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Durbin A.,University of Toronto | Durbin A.,Institute for Clinical Evaluative science in Ontario | Lin E.,Institute for Clinical Evaluative science in Ontario | Lin E.,Health Services and Health Equity Research | And 4 more authors.
Canadian Journal of Psychiatry | Year: 2011

Objective: The immigrant population in Canada, and particularly in Ontario, is increasing. Our ecological study first assessed if there was an association between areas with proportions of first-generation immigrations and admissions rates for psychotic and affective disorders. Second, this study examined if area-level risks would persist after controlling for area socioeconomic factors in census-derived geographical areas - Forward Sortation Areas (FSAs) - in Ontario. Methods: Ontario's inpatient admission records from 1996 to 2005 and census data from 2001 were analyzed to derive FSA rates of first admissions for psychotic disorders and affective disorders per 100 000 person-years. Negative binomial regression models were adjusted, first, for FSA age and sex and, second, also for FSA population density and average income. Results: Using age- and sex-adjusted models, admission rates for psychotic disorders were higher in areas with greater proportions of immigrants. These areas were associated with lower admission rates for affective disorders. When FSA average income and population density were added to the models, the influence of immigrants was attenuated to nonsignificant levels in models predicting psychotic disorders admission rates. However, greater proportions of immigrants remained significantly protective when predicting rates of affective disorders. Discussion: Our study provides insight about the influence of area-level variables on risk of admission for psychotic and affective disorders in high immigrant areas. There is a dearth of current Canadian research on immigrant admission for psychotic disorders at the individual or area level. Future area- and individual-level studies may better identify groups at risk and possible explanations.


Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Research Institute | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,Center for Leading Injury Prevention Practice Education and Research | And 2 more authors.
Journal of General Internal Medicine | Year: 2012

Fallible human judgment may lead clinicians to make mistakes when assessing whether a patient is improving following treatment. This article provides a narrative review of selected studies in psychology that describe errors that potentially apply when a physician assesses a patient's response to treatment. Comprehension may be distorted by subjective preconceptions (lack of double blinding). Recall may fail through memory lapses (unwanted forgetfulness) and tacit assumptions (automatic imputation). Evaluations may be further compromised due to the effects of random chance (regression to the mean). Expression may be swayed by unjustified overconfidence following conformist groupthink (group polarization). An awareness of these five pitfalls may help clinicians avoid some errors in medical care when determining whether a patient is improving. © Society of General Internal Medicine 2012.


Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Health science Center | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,Sunnybrook Research Institute | Dickinson V.M.,Institute for Clinical Evaluative science in Ontario
Journal of General Internal Medicine | Year: 2011

Human perception is fallible and may lead patients to be inaccurate when judging whether their symptoms are improving with treatment. This article provides a narrative review of studies in psychology that describe misconceptions related to a patient's comprehension, recall, evaluation and expression. The specific misconceptions include the power of suggestion (placebo effects), desire for peace-of-mind (cognitive dissonance reduction), inconsistent standards (loss aversion), a flawed sense of time (duration neglect), limited perception (measurement error), declining sensitivity (Weber's law), an eagerness to please (social desirability bias), and subtle affirmation (personal control). An awareness of specific pitfalls might help clinicians avoid some mistakes when providing follow-up and interpreting changes in patient symptoms. © 2011 Society of General Internal Medicine.


Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Research Institute | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,Sunnybrook Health science Center | And 7 more authors.
New England Journal of Medicine | Year: 2012

BACKGROUND: Physicians' warnings to patients who are potentially unfit to drive are a medical intervention intended to prevent trauma from motor vehicle crashes. We assessed the association between medical warnings and the risk of subsequent road crashes. METHODS: We identified consecutive patients who received a medical warning in Ontario, Canada, between April 1, 2006, and December 31, 2009, from a physician who judged them to be potentially unfit to drive. We excluded patients who were younger than 18 years of age, who were not residents of Ontario, or who lacked valid healthcard numbers under universal health insurance. We analyzed emergency department visits for road crashes during a baseline interval before the warning and a subsequent interval after the warning. RESULTS: A total of 100,075 patients received a medical warning from a total of 6098 physicians. During the 3-year baseline interval, there were 1430 road crashes in which the patient was a driver and presented to the emergency department, as compared with 273 road crashes during the 1-year subsequent interval, representing a reduction of approximately 45% in the annual rate of crashes per 1000 patients after the warning (4.76 vs. 2.73, P<0.001). The lower rate was observed across patients with diverse characteristics. No significant change was observed in subsequent crashes in which patients were pedestrians or passengers. Medical warnings were associated with an increase in subsequent emergency department visits for depression and a decrease in return visits to the responsible physician. CONCLUSIONS: Physicians' warnings to patients who are potentially unfit to drive may contribute to a decrease in subsequent trauma from road crashes, yet they may also exacerbate mood disorders and compromise the doctor-patient relationship. (Funded by the Canada Research Chairs program and others.) Copyright © 2012 Massachusetts Medical Society.


Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Health science Center | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,Sunnybrook Research Institute | And 3 more authors.
PLoS Medicine | Year: 2010

Teenage male drivers contribute to a large number of serious road crashes despite low rates of driving and excellent physical health. We examined the amount of road trauma involving teenage male youth that might be explained by prior disruptive behavior disorders (attention deficit hyperactivity disorder, conduct disorder, oppositional defiant disorder). We conducted a population-based case-control study of consecutive male youth between age 16 and 19 years hospitalized for road trauma (cases) or appendicitis (controls) in Ontario, Canada over 7 years (April 1, 2002 through March 31, 2009). Using universal health care databases, we identified prior psychiatric diagnoses for each individual during the decade before admission. Overall, a total of 3,421 patients were admitted for road trauma (cases) and 3,812 for appendicitis (controls). A history of disruptive behavior disorders was significantly more frequent among trauma patients than controls (767 of 3,421 versus 664 of 3,812), equal to a one-third increase in the relative risk of road trauma (odds ratio = 1.37, 95% confidence interval 1.22-1.54, p<0.001). The risk was evident over a range of settings and after adjustment for measured confounders (odds ratio 1.38, 95% confidence interval 1.21-1.56, p<0.001). The risk explained about one-in-20 crashes, was apparent years before the event, extended to those who died, and persisted among those involved as pedestrians. Conclusion: Disruptive behavior disorders explain a significant amount of road trauma in teenage male youth. Programs addressing such disorders should be considered to prevent injuries. © 2010 Redelmeier et al.


Moss J.H.,University of Toronto | Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Research Institute | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario
General Hospital Psychiatry | Year: 2010

Objective: Psychiatric inpatients may be detained against their will, yet they still retain the right to apply for a hearing to challenge this detention. We tested whether adjudicated decisions over whether to uphold or rescind the detention have implications in subsequent patient morbidity. Methods: Consecutive patients applying to the Consent and Capacity Board in Ontario between January 1, 2004, and March 31, 2007, were identified who had a hearing to challenge their involuntary detention. Population based databases provided information on subsequent deaths, hospitalization for a psychiatric illness, or emergency department visit for any reason. Results: A total of 3498 decisions were rendered for 2321 unique psychiatric patients during the 39 month study period. Almost all patients (90%) had a prior psychiatric admission. Approximately 18% of involuntary detentions were rescinded with subsequent outcomes showing a greater likelihood of emergency department visits within 100 days of discharge in the group whose detention was rescinded compared to the group whose detention was upheld (46% vs. 36%, P=.003). Conclusions: When an involuntary detention is rescinded patients have a high likelihood of subsequent utilization of emergency department services for suicide related symptoms but no large increase in risk of dying. © 2010 Elsevier Inc. All rights reserved.


Redelmeier D.A.,University of Toronto | Redelmeier D.A.,Sunnybrook Research Institute | Redelmeier D.A.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,Sunnybrook Health science Center | And 3 more authors.
Journal of General Internal Medicine | Year: 2013

The purpose of this review is to describe ten potential pitfalls for practicing clinicians who use smartphones during active patient care (Textbox). These devices are an integral element of modern medical care and will certainly endure for the years ahead; hence, a listing of latent caveats does not nullify their many advantages toward efficient medical care. An awareness of specific pitfalls might help clinicians harness more of the benefits and avoid some of the problems. This list may also help guide future engineering research that seeks to mitigate problems with current smartphones. The toughest problems to solve are the ones you don't know you have and the ones that your predecessors never encountered. © 2013 Society of General Internal Medicine.


Ackery A.D.,University of Toronto | McLellan B.A.,University of Toronto | McLellan B.A.,Sunnybrook Health science Center | Redelmeier D.A.,University of Toronto | And 3 more authors.
Injury Prevention | Year: 2012

Objectives Bicycling is a popular means of transportation that is sometimes associated with injury from collisions. The authors analysed national data for the USA to evaluate bicyclist deaths associated with motor vehicle impacts. Methods The authors conducted a population-based caseecontrol analysis of road deaths reported by the National Highway Traffic Safety Administration. The authors included bicyclist deaths from 1 January 2008 to 31 December 2008 (cases), along with the non-bicyclist road deaths immediately before and after the bicyclist death in the same state (controls). Analyses also included linkages to auto appraisal websites to estimate type, size and cost of the motor vehicle involved in each death. Results A total of 711 bicyclist deaths were included, equivalent to a rate of 2 deaths per million population annually. No state had a rate statistically significantly below the national average whereas Florida was a high outlier with three times the national rate (p<0.001). The typical bicyclist who died was a man travelling in the afternoon or evening. The average estimated resale value of the involved motor vehicle was about one-third higher for bicyclist deaths than control deaths (US$10 603 vs US$8118, p<0.001). Analyses based on median estimated resale value and luxury resale value yielded similar findings. Stratified analyses based on demographics, time and posted speed limits yielded similar discrepancies. Larger motor vehicles were particularly common in bicyclist deaths compared to control deaths, especially freight trucks (11% vs 8%, p=0.008) and large automobiles (43% vs 37%, p=0.004). Conversely, motorcycles were distinctly infrequent in bicyclist deaths compared to control deaths (1% vs 14%, p<0.001). Conclusions Large expensive motor vehicles account for a disproportionate share of bicyclist deaths. Bicyclists, motorists, policy-makers and vehicle manufacturers need to consider more imaginative solutions to help prevent future deaths.


Schlenker M.B.,University of Toronto | Thiruchelvam D.,Sunnybrook Research Institute | Thiruchelvam D.,Institute for Clinical Evaluative science in Ontario | Redelmeier D.A.,University of Toronto | And 3 more authors.
American Journal of Ophthalmology | Year: 2015

Purpose To evaluate the subsequent risk of thromboembolic events in patients receiving intravitreal ranibizumab and bevacizumab for age-related macular degeneration or macular edema. Design Population-based crossover analysis with self-matched historical control data. Methods setting: Ontario, Canada, between April 1, 2006, and March 31, 2013. study population: Consecutive patients 65 and older who initiated intravitreal treatment (N = 57 919). intervention: Intravitreal injection of ranibizumab or bevacizumab. main outcome measures: Emergency visits for thromboembolic events spanning 1-4 years before treatment were compared to 1 year after treatment. Also examined were other secondary events including hip fractures, congestive heart failure, angina, falls, depression, cholecystitis, and total emergencies, as well as a control group following cataract surgery. Results A total of 57 919 patients were included who accounted for 1858 thromboembolic emergencies (48 per month) during the 3-year Baseline interval and 1077 thromboembolic emergencies (83 per month) during the 1-year Subsequent interval after initiating treatment. The absolute change in risk equaled an increase from 10.7 to 18.6 per 1000 patients annually after initiation of treatment (rate ratio 1.74; 95% confidence interval 1.58-1.92; P <.0001). The relative increase was particularly pronounced for ischemic stroke (rate ratio 2.18; 95% confidence interval 1.94-2.46; P <.0001). The observed increase exceeded trends due to aging, applied across patients with diverse characteristics, occurred with each medication (ranibizumab and bevacizumab), was not apparent for emergencies unrelated to thromboembolic events, and did not occur in a control group following cataract surgery. Conclusions Intravitreal anti-vascular endothelial growth factor medications ranibizumab and bevacizumab may contribute to systemic thromboembolic events in patients aged 65 years or older. © 2015 Elsevier Inc. All rights reserved.


PubMed | University of Toronto, Institute for Clinical Evaluative science in Ontario and Sunnybrook Research Institute
Type: Journal Article | Journal: Journal of clinical epidemiology | Year: 2014

We developed a new research approach, called cross-linked survey analysis, to explore how an acute exposure might lead to changes in survey responses. The goal was to identify associations between exposures and outcomes while reducing some ambiguities related to interpreting cause and effect in survey responses from a population-based community questionnaire.Cross-linked survey analysis differs from a cross-sectional, longitudinal, and panel survey analysis by individualizing the timeline to the unique history of each respondent. Cross-linked survey analysis, unlike a repeated-measures self-matching design, does not track changes in a repeated survey question given to the same respondent at multiple time points.Pilot data from three analyses (n = 1,177 respondents) illustrate how a cross-linked survey analysis can control for population shifts, temporal trends, and reverse causality. Accompanying graphs provide an intuitive display to readers, summarize results, and show differences in response distributions. Population-based individual-level linkages also reduce selection bias and increase statistical power compared with a single-center cross-sectional survey. Cross-linked survey analysis has limitations related to unmeasured confounding, pragmatics, survivor bias, statistical models, and the underlying artifacts in survey responses.We suggest that a cross-linked survey analysis may help in epidemiology science using survey data.

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