Methods Projects

The risk of arterial thromboembolism and venous thromboembolism among patients diagnosed with COVID-19 varied by country. This variation was observed among patients initially diagnosed in the ambulatory setting and the hospital setting, and before and during COVID-19 vaccine availability. Differences in healthcare systems, data sources, prevalence of underlying comorbid conditions, and approaches to COVID-19 and thromboembolism case definition may have contributed to the variation in thromboembolism risk estimates observed between countries.

In September 2019, Health Canada directed domestic manufacturers to cease distributing ranitidine due to potentially high concentrations of the possible carcinogen N-nitrosodimethylamine (NDMA). This study will characterize the use of dispensed histamine-2 receptor antagonists (H2RAs) in Canada by describing demographic and clinical characteristics of users and prescribers.

This multi-province validation study supports the use of inpatient and ED records as alternatives to population- based laboratory tests for identification of COVID-19 cases during the first year of the pandemic.
Our findings do not support the use of outpatient service claims to identify people infected with COVID-19.

The use of hydrochlorothiazide (HCTZ) was not associated with increased overall risks of keratinocyte carcinoma or melanoma when compared with angiotensin-converting enzyme inhibitors (ACEIs). However, elevated risks of keratinocyte carcinoma and melanoma were observed with longer durations of use (≥10 years) and higher cumulative doses (≥100,000 mg) of HCTZ, particularly when compared with calcium channel blockers (CCBs).

In Canada, an immediate steep decline in valsartan use was observed after the July 2018 recall accompanied by increased switching to other angiotensin receptor blocker (ARB) products. Subsequent recalls for losartan and irbesartan were also associated with increased switching, but overall trends in use remained unchanged. Despite availability of uncontaminated ARB products at the time of the recall, findings show that the immediate response was to switch patients to another ARB.

In this large study of 4,103,695 pregnancies, ondansetron use during pregnancy was not associated with increased risks of fetal death, spontaneous abortion, stillbirth, or major congenital malformation, when compared with other commonly used antiemetic drugs.