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Randomized clinical trials provide reassurances that confounding factors are balanced at baseline whereas blinding is essential to assure the balance of extraneous factors thereafter. This article provides a three-part taxonomy of pitfalls that can arise because of inadequate blinding in clinical trials. We introduce a cautionary framework for readers interpreting a blinded randomized trial for evidence-based medicine. Each pitfall is illustrated with a relevant example of a potential bias resulting from knowledge of group assignment. Several pitfalls occur during the conduct of the study including inadequate blinding of the intervention group, control group, or responsible clinicians. Additional pitfalls relate to data analysis including unsubstantiated assertions of blinding and subverted tests for blinding. Further pitfalls arise due to surrounding oversight including unblinding of research ethics boards and scientific reviewers. These caveats are sources of misunderstanding when observing the apparent connection between a clinical intervention and patient outcomes. An awareness of specific pitfalls might help advance the interpretation and application of blinded randomized clinical trials to inform evidence-based medical care.
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BACKGROUND: Periprosthetic joint infection (PJI) remains a dreaded and unpredictable complication after total hip arthroplasty (THA). In addition to causing substantial morbidity, PJI may contribute to long-term mortality risk. Our objective was to determine the long-term mortality risk associated with PJI following THA. METHODS: This population-based, retrospective cohort study included adult patients (≥18 years old) in Ontario, Canada, who underwent their first primary elective THA for arthritis between April 1, 2002, and March 31, 2021. The primary outcome was death within 10 years after the index THA. Mortality was compared between propensity-score-matched groups (PJI within 1 year after surgery versus no PJI within 1 year after surgery) with use of survival analyses. Patients who died within 1 year after surgery were excluded to avoid immortal time bias. RESULTS: A total of 175,432 patients (95,883 [54.7%] women) with a mean age (and standard deviation) of 67 ± 11.4 years underwent primary THA during the study period. Of these, 868 patients (0.49%) underwent surgery for a PJI of the replaced joint within 1 year after the index procedure. After matching, patients with a PJI within the first year had a significantly higher 10-year mortality rate than their counterparts (11.4% [94 of 827 patients] versus 2.2% [18 of 827 patients]; absolute risk difference, 9.19% [95% confidence interval (CI), 6.81% to 11.6%]; hazard ratio, 5.49 [95% CI, 3.32 to 9.09]). CONCLUSIONS: PJI within 1 year after surgery is associated with over a fivefold increased risk of mortality within 10 years. The findings of this study underscore the importance of prioritizing efforts related to the prevention, diagnosis, and treatment of PJIs. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
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Background: Spinal metastases are a significant complication of advanced cancer. In this study, we assess temporal trends in the incidence and timing of spinal metastases and examine underlying patient demographics and primary cancer associations. Methods: In this population-based retrospective cohort study, health data from 2007 to 2019 in Ontario, Canada were analyzed (nâ =â 37, 375 patients identified with spine metastases). Primary outcomes were annual incidence of spinal metastasis, and time to metastasis after primary diagnosis. Results: The age-standardized incidence of spinal metastases increased from 229 to 302 cases per million over the 13-year study period. The average annual percent change (AAPC) in incidence was 2.2% (95% CI: 1.4% to 3.0%) with patients aged ≥85 years demonstrating the largest increase (AAPC 5.2%; 95% CI: 2.3% to 8.3%). Lung cancer had the greatest annual incidence, while prostate cancer had the greatest increase in annual incidence (AAPC 6.5; 95% CI: 4.1% to 9.0%). Lung cancer patients were found to have the highest risk of spine metastasis with 10.3% (95% CI: 10.1% to 10.5%) of patients being diagnosed at 10 years. Gastrointestinal cancer patients were found to have the lowest risk of spine metastasis with 1.0% (95% CI: 0.9% to 1.0%) of patients being diagnosed at 10 years. Conclusions: The incidence of spinal metastases has increased in recent years, particularly among older patients. The incidence and timing vary substantially among different primary cancer types. These findings contribute to the understanding of disease trends and emphasize a growing population of patients who require subspecialty care.
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This Viewpoint examines the potential problems of clinician reliance on the use of artificial intelligence (AI) in health care and offers suggestions on how AI could be designed to promote clinician vigilance.
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This case-control study describes the incidence of fatal traffic crashes in the US during the 2017 total solar eclipse.
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Acidentes de Trânsito , Humanos , Estados Unidos/epidemiologia , Acidentes de Trânsito/prevenção & controle , Luz Solar/efeitos adversos , MasculinoRESUMO
OBJECTIVE: Responsible media reporting is an accepted strategy for preventing suicide. In 2015, suicide prevention experts launched a media engagement initiative aimed at improving suicide-related reporting in Canada; its impact on media reporting quality and suicide deaths is unknown. METHOD: This pre-post observational study examined changes in reporting characteristics in a random sample of suicide-related articles from major publications in the Greater Toronto Area (GTA) media market. Articles (n = 900) included 450 from the 6-year periods prior to and after the initiative began. We also examined changes in suicide counts in the GTA between these epochs. We used chi-square tests to analyse changes in reporting characteristics and time-series analyses to identify changes in suicide counts. Secondary outcomes focused on guidelines developed by media professionals in Canada and how they may have influenced media reporting quality as well as on the overarching narrative of media articles during the most recent years of available data. RESULTS: Across-the-board improvement was observed in suicide-related reporting with substantial reductions in many elements of putatively harmful content and substantial increases in all aspects of putatively protective content. However, overarching article narratives remained potentially harmful with 55.2% of articles telling the story of someone's death and 20.8% presenting an other negative message. Only 3.6% of articles told a story of survival. After controlling for potential confounders, a nonsignificant numeric decrease in suicide counts was identified after initiative implementation (ω = -5.41, SE = 3.43, t = 1.58, p = 0.12). CONCLUSIONS: We found evidence that a strategy to engage media in Canada changed the content of reporting, but there was only a nonsignificant trend towards fewer suicides. A more fundamental change in media narratives to focus on survival rather than death appears warranted.
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Suicídio , Humanos , Canadá , Projetos de Pesquisa , Prevenção do SuicídioRESUMO
BACKGROUND: COVID vaccine hesitancy identifies a discrepancy between personal decisions and public guidelines. We tested whether COVID vaccine hesitancy was associated with the long-term risks of a traffic crash. METHODS: We conducted a population-based longitudinal cohort analysis of adults by determining COVID vaccination status through linkages to electronic medical records. Traffic crashes requiring emergency medical care were defined by multicenter outcome ascertainment of all hospitals throughout the region over the subsequent year. RESULTS: We identified 11,598,549 total individuals, of whom 1,210,754 had not received a COVID vaccine. A total of 54,558 were subsequently injured in traffic crashes during the 1-year follow-up interval, equal to a risk of 4704 per million. Those who had not received a COVID vaccine had a 58% higher risk than those who had received a COVID vaccine (6983 vs 4438 per million, P < .001). The increased traffic risks among unvaccinated individuals included diverse subgroups, were accentuated for single-vehicle crashes, extended to fatal outcomes, exceeded the risks associated with sleep apnea, and persisted after adjustment for baseline characteristics. The increased risks were validated in analyses using Artificial Intelligence techniques and generally larger than the risks of other adverse events frequently ascribed to COVID vaccination. CONCLUSIONS: COVID vaccine hesitancy is associated with significant increased long-term risks of a traffic crash. A greater awareness of traffic risks might encourage patients to take protective actions for personal safety.
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Vacinas contra COVID-19 , COVID-19 , Adulto , Humanos , Vacinas contra COVID-19/efeitos adversos , Inteligência Artificial , Hesitação Vacinal , COVID-19/epidemiologia , COVID-19/prevenção & controle , Acidentes de Trânsito , VacinaçãoRESUMO
STUDY OBJECTIVE: Syncope that occurs while driving can result in a motor vehicle crash. Whether individuals with a prior syncope-related crash exhibit an exceptional risk of subsequent crash remains uncertain. METHODS: We performed a population-based retrospective observational study of patients diagnosed with 'syncope and collapse' at any of 6 emergency departments in British Columbia, Canada (2010 to 2015). Data were obtained from chart abstraction, administrative health records, insurance claims and police crash reports. We compared crash-free survival among individuals with crash-associated syncope (a crash and an emergency visit for syncope on the same date) to that among controls with syncope alone (no crash on date of emergency visit for syncope). RESULTS: In the year following their index emergency visit, 13 of 63 drivers with crash-associated syncope and 852 of 9,160 controls with syncope alone experienced a subsequent crash as a driver (crash risk 21% versus 9%). After accounting for censoring and potential confounders, crash-associated syncope was not associated with a significant increase in the risk of subsequent crash (adjusted hazard ratio [aHR] 1.38, 95% confidence interval [CI] 0.78 to 2.47). Individuals with crash-associated syncope were 31-fold more likely to have physician driving advice documented during their index visit (prevalence ratio 31.0, 95% CI, 21.3 to 45.1). In the subgroup without documented driving advice, crash-associated syncope was associated with a significant increase in subsequent crash risk (aHR 1.88, 95% CI 1.06 to 3.36). CONCLUSIONS: Crash risk after crash-associated syncope appears similar to crash risk after syncope alone.
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Condução de Veículo , Humanos , Acidentes de Trânsito , Colúmbia Britânica/epidemiologia , Veículos Automotores , Síncope/epidemiologia , Síncope/etiologiaRESUMO
BACKGROUND: Among individuals with recent syncope, recurrence of syncope while driving might incapacitate a driver and cause a motor vehicle crash. Current driving restrictions assume that some forms of syncope transiently increase crash risk. We evaluated whether syncope is associated with a transient increase in crash risk. METHODS: We performed a case-crossover analysis of linked administrative health and driving data from British Columbia, Canada (2010 to 2015). We included licensed drivers who visited an emergency department with "syncope and collapse" and who were involved as a driver in an eligible motor vehicle crash, both within the study interval. Using conditional logistic regression, we compared the rate of emergency visits for syncope in the 28 days before crash (the "pre-crash interval") with the rate of emergency visits for syncope in 3 self-matched 28-day control intervals (ending 6, 12, and 18 months before the crash). RESULTS: Among eligible crash-involved drivers, 47 of 3026 pre-crash intervals and 112 of 9078 control intervals had emergency visits for syncope, indicating syncope was not significantly associated with subsequent crash (1.6% vs 1.2%; adjusted odds ratio [OR], 1.27; 95% confidence interval [CI], 0.90-1.79; P = 0.18). There was no significant association between syncope and crash in subgroups at higher risk for adverse outcomes after syncope (eg, age > 65 years, cardiovascular disease, cardiac syncope). CONCLUSIONS: In the context of prevailing modifications of driving behaviour after syncope, an emergency department visit for syncope did not transiently increase the risk of subsequent traffic collision. Overall crash risks after syncope appear to be adequately addressed by current driving restrictions.
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Condução de Veículo , Doenças Cardiovasculares , Humanos , Idoso , Acidentes de Trânsito , Modelos Logísticos , Colúmbia Britânica/epidemiologia , Síncope/epidemiologia , Síncope/etiologiaRESUMO
BACKGROUND: Resident call schedules require careful planning and are vulnerable to unanticipated absences from unpredictable factors. We tested whether unplanned absences from resident call schedules were associated with the likelihood of subsequent academic recognition. METHODS: We examined unplanned absences from call shifts for internal medicine residents at the University of Toronto from 2014 to 2022 (8 years). We identified institutional awards granted at the end of the academic year as an indicator of academic recognition. We defined the resident-year as the unit-of-analysis that started in July and ended in June of the subsequent year. Secondary analyses examined the association between unplanned absences and the likelihood of academic recognition in later years. RESULTS: We identified 1668 resident-years of training in internal medicine. In total, 579 (35%) had an unplanned absence, and the remaining 1089 (65%) had no unplanned absence. Baseline characteristics were similar between the two groups of residents. In total, 301 awards were received for academic recognition. The likelihood of receiving an award at the end of the year was 31% lower for residents who had any unplanned absence compared with those who had no absence (adjusted odds ratio = 0.69, 95% confidence interval 0.51-0.93, p = 0.015). The likelihood of receiving an award was further decreased for residents with multiple unplanned absences compared with those with none (odds ratio 0.54, 95% confidence interval 0.33-0.83, p = 0.008). An absence during the first year of residency was not significantly associated with the likelihood of academic recognition in later years of training (odds ratio 0.62, 95% confidence interval 0.36-1.04, p = 0.081). CONCLUSIONS: The results of this analysis suggest unplanned absences from scheduled call shifts may be associated with a decreased likelihood of academic recognition for internal medicine residents. This association could reflect countless confounders or the prevailing culture of medicine.
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Internato e Residência , Humanos , Estudos Retrospectivos , Estudos de Coortes , Medicina Interna/educaçãoRESUMO
Observational research can be strengthened by examining potential dose-response relationships that correlate a clinical intervention with a patient outcome. Despite being a classic criterion for establishing causality, dose-response testing can be difficult to interpret in clinical medicine due to multiple diverse pitfalls. This review introduces a cautionary framework for investigators considering dose-response relationships in observational research to support evidence-based medicine. Each pitfall is illustrated with a specific example relevant when analyzing a dose-response relationship. Several pitfalls stem from faulty interpretation including confounding by indication and fallible range selection. Additional pitfalls relate to improper analysis including fitting a nonlinear model and misclassification error. Further pitfalls arise in special situations including subjective self-report and artifacts from survival bias. These caveats are common sources of misunderstanding in analyses that examine the link between varying exposures and the intensity of clinical outcomes. Awareness of specific pitfalls, we suggest, might help advance the conduct, application, and translation of dose-response relationships in observational research to inform evidence-based medical care.
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Causalidade , Humanos , ViésRESUMO
Importance: Police shootings can cause serious acute injury, and knowledge of subsequent health outcomes may inform interventions to improve care. Objective: To analyze long-term health care costs among survivors of police shootings compared with those surviving nonfirearm police enforcement injuries using a retrospective design. Design, Setting, and Participants: This population-based cohort analysis identified adults (age ≥16 years) who were injured by police and required emergency medical care between April 1, 2002, and March 31, 2022, in Ontario, Canada. Exposure: Police shootings compared with other mechanisms of injury involving police. Main Outcomes and Measures: Long-term health care costs determined using a validated costing algorithm. Secondary outcomes included short-term mortality, acute care treatments, and rates of subsequent disability. Results: Over the study, 13â¯545 adults were injured from police enforcement (mean [SD] age, 35 [12] years; 11â¯637 males [86%]). A total of 13â¯520 individuals survived acute injury, and 8755 had long-term financial data available (88 surviving firearm injury, 8667 surviving nonfirearm injury). Patients surviving firearm injury had 3 times greater health care costs per year (CAD$16â¯223 vs CAD$5412; mean increase, CAD$9967; 95% CI, 6697-13â¯237; US $11â¯982 vs US $3997; mean increase, US $7361; 95% CI, 4946-9776; P < .001). Greater costs after a firearm injury were not explained by baseline costs and primarily reflected increased psychiatric care. Other characteristics associated with increased long-term health care costs included prior mental illness and a substance use diagnosis. Conclusions and Relevance: In this longitudinal cohort study of long-term health care costs, patients surviving a police shooting had substantial health care costs compared with those injured from other forms of police enforcement. Costs primarily reflected psychiatric care and suggest the need to prioritize early recognition and prevention.
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Armas de Fogo , Ferimentos por Arma de Fogo , Adulto , Masculino , Humanos , Adolescente , Ontário/epidemiologia , Estudos Longitudinais , Polícia , Estudos Retrospectivos , Custos de Cuidados de SaúdeRESUMO
BACKGROUND: Mortality statistics about daily deaths might change on weekends due to delays in reporting, uneven staffing, a different mix of personnel, or decreased efficiency. We hypothesized that reported deaths for COVID-19 might increase on weekends compared to weekdays. METHODS: We collected data from the World Health Organization COVID-19 database. All deaths from March 7, 2020 to March 7, 2022 were included (two years). The primary analysis evaluated mean daily deaths on weekends compared to the preceding five workdays. Analyses were replicated in ten individual countries: United States, United Kingdom, France, Germany, Italy, Spain, Russia, India, Brazil, and Canada. RESULTS: The mean COVID-19 daily deaths was higher on weekends compared to weekdays (8,532 vs. 8,083 p < 0.001), equal to a 6% relative increase (95% confidence interval 3% to 8%). The highest absolute increase was in the United States (1,483 vs. 1,220 deaths, p < 0.001). The second highest absolute increase was in Brazil (1,061 vs. 823 deaths, p < 0.001). The increase in deaths on weekends remained significant during the earlier and later months of the pandemic, as well as during the greater and lesser weeks of the pandemic. CONCLUSIONS: The apparent increased COVID-19 deaths reported on weekends might potentially reflect patient care, confound community trends, and affect the public perception of risk.
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COVID-19 , Humanos , Brasil/epidemiologia , Canadá , Bases de Dados Factuais , FrançaRESUMO
Importance: Identifying and mitigating modifiable gaps in fracture preventive care for people with relapsing-remitting conditions such as eczema, asthma, and chronic obstructive pulmonary disease who are prescribed high cumulative oral corticosteroid doses may decrease fracture-associated morbidity and mortality. Objective: To estimate the association between different oral corticosteroid prescribing patterns and appropriate fracture preventive care, including treatment with fracture preventive care medications, among older adults with high cumulative oral corticosteroid exposure. Design, Setting, and Participants: This cohort study included 65â¯195 participants with UK electronic medical record data from the Clinical Practice Research Datalink (January 2, 1998, to January 31, 2020) and 28â¯674 participants with Ontario, Canada, health administrative data from ICES (April 1, 2002, to September 30, 2020). Participants were adults 66 years or older with eczema, asthma, or chronic obstructive pulmonary disease receiving prescriptions for oral corticosteroids with cumulative prednisolone equivalent doses of 450 mg or higher within 6 months. Data were analyzed October 22, 2020, to September 6, 2022. Exposures: Participants with prescriptions crossing the 450-mg cumulative oral corticosteroid threshold in less than 90 days were classified as having high-intensity prescriptions, and participants crossing the threshold in 90 days or more as having low-intensity prescriptions. Multiple alternative exposure definitions were used in sensitivity analyses. Main Outcomes and Measures: The primary outcome was prescribed fracture preventive care. A secondary outcome was major osteoporotic fracture. Individuals were followed up from the date they crossed the cumulative oral corticosteroid threshold until their outcome or the end of follow-up (up to 1 year after index date). Rates were calculated for fracture preventive care and fractures, and hazard ratios (HRs) were estimated from Cox proportional hazards regression models comparing high- vs low-intensity oral corticosteroid prescriptions. Results: In both the UK cohort of 65â¯195 participants (mean [IQR] age, 75 [71-81] years; 32â¯981 [50.6%] male) and the Ontario cohort of 28â¯674 participants (mean [IQR] age, 73 [69-79] years; 17â¯071 [59.5%] male), individuals with high-intensity oral corticosteroid prescriptions had substantially higher rates of fracture preventive care than individuals with low-intensity prescriptions (UK: 134 vs 57 per 1000 person-years; crude HR, 2.34; 95% CI, 2.19-2.51, and Ontario: 73 vs 48 per 1000 person-years; crude HR, 1.49; 95% CI, 1.29-1.72). People with high- and low-intensity oral corticosteroid prescriptions had similar rates of major osteoporotic fractures (UK: crude rates, 14 vs 13 per 1000 person-years; crude HR, 1.07; 95% CI, 0.98-1.15 and Ontario: crude rates, 20 vs 23 per 1000 person-years; crude HR, 0.87; 95% CI, 0.79-0.96). Results from sensitivity analyses suggested that reaching a high cumulative oral corticosteroid dose within a shorter time, with fewer prescriptions, or with fewer or shorter gaps between prescriptions, increased fracture preventive care prescribing. Conclusions: The results of this cohort study suggest that older adults prescribed high cumulative oral corticosteroids across multiple prescriptions, or with many or long gaps between prescriptions, may be missing opportunities for fracture preventive care.