoms among kidney transplantation recipients remain unclear. This study aimed to assess the prevalence of depressive symptoms and investigate whether rumination mediates the association between fatigue and depressive symptoms among kidney transplantation recipients.Cross-sectional study.The study of 207 kidney transplantation recipients with an average age of 44.5 years was conducted from January 2017-July 2017. Sociodemographic and clinical characteristics, fatigue, rumination, and depressive symptoms data were collected. For the descriptive analysis, Pearson correlations and mediation analysis based on the PROCESS macro were used.The prevalence of depressive symptoms among kidney transplantation recipients was 21.7%. Rumination mediated the association between fatigue and depressive symptoms and the indirect effect was 0.19 (95% confidence interval: 0.10-0.28).Depressive symptoms were highly prevalent among kidney transplantation recipients. Rumination exerts a mediating role between fatigue and depressive symptoms.This study alerts physicians and nurses for the importance of considering the mental health of these patients and contributes to the development of effective depression management interventions.目的: 抑郁症状在肾移植接受者中非常常见。以往研究表明疲倦和反刍性沉思是患上抑郁症状的危险因素。迄今为止,肾移植者的疲倦、反刍性沉思和抑郁症状的潜在机制仍不清楚。此研究旨在评估抑郁症状的患病率,并探讨反刍性沉思是否能介导疲倦和抑郁症状之间的关系。 设计: 横断面研究 方法: 自2017年1月至2017年7月,我们对对207名平均年龄为44.5岁的肾脏移植者进行了研究,并且收集了社会人口统计学和临床特征,疲劳,反刍性沉思和抑郁症状数据。对于描述性分析,我们使用了Pearson相关系数以及基于PROCESS宏的中介分析。 结果: 肾移植者中,抑郁症状的患病率为21.7%。反刍性沉思对疲倦和抑郁症状之间的关系起到了中介作用,间接效应为0.19(95%置信区间:0.10-0.28)。 结论: 抑郁症状在肾移植者中非常普遍。反刍性沉思在疲倦和抑郁症状之间起到了中介作用。 影响: 本研究提醒医生和护士考虑这类患者心理健康的重要性,并有助于制定有效的抑郁症治疗干预措施。.

Observational studies provide a core resource in assessing post-market drug safety and effectiveness. Propensity scores are a predominant method for confounding adjustment to achieve unbiased estimation of average treatment effects in observational data. However, the use of propensity score methods has been limited to comparing two treatment groups, while medical situations frequently present with multiple treatment options. Inverse probability of treatment weighting (IPTW) is a popular propensity score adjustment method, but its performance degrades with decreased positivity leading to extreme weights, a problem that can be amplified with multiple treatment groups. Meanwhile, regression on a spline of the propensity score has shown favorable performance compared to other propensity score methods in recent studies involving two treatments. This project utilizes a simulation study to compare IPTW and propensity score splines as adjustment methods in a three-treatment setting. We test a variety of spline methods, including natural cubic splines with varying numbers of interior knots, and thin-plate regression splines. We vary several parameters across simulations, including the degree of propensity score overlap among treatment groups, treatment prevalence, outcome prevalence, and true marginal relative risk. We assess methods based on their bias, root mean squared error, and coverage of the true marginal relative risk across simulations. We find that all methods perform similarly well when there is good propensity score distribution overlap. However, with even moderate decrease in overlap or low outcome prevalence, IPTW produces more biased estimates and higher variance than propensity score splines. Low treatment prevalence or unequal treatment prevalences across groups also worsens IPTW performance. Overall, a natural cubic spline with a relatively small number of interior knots provides good performance across a range of simulations.

Background— The comparative safety of dabigatran versus warfarin for treatment of nonvalvular atrial fibrillation in general practice settings has not been established. Methods and Results— We formed new-user cohorts of propensity score–matched elderly patients enrolled in Medicare who initiated dabigatran or warfarin for treatment of nonvalvular atrial fibrillation between October 2010 and December 2012. Among 134 414 patients with 37 587 person-years of follow-up, there were 2715 primary outcome events. The hazard ratios (95% confidence intervals) comparing dabigatran with warfarin (reference) were as follows: ischemic stroke, 0.80 (0.67–0.96); intracranial hemorrhage, 0.34 (0.26–0.46); major gastrointestinal bleeding, 1.28 (1.14–1.44); acute myocardial infarction, 0.92 (0.78–1.08); and death, 0.86 (0.77–0.96). In the subgroup treated with dabigatran 75 mg twice daily, there was no difference in risk compared with warfarin for any outcome except intracranial hemorrhage, in which case dabigatran risk was reduced. Most patients treated with dabigatran 75 mg twice daily appeared not to have severe renal impairment, the intended population for this dose. In the dabigatran 150-mg twice daily subgroup, the magnitude of effect for each outcome was greater than in the combined-dose analysis. Conclusions— In general practice settings, dabigatran was associated with reduced risk of ischemic stroke, intracranial hemorrhage, and death and increased risk of major gastrointestinal hemorrhage compared with warfarin in elderly patients with nonvalvular atrial fibrillation. These associations were most pronounced in patients treated with dabigatran 150 mg twice daily, whereas the association of 75 mg twice daily with study outcomes was indistinguishable from warfarin except for a lower risk of intracranial hemorrhage with dabigatran.

We address several questions relating to the use of standard regression and Structural Nested Mean Model (SNMM) approach (e. g., Ten Have et al. 2007) to analyze post-randomization effect modifiers of the intent-to-treat effect of a randomized intervention on a subsequent outcome, which has not been well examined. We show through simulations that the SNMM performs better with respect to bias of estimates of the intervention and interaction effects than does the corresponding standard interaction approach when the baseline intervention is randomized and the post-randomization factors are subject to confounding, and even when there is no association between the intervention and effect modifier. However, causal inference under the SNMM makes untestable assumptions that the causal contrasts do not vary across observed levels of the intervention and post-randomization factor. In addition, the precision of the SNMM-based estimators depends on the effect of the randomized intervention on the post-randomization factor varying across baseline covariate combinations. These issues and methods are illustrated with the application of the standard and causal methods to a randomized cognitive therapy (CT) trial, for which there is a conceptual model of negative cognitive styles or distortions impacted by CT but then in turn modifying the effect of CT on subsequent suicide ideation and social problem solving outcomes.

OBJECTIVE The cardiovascular safety of saxagliptin, a dipeptidyl-peptidase 4 inhibitor, compared with other antihyperglycemic treatments is not well understood. We prospectively examined the association between saxagliptin use and acute myocardial infarction (AMI). RESEARCH DESIGN AND METHODS We identified patients aged ≥18 years, starting from the approval date of saxagliptin in 2009 and continuing through August 2014, using data from 18 Mini-Sentinel data partners. We conducted seven sequential assessments comparing saxagliptin separately with sitagliptin, pioglitazone, second-generation sulfonylureas, and long-acting insulin, using disease risk score (DRS) stratification and propensity score (PS) matching to adjust for potential confounders. Sequential testing kept the overall chance of a false-positive signal below 0.05 (one-sided) for each pairwise comparison. RESULTS We identified 82,264 saxagliptin users and more than 1.5 times as many users of each comparator. At the end of surveillance, the DRS-stratified hazard ratios (HRs) (95% CI) were 1.08 (0.90–1.28) in the comparison with sitagliptin, 1.11 (0.87–1.42) with pioglitazone, 0.79 (0.64–0.98) with sulfonylureas, and 0.57 (0.46–0.70) with long-acting insulin. The corresponding PS-matched HRs were similar. Only one interim analysis of 168 analyses met criteria for a safety signal: the PS-matched saxagliptin-pioglitazone comparison from the fifth sequential analysis, which yielded an HR of 1.63 (1.12–2.37). This association diminished in subsequent analyses. CONCLUSIONS We did not find a higher AMI risk in saxagliptin users compared with users of other selected antihyperglycemic agents during the first 5 years after U.S. Food and Drug Administration approval of the drug.

The construction of optimal experimental designs for regression models requires knowledge of the information matrix of a single observation. The latter can be found if the elemental information matrix corresponding to the distribution of the response is known. We present tables of elemental information matrices for distributions that are often used in statistical work. The tables contain matrices for one- and two-parameter distributions. Additionally we describe multivariate normal and multinomial cases. The parameters of response distributions can themselves be parameterized to provide dependence on explanatory variables, thus leading to regression formulations for wide classes of models. We present essential results from optimal experimental design and illustrate our approach with a few examples including bivariate binary responses and gamma regression.

Nonvitamin K antagonist oral anticoagulants (NOACs) are alternatives to warfarin in patients with nonvalvular atrial fibrillation. Randomized trials compared NOACs with warfarin, but none have compared individual NOACs against each other for safety and effectiveness.We performed a retrospective new-user cohort study of patients with nonvalvular atrial fibrillation enrolled in US Medicare who initiated warfarin (n = 183,318), or a standard dose of dabigatran (150 mg twice daily; n = 86,198), rivaroxaban (20 mg once daily; n = 106,389), or apixaban (5 mg twice daily; n = 73,039) between October 2010 and September 2015. Propensity score-adjusted Cox proportional hazards regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the outcomes of thromboembolic stroke, intracranial hemorrhage, major extracranial bleeding, and all-cause mortality, comparing each NOAC with warfarin, and with each other NOAC.Compared with warfarin, each NOAC was associated with reduced risks of thromboembolic stroke (20%-29% reduction; P = .002 [dabigatran], P0.001 [rivaroxaban, apixaban]), intracranial hemorrhage (35%-62% reduction; P0.001 [each NOAC]), and mortality (19%-34% reduction; P.001 [each NOAC]). The NOACs were similar for thromboembolic stroke but rivaroxaban was associated with increased risks of intracranial hemorrhage (vs dabigatran: HR = 1.71; 95% CI, 1.35-2.17), major extracranial bleeding (vs dabigatran: HR = 1.32; 95% CI, 1.21-1.45; vs apixaban: HR = 2.70; 95% CI, 2.38-3.05), and death (vs dabigatran: HR = 1.12; 95% CI, 1.01-1.24; vs apixaban: HR = 1.23; 95% CI, 1.09-1.38). Dabigatran was associated with reduced risk of intracranial hemorrhage (HR = 0.70; 95% CI ,0.53-0.94) and increased risk of major extracranial bleeding (HR = 2.04; 95% CI, 1.78-2.32) compared with apixaban.Among patients treated with standard-dose NOAC for nonvalvular atrial fibrillation and warfarin users with similar baseline characteristics, dabigatran, rivaroxaban, and apixaban were associated with a more favorable benefit-harm profile than warfarin. Among NOAC users, dabigatran and apixaban were associated with a more favorable benefit-harm profile than rivaroxaban.

In dose-finding clinical studies, it is common that multiple endpoints are of interest. For instance, in phase I/II studies, efficacy and toxicity are often the primary endpoints, which are observed simultaneously and which need to be evaluated together. Motivated by this, we confine ourselves to bivariate responses and focus on the most analytically difficult case: a mixture of continuous and categorical responses. We adopt the bivariate probit dose–response model and quantify our goal by a utility function. We study locally optimal designs, two-stage optimal designs, and fully adaptive designs under different ethical and cost constraints in the experiments. We assess the performance of two-stage designs and fully adaptive designs via simulations. Our simulations suggest that the two-stage designs are as efficient as and may be more efficient than the fully adaptive designs if there is a moderate sample size in the initial stage. In addition, two-stage designs are easier to construct and implement and thus can be a useful approach in practice. Copyright © 2011 John Wiley & Sons, Ltd.

Background Dabigatran (150 mg twice daily) has been associated with lower rates of stroke than warfarin in trials of atrial fibrillation, but large-scale evaluations in clinical practice are limited. Objective To compare incidence of stroke, bleeding, and myocardial infarction in patients receiving dabigatran versus warfarin in practice. Design Retrospective cohort. Setting National U.S. Food and Drug Administration Sentinel network. Patients Adults with atrial fibrillation initiating dabigatran or warfarin therapy between November 2010 and May 2014. Measurements Ischemic stroke, intracranial hemorrhage, extracranial bleeding, and myocardial infarction identified from hospital claims among propensity score-matched patients starting treatment with dabigatran or warfarin. Results Among 25 289 patients starting dabigatran therapy and 25 289 propensity score-matched patients starting warfarin therapy, those receiving dabigatran did not have significantly different rates of ischemic stroke (0.80 vs. 0.94 events per 100 person-years; hazard ratio [HR], 0.92 [95% CI, 0.65 to 1.28]) or extracranial hemorrhage (2.12 vs. 2.63 events per 100 person-years; HR, 0.89 [CI, 0.72 to 1.09]) but were less likely to have intracranial bleeding (0.39 vs. 0.77 events per 100 person-years; HR, 0.51 [CI, 0.33 to 0.79]) and more likely to have myocardial infarction (0.77 vs. 0.43 events per 100 person-years; HR, 1.88 [CI, 1.22 to 2.90]). However, the strength and significance of the association between dabigatran use and myocardial infarction varied in sensitivity analyses and by exposure definition (HR range, 1.13 [CI, 0.78 to 1.64] to 1.43 [CI, 0.99 to 2.08]). Older patients and those with kidney disease had higher gastrointestinal bleeding rates with dabigatran. Limitation Inability to examine outcomes by dabigatran dose (unacceptable covariate balance between matched patients) or quality of warfarin anticoagulation (few patients receiving warfarin had available international normalized ratio values). Conclusion In matched adults with atrial fibrillation treated in practice, the incidences of stroke and bleeding with dabigatran versus warfarin were consistent with those seen in trials. The possible relationship between dabigatran and myocardial infarction warrants further investigation. Primary funding source U.S. Food and Drug Administration.

A novel amphiphilic ABCBA-type pentablock copolymer with properties that are sensitive to temperature and pH, poly(2-dimethylaminoethyl methacrylate)block-poly(2,2,2-trifluoroethyl methacrylate)-block-poly(e-caprolactone)-block-poly(2,2,2-trifluoroethyl methacrylate)-block-poly(2-dimethylaminoethyl methacrylate) (PDMAEMA-b-PTFEMA-b-PCL-b-PTFEMA-b-PDMAEMA), was synthesized via consecutive atom transfer radical polymerizations (ATRPs). The copolymers obtained were characterized by gel permeation chromatography (GPC) and 1 H nuclear magnetic resonance (NMR) spectroscopy, respectively. The aggregation behaviors of the pentablock copolymers in aqueous solution with different pH (pH = 4.0, 7.0 and 8.5) were studied. Transmission electron microscopic images revealed that spherical micelles from self-assembly of the pentablock copolymer were prevalent in all cases. The mean diameters of these micelles increased from 34, 46, to 119 nm when the pH of the aqueous solution decreased from 8.5, 7.0, to 4.0, respectively.

A single nucleotide polymorphism, � 160C/A, has been identified in the promoter region of the E-cadherin gene and has been shown to alter its transcriptional activity. To assess susceptibility of � 160A allele carriers to seven types of cancers, the authors conducted a comprehensive meta-analysis, up to November 2006, of 26 case-control studies comprising 7,042 cases and 7,011 controls. Pooled odds ratios and 95% confidence intervals were calculated by using the random-effects model. Publication bias, subgroup, and sensitivity analyses were also performed, which showed that � 160A allele carriers, compared with noncarriers, had about a 17–19% increased risk of several invasive/ metastatic tumors. Analyses of various types of cancers revealed that, in Europeans, the � 160AA homozygote was associated with an increased risk of urothelial cancer, carriers of � 160A were at increased risk of lung and prostate cancers, and carriers of � 160A with gastric cancer were found to suffer a significantly increased risk, whereas their Asian counterparts seemed to be tolerant. No evidence was found that the � 160A allele predisposed its carriers to breast, colorectal, or esophageal cancers. These findings indicate that � 160A of the E-cadherin gene is emerging as a low-penetrance tumor susceptibility allele for the development of gastric, lung, prostate, and urothelial cancers.

Uncovering genetic control of variation in ethanol tolerance in natural populations of yeast Saccharomyces cerevisiae is essential for understanding the evolution of fermentation, the dominant lifestyle of the species, and for improving efficiency of selection for strains with high ethanol tolerance, a character of great economic value for the brewing and biofuel industries. To date, as many as 251 genes have been predicted to be involved in influencing this character. Candidacy of these genes was determined from a tested phenotypic effect following gene knockout, from an induced change in gene function under an ethanol stress condition, or by mutagenesis. This article represents the first genomics approach for dissecting genetic variation in ethanol tolerance between two yeast strains with a highly divergent trait phenotype. We developed a simple but reliable experimental protocol for scoring the phenotype and a set of STR/SNP markers evenly covering the whole genome. We created a mapping population comprising 319 segregants from crossing the parental strains. On the basis of the data sets, we find that the tolerance trait has a high heritability and that additive genetic variance dominates genetic variation of the trait. Segregation at five QTL detected has explained ∼50% of phenotypic variation; in particular, the major QTL mapped on yeast chromosome 9 has accounted for a quarter of the phenotypic variation. We integrated the QTL analysis with the predicted candidacy of ethanol resistance genes and found that only a few of these candidates fall in the QTL regions.

Condor provides high throughput computing by leveraging idle-cycles on off-the-shelf desktop machines. It also supports flocking, a mechanism for sharing resources among Condor pools. Since Condor pools distributed over a wide area can have dynamically changing availability and sharing preferences, the current flocking mechanism based on static configurations can limit the potential of sharing resources across Condor pools. This paper presents a technique for resource discovery in distributed Condor pools using peer-to-peer mechanisms that are self-organizing, fault-tolerant, scalable, and locality-aware. Locality-awareness guarantees that applications are not shipped across long distances when nearby resources are available. Measurements using a synthetic job trace show that self-organized flocking reduces the maximum job wait time in queue for a heavily loaded pool by a factor of 10 compared to without flocking. Simulations of 1000 Condor pools are also presented and the results confirm that our technique discovers and utilizes nearby resources in the physical network.

Allozyme and PCR-based molecular markers have been widely used to investigate genetic diversity and population genetic structure in autotetraploid species. However, an empirical but inaccurate approach was often used to infer marker genotype from the pattern and intensity of gel bands. Obviously, this introduces serious errors in prediction of the marker genotypes and severely biases the data analysis. This article developed a theoretical model to characterize genetic segregation of alleles at genetic marker loci in autotetraploid populations and a novel likelihood-based method to estimate the model parameters. The model properly accounts for segregation complexities due to multiple alleles and double reduction at autotetrasomic loci in natural populations, and the method takes appropriate account of incomplete marker phenotype information with respect to genotype due to multiple-dosage allele segregation at marker loci in tetraploids. The theoretical analyses were validated by making use of a computer simulation study and their utility is demonstrated by analyzing microsatellite marker data collected from two populations of sycamore maple (Acer pseudoplatanus L.), an economically important autotetraploid tree species. Numerical analyses based on simulation data indicate that the model parameters can be adequately estimated and double reduction is detected with good power using reasonable sample size.

An increased risk of depressive symptoms has been associated with the transition to menopause, but the risk of depressive symptoms in the early postmenopausal years has not been well characterized.To identify within-woman changes in depressive symptoms during a 14-year period around menopause, determine associations of a history of depression with the pattern of depressive symptoms, and evaluate the rate of change in reproductive hormones as predictors of depressive symptoms following menopause.A randomly identified, population-based sample in Philadelphia County, Pennsylvania, of 203 late-reproductive-age women who were premenopausal at baseline and reached natural menopause.Center for Epidemiologic Studies Depression Scale.The prevalence of high scores on the Center for Epidemiologic Studies Depression Scale decreased from 10 years before to 8 years after the final menstrual period (FMP), with a decrease of approximately 15% of baseline per year (odds ratio, 0.85; 95% CI, 0.81-0.89; P .001). Relative to the FMP, the risk of depressive symptoms was higher in the years before and lower in the years after the FMP. Among women with a history of depression, the likelihood of depressive symptoms was more than 13 times greater overall and 8 times greater after menopause compared with women with no depression history. Among women who first experienced depressive symptoms approaching menopause, the risk of depressive symptoms declined after the FMP, with a significantly lower risk the second year after menopause. The risk of depressive symptoms after menopause decreased by 35% for each unit (SD) increase before the FMP in the log rate of change of follicle-stimulating hormone (odds ratio, 0.65; 95% CI, 0.46-0.91; P = .01).The FMP was pivotal in the overall pattern of decreasing depressive symptoms in midlife women, with higher risk before and lower risk after the FMP. A history of depression strongly increased the risk both before and after menopause. Women who had no history of depression before the menopause transition had a low risk of depressive symptoms 2 or more years after the FMP.

Modeling linkage disequilibria (LD) between genes usually observed in admixed natural populations has been shown an effective approach in high-resolution mapping of disease genes in humans. A prerequisite to obtain accurate estimation of recombination fraction between genes at a marker locus and the disease locus using the approach is a reliable prediction of the proportion of the admixture populations. The present study suggested the use of gene frequencies to predict the estimate of the admixture proportion based on the observation that the gene frequencies are much more stable quantities than the haplotype frequencies over evolution of the population. In this paper, we advanced the theory and methods by which the decay rate of nonlinear term of LD in admixed population may be used to estimate the recombination fraction between the genes. Theoretical analysis and simulation study indicate that, the larger the difference of gene frequencies between parental populations and the more closely the admixture proportion approaches 0.5, the more important the nonlinear term of the LD in the admixed population, and hence the more informative such admixed populations in the high-resolution gene mapping practice.

Understanding linkage disequilibrium (LD) created in admixed population and the rate of decay in the disequilibrium over evolution is an important subject in population genetics theory and in disease gene mapping in human populations. The present study represents the theoretical investigation of effects of gene frequencies, levels of LD and admixture proportions of donor populations on the evolutionary dynamics of the LD of the admixed population. We examined the conditions under which the admixed population reached linkage equilibrium or the peak level of the LD. The study reveals the inappropriateness in approximating the dynamics of the LD generated by population admixture by the commonly used formula in literature. An appropriate equation for the dynamics is proposed. The distinct feature of the newly suggested formula is that the value of the nonlinear component of the LD remains constant in the first generation of the population evolution. Comparison between the predicted disequilibrium dynamics shows that the error will be caused by using the old formula, and thus resulting in a misguidance in using the evolutionary information of the admixed population in gene mapping.