Association of COVID-19 Vaccination With Breakthrough Infections and Complications in Patients With Cancer.

Importance: Patients with cancer are known to have increased risk of COVID-19 complications, including death. Objective: To determine the association of COVID-19 vaccination with breakthrough infections and complications in patients with cancer compared to noncancer controls. Design, Setting, and Participants: Retrospective population-based cohort study using linked administrative databases in Ontario, Canada, in residents 18 years and older who received COVID-19 vaccination. Three matched groups were identified (based on age, sex, type of vaccine, date of vaccine): 1:4 match for patients with hematologic and solid cancer to noncancer controls (hematologic and solid cancers separately analyzed), 1:1 match between patients with hematologic and patients with solid cancer. Exposures: Cancer diagnosis. Main Outcomes and Measures: Outcomes occurring 14 days after receipt of second COVID-19 vaccination dose: primary outcome was SARS-CoV-2 breakthrough infection; secondary outcomes were emergency department visit, hospitalization, and death within 4 weeks of SARS-CoV-2 infection (end of follow-up March 31, 2022). Multivariable cumulative incidence function models were used to obtain adjusted hazard ratio (aHR) and 95% CIs. Results: A total of 289 400 vaccinated patients with cancer (39 880 hematologic; 249 520 solid) with 1 157 600 matched noncancer controls were identified; the cohort was 65.4% female, and mean (SD) age was 66 (14.0) years. SARS-CoV-2 breakthrough infection was higher in patients with hematologic cancer (aHR, 1.33; 95% CI, 1.20-1.46; P < .001) but not in patients with solid cancer (aHR, 1.00; 95% CI, 0.96-1.05; P = .87). COVID-19 severe outcomes (composite of hospitalization and death) were significantly higher in patients with cancer compared to patients without cancer (aHR, 1.52; 95% CI, 1.42-1.63; P < .001). Risk of severe outcomes was higher among patients with hematologic cancer (aHR, 2.51; 95% CI, 2.21-2.85; P < .001) than patients with solid cancer (aHR, 1.43; 95% CI, 1.24-1.64; P < .001). Patients receiving active treatment had a further heightened risk for COVID-19 severe outcomes, particularly those who received anti-CD20 therapy. Third vaccination dose was associated with lower infection and COVID-19 complications, except for patients receiving anti-CD20 therapy. Conclusions and Relevance: In this large population-based cohort study, patients with cancer had greater risk of SARS-CoV-2 infection and worse outcomes than patients without cancer, and the risk was highest for patients with hematologic cancer and any patients with cancer receiving active treatment. Triple vaccination was associated with lower risk of poor outcomes.

Factors associated with timely COVID-19 vaccination in a population-based cohort of patients with cancer.

BACKGROUND: In many jurisdictions, cancer patients were prioritized for COVID-19 vaccination because of increased risk of infection and death. To understand sociodemographic disparities that affected timely receipt of COVID-19 vaccination among cancer patients, we undertook a population-based study in Ontario, Canada. METHODS: Patients older than 18 years and diagnosed with cancer January 2010 to September 2020 were identified using administrative data; vaccination administration was captured between approval (December 2020) up to February 2022. Factors associated with time to vaccination were evaluated using multivariable Cox proportional hazards regression. RESULTS: The cohort consisted of 356 535 patients, the majority of whom had solid tumor cancers (85.9%) and were not on active treatment (74.1%); 86.8% had received at least 2 doses. The rate of vaccination was 25% lower in recent (hazard ratio [HR] = 0.74, 95% confidence interval [CI] = 0.72 to 0.76) and nonrecent immigrants (HR = 0.80, 95% CI = 0.79 to 0.81). A greater proportion of unvaccinated patients were from neighborhoods with a high concentration of new immigrants or self-reported members of racialized groups (26.0% vs 21.3%, standardized difference = 0.111, P < .001), residential instability (27.1% vs 23.0%, standardized difference = 0.094, P < .001), or material deprivation (22.1% vs 16.8%, standardized difference = 0.134, P < .001) and low socioeconomic status (20.9% vs 16.0%, standardized difference = 0.041, P < .001). The rate of vaccination was 20% lower in patients from neighborhoods with the lowest socioeconomic status (HR = 0.82, 95% CI = 0.81 to 0.84) and highest material deprivation (HR = 0.80, 95% CI = 0.78 to 0.81) relative to those in more advantaged neighborhoods. CONCLUSIONS: Despite funding of vaccines and prioritization of high-risk populations, marginalized patients were less likely to be vaccinated. Differences are likely due to the interplay between systemic barriers to access and cultural or social influences affecting uptake.

Changes over time in patient visits and continuity of care among graduating cohorts of family physicians in 4 Canadian provinces.

BACKGROUND: Lack of patient access to family physicians in Canada is a concern. The role of recent physician graduates in this problem of supply of primary care services has not been established. We sought to establish whether career stage or graduation cohort were related to family physician practice volume and continuity of care over time. METHODS: We conducted a retrospective cohort study of family physician practice from 1997/98 to 2017/18. We collected administrative health and physician claims data in British Columbia, Manitoba, Ontario and Nova Scotia. We included all physicians who registered with their respective provincial regulatory colleges as having a medical specialty of family practice or who had billed the provincial health insurance system for patient care as family physicians, or both. We used regression models to isolate the effects of 3-year categories of years in practice (at all career stages), time period and cohort on patient contacts and physician-level continuity of care. RESULTS: Between 1997/98 and 2017/18, the median number of patient contacts per provider per year fell by between 515 and 1736 contacts in the 4 provinces examined. Median contacts peaked at 27-29 years in practice in all provinces, and median physician-level continuity of care increased until 30 or more years in practice. We found no association between graduation cohort and patient contacts or physician-level continuity of care. INTERPRETATION: Recent cohorts of family physicians practise similarly to their predecessors in terms of practice volumes and continuity of care. Because family physicians of all career stages showed declining patient contacts, we suggest that system-wide solutions to recent challenges in the accessibility of primary care in Canada are needed.

Psychiatric disorders in adults with cerebral palsy.

BACKGROUND: Cerebral palsy (CP) is one of the most common neurological conditions in childhood. Individuals with CP often experience various secondary conditions, including intellectual disability (ID), medical conditions, and psychiatric issues. A large number of youth with CP have psychiatric disorders; however, few studies have examined the prevalence of psychiatric issues in adults with CP at the population-level. AIMS: To investigate the prevalence and co-occurrence of psychiatric disorders at the population-level in adults with CP only, and adults with CP and ID. METHOD AND PROCEDURES: Using clinical information from seven Canadian data sources, we conducted a retrospective cross-sectional analysis of adults with CP, with and without ID. OUTCOMES AND RESULTS: Adults with CP were more likely than the general population to have a psychiatric diagnosis, independent of ID status. All psychiatric disorders were more common in individuals with CP than the general population, with the exception of addiction related disorders. In most cases, having an ID substantially increased the risk of having a psychiatric disorder. CONCLUSIONS: Adults with CP are at heightened risk for experiencing psychiatric disorders. Current findings highlight the important role health care providers play in screening for psychiatric issues in individuals with CP.

Asthma and chronic obstructive pulmonary disease (COPD) prevalence and health services use in Ontario Métis: a population-based cohort study.

INTRODUCTION: Chronic respiratory diseases cause a significant health and economic burden around the world. In Canada, Aboriginal populations are at increased risk of asthma and chronic obstructive pulmonary disease (COPD). There is little known, however, about these diseases in the Canadian Métis population, who have mixed Aboriginal and European ancestry. A population-based study was conducted to quantify asthma and COPD prevalence and health services use in the Métis population of Ontario, Canada's largest province. METHODS: The Métis Nation of Ontario Citizenship Registry was linked to provincial health administrative databases to measure and compare burden of asthma and COPD between the Métis and non-Métis populations of Ontario between 2009 and 2012. Asthma and COPD prevalence, health services use (general physician and specialist visits, emergency department visits, hospitalizations), and mortality were measured. RESULTS: Prevalences of asthma and COPD were 30% and 70% higher, respectively, in the Métis compared to the general Ontario population (p<0.001). General physician and specialist visits were significantly lower in Métis with asthma, while general physician visits for COPD were significantly higher. Emergency department visits and hospitalizations were generally higher for Métis compared to non-Métis with either disease. All-cause mortality in Métis with COPD was 1.3 times higher compared to non-Métis with COPD (p = 0.01). CONCLUSION: There is a high burden of asthma and COPD in Ontario Métis, with significant prevalence and acute health services use related to these diseases. Lower rates of physician visits suggest barriers in access to primary care services.