Thromboembolic Risk in Hospitalized and Nonhospitalized COVID-19 Patients: A Self-Controlled Case Series Analysis of a Nationwide Cohort

Frederick K Ho,Kenneth K.C Man,Mark Toshner,Colin Church,Carlos Celis-Morales,Ian C.K Wong,Colin Berry,Naveed Sattar,Jill P Pell

doi:10.1016/j.mayocp.2021.07.002

Abstract

ObjectiveTo assess the associations between coronavirus disease 2019 (COVID-19) infection and thromboembolism including myocardial infarction (MI), ischemic stroke, deep vein thrombosis (DVT), and pulmonary embolism (PE). Patients and MethodsA self-controlled case-series study was conducted covering the whole of Scotland’s general population. The study population comprised individuals with confirmed (positive test) COVID-19 and at least one thromboembolic event between March 2018 and October 2020. Their incidence rates during the risk interval (5 days before to 56 days after the positive test) and the control interval (the remaining periods) were compared intrapersonally. ResultsAcross Scotland, 1449 individuals tested positive for COVID-19 and experienced a thromboembolic event. The risk of thromboembolism was significantly elevated over the whole risk period but highest in the 7 days following the positive test (incidence rate ratio, 12.01; 95% CI, 9.91 to 14.56) in all included individuals. The association was also present in individuals not originally hospitalized for COVID-19 (incidence rate ratio, 4.07; 95% CI, 2.83 to 5.85). Risk of MI, stroke, PE, and DVT were all significantly higher in the week following a positive test. The risk of PE and DVT was particularly high and remained significantly elevated even 56 days following the test. ConclusionConfirmed COVID-19 infection was associated with early elevations in risk with MI, ischemic stroke, and substantially stronger and prolonged elevations with DVT and PE both in hospital and community settings. Clinicians should consider thromboembolism, especially PE, among people with COVID-19 in the community.

Highlights

Compared with people aged older than 75 years, those younger had 23 and 47 times higher elevated thromboembolism and pulmonary embolism (PE) risk, respectively, within 7 days of a positive COVID-19 test (Table 3)
The median age was older for ischemic stroke (82 years) and younger for pulmonary embolism (PE) (71 years) and deep vein thrombosis (DVT) (73 years)
Individuals who had a COVID-19 infection were at a higher risk of all of the outcomes, with strongest association with PE, followed by DVT (HR, 10.45; 95% CI, 7.02 to 15.56), ischemic stroke (HR, 4.40; 95% CI, 3.44 to 5.63), and myocardial infarction (MI) (HR, 3.31; 95% CI, 2.59 to 4.22)

Summary

Introduction

Compared with people aged older than 75 years, those younger had 23 and 47 times higher elevated thromboembolism and PE risk, respectively, within 7 days of a positive COVID-19 test (Table 3).

Results

Conclusion