Search

Importance: Off-label use of prescription drugs has been identified as an important contributor to preventable adverse drug events (ADEs) in children. Despite concerns regarding adverse outcomes, to date, no systematic investigation of the effects of off-label drug use in adult populations has been performed., Objective: To monitor and evaluate off-label use of prescription drugs and its effect on ADEs in an adult population., Design, Setting, and Participants: A cohort of 46,021 patients who received 151,305 incident prescribed drugs was assembled from primary care clinics in Quebec, Canada, using the Medical Office of the XXIst Century electronic health record, which supports documentation of treatment indications and treatment outcomes. Prescriptions dispensed from January 1, 2005, through December 30, 2009, were followed up from the date of the prescription to the date the drug use was discontinued, the end of treatment, or the end of follow-up (December 30, 2010). Data were analyzed from January 5, 2012, to March 15, 2015., Exposures: Off-label prescription drug use with and without strong scientific evidence., Main Outcomes and Measures: Adverse drug events in off-label use with and without strong scientific evidence. Analysis used multivariate marginal Cox proportional hazards regression for clustered data with the drug as the unit of analysis., Results: A total of 3484 ADEs were found in the 46,021 study patients, with an incidence rate of 13.2 per 10,000 person-months. The rate of ADEs for off-label use (19.7 per 10,000 person-months) was higher than that for on-label use (12.5 per 10,000 person-months) (adjusted hazard ratio [AHR], 1.44; 95% CI, 1.30-1.60). Off-label use lacking strong scientific evidence had a higher ADE rate (21.7 per 10,000 person-months) compared with on-label use (AHR, 1.54; 95% CI, 1.37-1.72). However, off-label use with strong scientific evidence had the same risk for ADEs as on-label use (AHR, 1.10; 95% CI, 0.88-1.38). The risks for ADEs were higher for drugs approved from 1981 to 1995 (14.4 per 10,000 person-months; AHR, 1.62; 95% CI, 1.45-1.80) and for those used by women (14.3 per 10,000 person-months; AHR, 1.17; 95% CI, 1.06-1.28), patients receiving 5 to 7 drugs (12.1 per 10,000 person-months; AHR, 3.23; 95% CI, 2.66-3.92), and patients receiving cardiovascular drugs (15.9 per 10,000 person-months; AHR, 3.30; 95% CI, 2.67-4.08) and anti-infectives (66.2 per 10,000 person-months; AHR, 6.33; 95% CI, 4.58-8.76). Patients with a 1-unit increase in the continuity of care index had a 19% increase in ADEs (AHR, 1.19; 95% CI, 1.12-1.26)., Conclusions and Relevance: Off-label use of prescription drugs is associated with ADEs. Caution should be exercised in prescribing drugs for off-label uses that lack strong scientific evidence. Future electronic health records should be designed to enable postmarket surveillance of treatment indications and treatment outcomes to monitor the safety of on- and off-label uses of drugs.

Background: Off-label prescribing may lead to adverse drug events. Little is known about its prevalence and determinants resulting from challenges in documenting treatment indication., Methods: We used the Medical Office of the XXI Century electronic health record network in Quebec, Canada, where documentation of treatment indication is mandatory. One hundred thirteen primary care physicians wrote 253 347 electronic prescriptions for 50 823 patients from January 2005 through December 2009. Each drug indication was classified as on-label or off-label according to the Health Canada drug database. We identified off-label uses lacking strong scientific evidence. Alternating logistic regression was used to estimate the association between off-label use and drug, patient, and physician characteristics., Results: The prevalence of off-label use was 11.0%; of the off-label prescriptions, 79.0% lacked strong scientific evidence. Off-label use was highest for central nervous system drugs (26.3%), including anticonvulsants (66.6%), antipsychotics (43.8%), and antidepressants (33.4%). Drugs with 3 or 4 approved indications were associated with less off-label use compared with drugs with 1 or 2 approved indications (6.7% vs 15.7%; adjusted odds ratio [AOR], 0.44; 95% CI, 0.41-0.48). Drugs approved after 1995 were prescribed off-label less often than were drugs approved before 1981 (8.0% vs 17.0%; AOR, 0.46; 95% CI, 0.42-0.50). Patients with a Charlson Comorbidity Index of 1 or higher had lower off-label use than did patients with an index of 0 (9.6% vs 11.7%; AOR, 0.94; 95% CI, 0.91-0.97). Physicians with evidence-based orientation were less likely to prescribe off-label (AOR, 0.93; 95% CI, 0.88-0.99), a 7% reduction per 5 points in the evidence section of the Evidence-Practicality-Conformity Scale., Conclusions: Off-label prescribing is common and varies by drug, patient, and physician characteristics. Electronic prescribing should document treatment indication to monitor off-label use.

Background: Comparing trauma centers in terms of patient survival is a key element of performance evaluation. The current standard in trauma center profiling is based on Ordinary Logistic Regression (OLR). However, OLR does not take account of the hierarchical structure of trauma systems. Hierarchical Logistic Regression (HLR) accounts for the clustering of patients within hospitals and is therefore more theoretically appropriate. The objective of this study was to evaluate whether HLR generates different profiling results than OLR., Methods: The study was based on the Quebec Trauma Registry with mandatory participation of all 59 designated trauma centers in the province of Quebec, uniform inclusion criteria, and standardized data collection methods. Trauma profiling was based on adjusted odds ratios, which represent the odds that a patient will die in a specific hospital compared with an "average" hospital. Risk adjustment was performed with the Trauma Risk Adjustment Model score. Hospitals were ranked according to odds ratio, and outliers were identified by comparing each hospital with all other hospitals. Hospital ranks and statistical outliers generated by OLR and HLR were compared., Results: The study population comprised 83,504 patients including 4,731 hospital deaths (5.7%). OLR identified 11 hospitals as statistical outliers whereas HLR flagged only four of these hospitals as outliers. In addition, 54 of 59 hospitals changed ranks and 24 hospitals changed by more than five ranks when HLR replaced OLR., Conclusions: This study shows that replacing OLR with HLR has an important impact on the results of hospital profiling. Along with the many theoretical advantages of HLR, these results support the adoption of hierarchical modeling as the standard method for trauma center profiling.

Background: Organized trauma systems are designed to improve the quality and efficiency of trauma care. Several studies have reported mortality reductions during or immediately after implementation of a trauma system but little data are available on long-term trends. The aim of this study was to evaluate the long-term trend in risk-adjusted mortality in a mature inclusive trauma system., Methods: The trauma system of the province of Quebec, Canada, was implemented in 1992 and completed in 1996. Data were drawn from the Quebec Trauma Registry with mandatory participation of all 59 centres, uniform inclusion criteria, and standardized data collection and validation procedures. Temporal trends from 1999 to 2006 were evaluated using adjusted estimates of hospital mortality generated with a random-intercept hierarchical logistic regression model. Estimates were adjusted using the Trauma Risk Adjustment Model (TRAM) score., Results: The study population comprised 88,235 patients, including 4731 hospital deaths (5.4%). Crude mortality risk varied between 5.2% in 1999 and 4.6% in 2006. Adjusted mortality risk remained stable between 1999 and 2002, but a statistically significant decrease of 4.6% per year (95% CI = 0.9-8.5) was observed between 2002 and 2006., Conclusions: The risk of hospital mortality in the Quebec trauma system decreased by 24% between 2002 and 2006. Results suggest that as inclusive and regionalized trauma systems mature, they may provide better care to trauma victims. Further research should attempt to identify determinants of the observed decrease within the system and evaluate quality of life among survivors.

Background: Adverse drug reaction reports used in pharmacosurveillance often lack complete information on treatment indication that is important for benefit-risk analyses and clinical and regulatory decision making. A systematic documentation of treatment indication using electronic prescribing applications provides an opportunity to develop new pharmacosurveillance tools that will allow evaluation of drugs by weighing benefits and risks for specific indications, and evaluate off-label prescribing. In addition, interfacing indications with reminders and clinical guidelines can enhance clinical decision making. We investigated the validity of treatment indications documented using an electronic prescribing system at the time of prescribing., Objectives: To determine the sensitivity and positive predictive value (PPV) of an electronic prescribing system in documenting treatment indications at the time of drug prescribing, and to investigate the use of treatment indication data to evaluate off-label prescribing in primary-care practice., Study Design and Setting: We prospectively assessed the validity of documenting treatment indication using an electronic prescribing system by comparing it with treatment indications documented by physician-facilitated medical chart review ('gold standard'). Sensitivity and PPV were evaluated in 338 patients of 22 community-based primary-care physicians in Quebec, Canada, in 2006., Results: The sensitivity of the electronic prescribing system in documenting treatment indication was 98.5% (95% CI 96.5, 99.5) and the PPV of the system in accurately identifying the treatment indication was 97.0% (95% CI 94.2, 98.6). The treatment indication data collected using this system allowed assessment of off-label prescribing., Conclusions: The electronic prescribing system offers a valid method for documenting treatment indication at the time of prescribing. Our results provide strong evidence to support incorporating mandatory recording of treatment indication in integrated electronic prescribing systems to provide a critical piece of information for the evaluation of safety and effectiveness of drugs.

Background: Less than 75% of people prescribed antihypertensive medication are still using treatment after 6 months. Physicians determine treatment, educate patients, manage side effects, and influence patient knowledge and motivation. Although physician communication ability likely influences persistence, little is known about the importance of medical management skills, even though these abilities can be enhanced through educational and practice interventions. The purpose of this study was to determine whether a physician's medical management and communication ability influence persistence with antihypertensive treatment., Methods: This was a population-based study of 13,205 hypertensive patients who started antihypertensive medication prescribed by a cohort of 645 physicians entering practice in Quebec, Canada, between 1993 and 2007. Medical Council of Canada licensing examination scores were used to assess medical management and communication ability. Population-based prescription and medical services databases were used to assess starting therapy, treatment changes, comorbidity, and persistence with antihypertensive treatment in the first 6 months., Results: Within 6 months after starting treatment, 2926 patients (22.2%) had discontinued all antihypertensive medication. The risk of nonpersistence was reduced for patients who were treated by physicians with better medical management (odds ratio per 2-SD increase in score, 0.74; 95% confidence interval, 0.63-0.87) and communication (0.88; 0.78-1.00) ability and with early therapy changes (odds ratio, 0.45; 95% confidence interval, 0.37-0.54), more follow-up visits, and nondiuretics as the initial choice of therapy. Medical management ability was responsible for preventing 15.8% (95% confidence interval, 7.5%-23.3%) of nonpersistence., Conclusion: Better clinical decision-making and data collection skills and early modifications in therapy improve persistence with antihypertensive therapy.

Background: Studies suggest that sex differences in blood pressure (BP) are established early in life. Sex differences in BP increases that occur during adolescence may be due to differences in changes in anthropometric characteristics., Methods: Using sex-specific individual growth models, we assessed the effect of height, body mass index (BMI; kg/m), waist circumference, and triceps and subscapular skinfold thickness on changes in systolic BP in a cohort of 1293 adolescents in Montreal, Canada. BP and anthropometry were assessed biannually (1999/2000, 2002, 2004) at mean ages 12.8, 15.2, and 17.0., Results: On average, systolic BP increased by 11.1 mm Hg in boys and 3.2 mm Hg in girls during 5 years. Changes in height explained half of the overall increase in systolic BP in boys and virtually all of the increase in systolic BP in girls. No meaningful sex differences were observed in the association of changes in BMI, waist circumference, and triceps and subscapular skinfold thickness with systolic BP change during 5 years. Increases in 1 BMI unit, 1 cm waist circumference, or 1 mm triceps or subscapular skinfold thickness were associated with increases of 0.7, 0.24, 0.3, and 0.4 mm Hg systolic BP, respectively., Conclusions: Although sex differences in mean systolic BP changes during adolescence were largely attributable to differences in gains in height, the effect of gaining weight or body fat on systolic BP change was similar in boys and girls.

Context: Poor patient-physician communication increases the risk of patient complaints and malpractice claims. To address this problem, licensure assessment has been reformed in Canada and the United States, including a national standardized assessment of patient-physician communication and clinical history taking and examination skills., Objective: To assess whether patient-physician communication examination scores in the clinical skills examination predicted future complaints in medical practice., Design, Setting, and Participants: Cohort study of all 3424 physicians taking the Medical Council of Canada clinical skills examination between 1993 and 1996 who were licensed to practice in Ontario and/or Quebec. Participants were followed up until 2005, including the first 2 to 12 years of practice., Main Outcome Measure: Patient complaints against study physicians that were filed with medical regulatory authorities in Ontario or Quebec and retained after investigation. Multivariate Poisson regression was used to estimate the relationship between complaint rate and scores on the clinical skills examination and traditional written examination. Scores are based on a standardized mean (SD) of 500 (100)., Results: Overall, 1116 complaints were filed for 3424 physicians, and 696 complaints were retained after investigation. Of the physicians, 17.1% had at least 1 retained complaint, of which 81.9% were for communication or quality-of-care problems. Patient-physician communication scores for study physicians ranged from 31 to 723 (mean [SD], 510.9 [91.1]). A 2-SD decrease in communication score was associated with 1.17 more retained complaints per 100 physicians per year (relative risk [RR], 1.38; 95% confidence interval [CI], 1.18-1.61) and 1.20 more communication complaints per 100 practice-years (RR, 1.43; 95% CI, 1.15-1.77). After adjusting for the predictive ability of the clinical decision-making score in the traditional written examination, the patient-physician communication score in the clinical skills examination remained significantly predictive of retained complaints (likelihood ratio test, P < .001), with scores in the bottom quartile explaining an additional 9.2% (95% CI, 4.7%-13.1%) of complaints., Conclusion: Scores achieved in patient-physician communication and clinical decision making on a national licensing examination predicted complaints to medical regulatory authorities.

Background: Individualized measures allow for the assessment of health-related quality of life (HRQL) based on areas that are relevant to the person and may prove to be useful for evaluating response shift (reconceptualization of HRQL and change in values)., Objective: The objective of this study was to assess reconceptualization of HRQL and change of individual values among persons with stroke during the first six months of recovery., Methods: The data collection for this study was incorporated into a randomized trial of acute post-stroke care. Individualized HRQL was evaluated at 6 and 24 weeks post-stroke using the Patient Generated Index (PGI). At 24 weeks a semi-structured interview was administered to assess whether verbalizations given by subjects indicated that they had experienced a response shift., Results: Ninety two subjects (61%) had complete PGI information at the 6- and 24-week evaluations, and of these, 46 completed the semi-structured interview. Between the 6- and 24-week evaluations, the domains selected were: the same for 10 (11%) subjects, reduced for 27 (29%), expanded for 11 (12%), and completely different for 44 (48%) subjects. Twenty eight percent (n = 13) of subjects recovering from stroke experienced a response shift as evidenced by the semi-structured interviews., Conclusion: The PGI provides valuable information regarding changes in person's conceptualization of HRQL and values, but the feasibility of using an individualized measure during the first six months post-stroke is limited by the added complexity of completing and interpreting such a measure.

Objective: It is generally assumed that interventions used to treat urinary incontinence (UI) in young women could simply be applied to older competent and motivated women, but these assumptions have not been formally tested. The purpose of this study was to determine the feasibility of using physical therapies to treat UI in older women., Design: Twelve-week time series., Settings and Subjects: We recruited women older than 75 years with UI from an outpatient urology clinic and a waiting list for incontinence surgery., Methods: After a baseline evaluation, the women collected data on their incontinence symptoms and bladder habits for 3 weeks using the 72-hour voiding diary and the 24-hour pad test. They then received 6 physical therapy treatments consisting of a combination of bladder training and pelvic floor muscle training assisted with biofeedback for 6 weeks. This was followed by another 3-week period of data collection and a final evaluation., Results: Ten women participated in the study; 7 completed it. They were all comfortable with the treatment. They complied with the study demands in terms of attendance at treatment session (100%), data collection (96%), and completion of exercises at home (82%). The authors observed a decrease in the number of incontinent and urgency episodes., Conclusion: This preliminary study demonstrates that some women older than 75 years are good candidates to undertake physical therapies for UI and follow study demands. Random controlled studies that include this population will provide evidence regarding the effectiveness of these therapies.

Background: Although obesity is associated with important hemodynamic disturbances, there are few data on population-wide blood pressure (BP) distribution in children and adolescents in this era of endemic pediatric obesity., Methods and Results: We conducted a school-based survey of a representative sample of youth aged 9, 13, and 16 years in Quebec, Canada. Resting BP was measured with an oscillometric device in 3589 subjects (80% response). Additional measures included height, weight, and subscapular and triceps skinfold thickness, an age-appropriate questionnaire, and a fasting blood draw. Mean (SD) systolic/diastolic BP (SBP/DBP) levels in 9-, 13-, and 16-year-olds were 103 (9)/57 (6), 113 (12)/58 (7), and 124 (14)/61 (7) mm Hg in males and 103 (10)/57 (6), 111 (11)/60 (7), and 114 (11)/62 (7) mm Hg in females. The prevalence of high-normal or elevated SBP was 12%, 22%, and 30% among 9-, 13-, and 16-year-old males, respectively, and 14%, 19%, and 17% among same-aged females. The prevalence of high-normal or elevated DBP was <1%. In multiple linear regression analysis, body mass index was consistently associated with SBP and DBP in all age-gender groups., Conclusions: Mean SBP and the prevalence of high-normal and elevated SBP are elevated in children and adolescents. Public policy, public health programs, and clinical preventive measures are urgently needed to address the obesity epidemic and its hemodynamic consequences.

Background: Plasma fasting insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) are markers of IR, which, at least in part, mediates the relation of obesity to increased cardiovascular risk. Increased free fatty acids (FFAs) may be involved in the pathogenesis of IR. Our objectives were to describe the distributions of fasting plasma insulin, glucose, and FFAs and HOMA-IR in youth and to assess the relationship between FFAs and markers of IR., Methods: Fasting plasma insulin, glucose, and FFAs were measured in a representative sample of Quebec youth comprising 2244 individuals 9, 13, and 16 years of age., Results: In all age and sex groups, glucose exhibited remarkably tight distributions (median CV, 7.1%) in contrast to insulin, HOMA-IR, and FFAs (median CVs, 52%, 54% and 45%, respectively). For every percentile examined, 9-year-olds had lower insulin concentrations and HOMA-IR values than 13- and 16-year-olds. We observed strong correlations between insulin concentrations and HOMA-IR values, as well as close similarity in their rankings of individuals. The mean concentrations of glucose were higher in our population than in other Caucasian pediatric populations. No positive correlations were detected between FFAs and markers of IR., Conclusions: We report some of the first data on the distributions of fasting plasma insulin, HOMA-IR, and FFAs from a representative sample of youth. HOMA-IR does not appear more informative than fasting insulin as a marker of IR. Our findings on higher mean glucose concentrations in this population require confirmation in other representative samples of youth to assess whether the North American distribution of glucose concentrations is shifting positively.

Background: Although atherosclerosis begins in childhood, there are no recent Canadian data on cardiovascular risk factors in provincially or nationally representative samples of youth., Objective: To describe the design and methods of the 1999 Québec Child and Adolescent Health and Social Survey, which assessed the prevalence and distribution of risk factors in a representative sample of Québec youth., Methods: School-based, multistage, cluster sampling survey of youth aged nine, 13 and 16 years. Measures included height, weight, subscapular and tricipital skinfolds, blood pressure (measured with the Dinamap), a fasting blood draw for assessment of lipoproteins and glucose, an age-adapted youth questionnaire on lifestyles and a parent questionnaire., Results: One thousand two hundred sixty-seven, 1186 and 1160 subjects aged nine, 13 and 16 years, respectively, responded to the questionnaire and had height, weight, skinfold thickness and blood pressure measured (response proportions of 83%, 79% and 78% respectively); 783, 818 and 874 subjects of the same age agreed to the blood draw (response proportions of 52%, 55% and 59%, respectively). Comparisons of characteristics of participants and nonparticipants in the blood draw showed few differences. The mean relative difference between lipoprotein and glucose values obtained at the study laboratory and a reference method varied from -0.3% to 6.1%. Design effects for means and proportions varied from 1.0 to 1.8., Conclusion: Despite its complexity, this survey was able to achieve a high level of precision for multiple measures. It will provide the most complete data on cardiovascular risk factors ever collected among children and adolescents in Canada.

Context: Standards for licensure are designed to provide assurance to the public of a physician's competence to practice. However, there has been little assessment of the relationship between examination scores and subsequent practice performance., Objective: To determine if there is a sustained relationship between certification examination scores and practice performance and if licensing examinations taken at the end of medical school are predictive of future practice in primary care., Design, Setting, and Participants: A total of 912 family physicians, who passed the Québec family medicine certification examination (QLEX) between 1990 and 1993 and entered practice. Linked databases were used to assess physicians' practice performance for 3.4 million patients in the universal health care system in Québec, Canada. Patients were seen during the follow-up period for the first 4 years (1993 cohort of physicians) to 7 years (1990 cohort of physicians) of practice from July 1 of the certification examination to December 31, 1996., Main Outcome Measures: Mammography screening rate, continuity of care index, disease-specific and symptom-relief prescribing rate, contraindicated prescribing rate, and consultation rate., Results: Physicians achieving higher scores on both examinations had higher rates (rate increase per SD increase in score per 1000 persons per year) of mammography screening (beta for QLEX, 16.8 [95% confidence interval [CI], 8.7-24.9]; beta for Medical Council of Canada Qualifying Examination [MCCQE], 17.4 [95% CI, 10.6-24.1]) and consultation (beta for QLEX, 4.9 [95% CI, 2.1-7.8]; beta for MCCQE, 2.9 [95% CI, 0.4-5.4]). Higher subscores in diagnosis were predictive of higher rates in the difference between disease-specific and symptom-relief prescribing (beta for QLEX, 3.9 [95% CI, 0.9-7.0]; beta for MCCQE, 3.8 [95% CI, 0.3-7.3]). Higher scores of drug knowledge were predictive of a lower rate (relative risk per SD increase in score) of contraindicated prescribing for MCCQE (relative risk, 0.88; 95% CI, 0.77-1.00). Relationships between examination scores and practice performance were sustained through the first 4 to 7 years in practice., Conclusion: Scores achieved on certification examinations and licensure examinations taken at the end of medical school show a sustained relationship, over 4 to 7 years, with indices of preventive care and acute and chronic disease management in primary care practice.

Context: Rising costs of medications and inequities in access have sparked calls for drug policy reform in the United States and Canada. Control of drug expenditures by prescription cost-sharing for elderly persons and poor persons is a contentious issue because little is known about the health impact in these subgroups., Objectives: To determine (1) the impact of introducing prescription drug cost-sharing on use of essential and less essential drugs among elderly persons and welfare recipients and (2) rates of emergency department (ED) visits and serious adverse events associated with reductions in drug use before and after policy implementation., Design and Setting: Interrupted time-series analysis of data from 32 months before and 17 months after introduction of a prescription coinsurance and deductible cost-sharing policy in Quebec in 1996. Separate 10-month prepolicy control and postpolicy cohort studies were conducted to estimate the impact of the drug reform on adverse events., Participants: A random sample of 93 950 elderly persons and 55 333 adult welfare medication recipients., Main Outcome Measures: Mean daily number of essential and less essential drugs used per month, ED visits, and serious adverse events (hospitalization, nursing home admission, and mortality) before and after policy introduction., Results: After cost-sharing was introduced, use of essential drugs decreased by 9.12% (95% confidence interval [CI], 8.7%-9.6%) in elderly persons and by 14.42% (95% CI, 13.3%-15.6%) in welfare recipients; use of less essential drugs decreased by 15.14% (95% CI, 14.4%-15.9%) and 22.39% (95% CI, 20.9%-23.9%), respectively. The rate (per 10 000 person-months) of serious adverse events associated with reductions in use of essential drugs increased from 5.8 in the prepolicy control cohort to 12.6 in the postpolicy cohort in elderly persons (a net increase of 6.8 [95% CI, 5.6-8.0]) and from 14.7 to 27.6 in welfare recipients (a net increase of 12.9 [95% CI, 10.2-15.5]). Emergency department visit rates related to reductions in the use of essential drugs also increased by 14.2 (95% CI, 8.5-19.9) per 10 000 person-months in elderly persons (prepolicy control cohort, 32.9; postpolicy cohort, 47.1) and by 54.2 (95% CI, 33.5-74.8) among welfare recipients (prepolicy control cohort, 69.6; postpolicy cohort, 123.8). These increases were primarily due to an increase in the proportion of recipients who reduced their use of essential drugs. Reductions in the use of less essential drugs were not associated with an increase in risk of adverse events or ED visits., Conclusions: In our study, increased cost-sharing for prescription drugs in elderly persons and welfare recipients was followed by reductions in use of essential drugs and a higher rate of serious adverse events and ED visits associated with these reductions.

Objective: To assess the coding accuracy of primary and secondary discharge diagnoses in the Quebec hospital discharge database for elderly persons with myocardial infarction (MI)., Design: Retrospective chart review in a convenience sample of six Montreal hospitals. The diagnoses listed in the medical chart were compared with those listed in the hospital discharge database. For each subject, the Charlson comorbidity index was calculated twice, once based on the medical chart and again based on the hospital discharge database., Patients: Subjects aged 65 years and over who had an MI coded as the primary discharge diagnosis in the hospital discharge database and who were discharged alive., Main Results: For 234 MI survivors, the positive predictive value (ie, probability that a patient with MI reported in the hospital discharge database had an MI diagnosed by the discharging physician) for coding MI was 0.96 (95% CI 0.94, 0.98). Comorbid medical conditions and complications of the MI were under-reported in the hospital discharge database, which meant that the Charlson index based on the hospital discharge database was an average of 0.71 units lower than the Charlson index based on the medical chart., Conclusions: When studying survivors of MI by using hospital discharge databases, the advantages must be weighed against potential drawbacks in the quality of the information. Hospital discharge databases are almost as reliable as medical charts for identifying MI patients, but there is substantial under-reporting of comorbid medical conditions.

The standard approach to government-mandated aerometric monitoring of airborne particulates across North America is to sample every sixth day year round. However, such data are inadequate for epidemiological studies which aim to examine daily time series relationships of particulate air pollution to respiratory health responses. The aim of the present study was to estimate missing daily particulate matter < or = 2.5 and < or = 10 microns in aerometric diameter (PM2.5 and PM10) and sulfate (SO4(2-) to a degree sufficiently accurate and reliable to allow the use of these estimates, along with the measured data, in an investigation of the relationship of air pollution to respiratory hospital admissions in Montreal during the 1980s. Prediction equations were developed for May through October periods using available daily levels of predictor variables which included: relative humidity-corrected light extinction coefficient (bext) derived from airport visual range sightings, coefficient of haze (COH), SO2, NOx, CO, O3, wind speed, wind direction, barometric pressure (BP), temperature, relative humidity, and total precipitation. Three fourths of the available gravimetric particulate data were used to develop prediction models, while the remaining fourth was used to test the reliability of the model (holdout data). All final models explained over 70% of the variability in the particulate air pollutants and were reliable when tested against the holdout data. The strongest (P < 0.001) and most consistent predictors were bext, COH, and O3 measured on the same day as the particulate, and BP lagged 1 day in the past. Other selected variables were same day NOx, BP, and minimum temperature. Although the present approach to the estimation of missing particulate air pollution may increase the level of exposure misclassification, it does allow for the use of existing network databases in epidemiological studies of daily air pollution health effects even though particulate data is only measured on certain days.

The relationship between the number of daily urgent hospital admissions for respiratory illnesses (31 hospitals) and ambient air pollution in Montreal, Canada, was investigated for warm periods between 1984 and 1988. Air pollutants included 1-hr and 8-hr maximum ozone, estimated particulate matter < or = 10 microns in aerometric diameter (PM10), and estimated sulfate (SO4(2-) fraction of PM10. Regression analyses controlled for seasonal and day-of-week trends, autocorrelation, temperature, and relative humidity. For July and August periods, there was a statistically significant (P < 0.01) univariate relationship of all respiratory admissions to 8-hr maximum ozone, which became nonsignificant when coregressed with temperature. Levels of ozone which never exceeded the U.S. National Ambient Air Quality Standard (NAAQS) of 120 ppb and high intercorrelations between ozone, particulates, and temperature may explain this finding. Asthma admissions in the May-October periods increased by 2.7% over mean levels for each 12 micrograms/m3 increase in PM10 levels 3 days prior to the admission day (95% confidence interval, 0.7 to 4.8%). In the July and August periods, hospital admissions for respiratory illnesses excluding asthma were 9.6% higher (95% confidence interval, 0.5 to 18.7%) when estimated SO4(2-) had exceeded 8.1 micrograms/m3 4 days prior to the admission day compared to days when SO4(2-) was at or below this level. There were no significant (P < 0.05) associations of a reference group of nonrespiratory admissions to air pollution after controlling for weather. The above results were found despite levels of PM10 which never exceeded the NAAQS of 150 micrograms/m3. The associations found are relevant to public health, since hospital admissions are expected to be accompanied by considerably more frequent occurrences of less serious outcomes. The present findings suggest that particulate air pollution during photochemically active periods is related to respiratory morbidity in Montreal.

The use of hospital databases for research into the respiratory effects of air pollution has been questioned. In an attempt to address that issue, reabstracts of 1,279 discharge records from 14 Montreal hospitals were compared with the universal health insurance database of Quebec. Agreement levels on discharge diagnoses were 94.9% for asthma; 75.5% for all other respiratory diagnoses combined, including upper airway infections, pneumonia, and coronary obstructive pulmonary disease (COPD) (90% after ignoring disagreements between closely related respiratory diagnoses); and 93.1% for a nonrespiratory comparison group. Factors associated with misclassification included use of nonurgent admissions; delays in hospital admission from emergency rooms; and differences in levels of diagnostic agreement between hospitals, age groups, and outcome groups. These should be taken into account in air pollution epidemiologic research in which databases of the kind commonly maintained in North American health care systems are used.

Most elderly persons with dementia are cared for at home, usually by the spouse or an adult child. The objective of the present study was to determine whether there is an excess of psychological and physical health problems among family caregivers (CGs) of elderly persons with dementia. Data were obtained by interview from close family members of dementia patients (CGs), and from a comparison group made up of close family members of patients undergoing cataract surgery (non-caregivers, NCGs). CGs had significantly higher levels of depression and physical symptoms than NCGs. The association between caregiving and the health variables was stronger among subjects who were the patient's spouse than among those who were the patient's child. Furthermore, greater behavioral disturbance in the demented patient was associated with higher levels of morbidity in the CG. The results suggest that CGs might benefit from careful monitoring of their health status, and from greater access to specialized support services.