Introduction

Covid-19 increases the risk of venous thromboembolism (VTE). 

Aim

To assess sex differences in temporal VTE risk and short-term mortality after Covid-19.

Methods

Retrospective population-level cohort in Alberta, Canada (2021 population 4,262,635) using administrative data. Covid-19 cases were SARS-CoV-2 polymerase chain reaction (PCR) positive (+) between 04-1-2020 and 12-15-2021. Each case was matched to 2 controls for age, sex, and rural vs urban residence. Controls were PCR negative (-) prior to and during the observation period. The primary outcome was first VTE event, defined using ICD-10 CA codes and ?1 imaging code. We used risk ratios at 1, 3, and 6 months and multivariable logistic regression to determine factors associated with 28-day mortality.

Results

There were 255,037 people with a PCR+ test and 509,876 controls. There were 921 VTE in Covid-19 patients and 954 VTE in controls (0.4% vs 0.2%, p<0.01). VTE risk post-Covid-19 was higher for males vs females (Figure) at 1, 3, and 6 months (p-interaction <0.001 at all points). Among PCR+ cases, VTE (adjusted odds ratio [aOR] 9.35, 95%CI 6.88-12.70) and males (aOR 1.98, 95%CI 1.87-2.15) had higher mortality, adjusting for age, rural residence and anticoagulant use.

Conclusions

Males have greater risks of VTE than females up to 6 months after Covid-19 infection and higher short-term risk of mortality at the population level.