No additional risk of VTE among COVID-19 patients with immune mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) categorized as a heterogeneous group of chronic diseases that result from abnormal activation of the immune system, affecting 5% to 7% of people in the Western world. COVID-19 is reported to cause widespread inflammation; hyperactivation of this systemic immune response may ultimately cause multiorgan failure and death.

A recent cohort study conducted using health administrative data from Ontario, Canada, the incidence of venous thromboembolism (VTE) was low among individuals with IMIDs. The findings of the study are published in JAMA Network.

Researchers conducted a population-based matched cohort study using multiple deterministically linked health administrative databases. Individuals with IMIDs (n = 28 440) who tested positive for COVID-19 were matched with up to 5 individuals without an IMID (n = 126 437) who tested positive for COVID-19. Diagnosis of an IMID, identified using algorithms based on diagnostic codes, procedures, and specialist visits. The main outcome was estimated age- and sex-standardized incidence of VTE. Proportional cause-specific hazard models compared the risk of VTE in people with and without IMIDs. Death was a competing risk. Models adjusted for history of VTE, 2 or more doses of a COVID-19 vaccine 14 or more days prior to COVID-19 diagnosis, and the Charlson Comorbidity Index. Routinely collected health data were used, so the hypothesis tested was formulated after data collection but prior to being granted access to data.

The key findings of the study are

• The study included 28 440 individuals (16 741 [58.9%] female; 11 699 [41.1%] male) with an IMID diagnosed prior to first COVID-19 diagnosis, with a mean (SD) age of 52.1 (18.8) years at COVID-19 diagnosis.

• These individuals were matched to 126 437 controls without IMIDs. The incidence of VTE within 6 months of COVID-19 diagnosis among 28 440 individuals with an IMID was 2.64 (95% CI, 2.23-3.10) per 100 000 person-days compared with 2.18 (95% CI, 1.99-2.38) per 100 000 person-days among 126 437 matched individuals without IMIDs.

• The VTE risk was not statistically significantly different among those with vs without IMIDs (adjusted hazard ratio, 1.12; 95% CI, 0.95-1.32).

Researchers concluded that “In this retrospective population-based cohort study of individuals with IMIDs following COVID-19, individuals with IMIDs did not have a higher risk of VTE compared with individuals without an IMID. These data provide reassurance to clinicians caring for individuals with IMIDs and COVID-19.”

Reference: Khan R, Kuenzig ME, Tang F, et al. Venous Thromboembolism After COVID-19 Infection Among People With and Without Immune-Mediated Inflammatory Diseases. JAMA Netw Open. 2023;6(10):e2337020. doi:10.1001/jamanetworkopen.2023.37020.