Background incidence rates of hospitalisations and emergency department visits for thromboembolic and coagulation disorders in Ontario, Canada for COVID-19 vaccine safety assessment: a population-based retrospective observational study.

Objective: The objective of this study was to estimate background rates of selected thromboembolic and coagulation disorders in Ontario, Canada.

Design: Population-based retrospective observational study using linked health administrative databases. Records of hospitalisations and emergency department visits were searched to identify cases using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada diagnostic codes.

Prescription medications dispensed following a nontraumatic spinal cord dysfunction: a retrospective population-based study in Ontario, Canada.

Study Design: Retrospective cohort study.

Objectives: To examine the prevalence of polypharmacy for individuals with nontraumatic spinal cord dysfunction (NTSCD) following inpatient rehabilitation and to determine associated risk factors.

Setting: Ontario, Canada.

Association of Low-Value Testing With Subsequent Health Care Use and Clinical Outcomes Among Low-risk Primary Care Outpatients Undergoing an Annual Health Examination.

Importance: The association of low-value testing with downstream care and clinical outcomes among primary care outpatients is unknown to date.

Objective: To assess the association of low-value testing with subsequent care among low-risk primary care outpatients undergoing an annual health examination (AHE).

Design, Setting, And Participants: This population-based retrospective cohort study used administrative health care claims from Ontario, Canada, for primary care outpatients undergoing an AHE between April 1, 2012, and March 31, 2016, to identify individuals who could be placed into one (or more) of the following 3 cohorts: adult patients (18 years or older) at low risk for cardiovascular and pulmonary disease, adult patients at low risk for cardiovascular disease, and female patients (aged 13-20 years or older than 69 years) at low risk for cervical cancer.

Effectiveness of inactivated influenza vaccines in preventing influenza-associated deaths and hospitalizations among Ontario residents aged ≥ 65 years: estimates with generalized linear models accounting for healthy vaccinee effects.

Background: Estimates of the effectiveness of influenza vaccines in older adults may be biased because of difficulties identifying and adjusting for confounders of the vaccine-outcome association. We estimated vaccine effectiveness for prevention of serious influenza complications among older persons by using methods to account for underlying differences in risk for these complications.

Methods: We conducted a retrospective cohort study among Ontario residents aged ≥ 65 years from September 1993 through September 2008.

Low rates of influenza immunization in young children under Ontario's universal influenza immunization program.

Objectives: To determine physician-administered influenza vaccine coverage for children aged 6 to 23 months in a jurisdiction with a universal influenza immunization program during 2002-2009 and to describe predictors of vaccination.

Methods: By using hospital records, we identified all infants born alive in Ontario hospitals from April 2002 through March 2008. Immunization status was ascertained by linkage to physician billing data.

Sex differences in implantable cardioverter-defibrillator outcomes: findings from a prospective defibrillator database.

Background: Sex differences in the use and outcomes of implantable cardioverter-defibrillators (ICDs) have not been fully studied.

Objective: To examine potential sex differences in ICD implantation and device outcomes.

Design: Health payer-mandated, prospective study of patients referred for ICD implantation, with comprehensive, longitudinal follow-up for complications, deaths, and device outcomes.