The association between anticoagulation and adverse outcomes after a positive SARS-CoV-2 test among older outpatients: A population-based cohort study. Issue 211 (March 2022)

• Record Type: Journal Article
• Authors: Abdel-Qadir, Husam; Austin, Peter C.; Pang, Andrea; Fang, Jiming; Udell, Jacob A.; Geerts, William H.; McNaughton, Candace D.; Jackevicius, Cynthia A.; Kwong, Jeffrey C.; Yeh, Calvin H.; Cox, Jafna L.; Lee, Douglas S.; Ko, Dennis T.; Atzema, Clare L.
• Is Part Of: Thrombosis research. Issue 211(2022)
• Page Start: 114
• Page End: 122
• Publication Date: 2022-03
• Subjects: SARS-CoV-2 -- Coronavirus disease 2019 (COVID-19) -- Anticoagulants -- Mortality -- Hospitalization; Thrombosis -- Periodicals; 616.135
• DOI: 10.1016/j.thromres.2021.12.010
• Languages: English
• ISSNs: 0049-3848

Abstract

Abstract: Introduction: Anticoagulation may improve outcomes in patients with COVID-19 when started early in the course of illness. Materials and methods: This was a population-based cohort study using linked administrative datasets of outpatients aged ≥65 years old testing positive for SARS-CoV-2 between January 1 and December 31, 2020 in Ontario, Canada. The key exposure was anticoagulation with warfarin or direct oral anticoagulants before COVID-19 diagnosis. We calculated propensity scores and used matching weights (MWs) to reduce baseline differences between anticoagulated and non-anticoagulated patients. The primary outcome was a composite of death or hospitalization within 60 days of a positive SARS-CoV-2 test. We used the Kaplan-Meier method and cumulative incidence functions to estimate risk of the primary and component outcomes at 60 days. Results: We studied 23, 159 outpatients (mean age 78.5 years; 13, 474 [58.2%] female), among whom 3200 (13.8%) deaths and 3183 (13.7%) hospitalizations occurred within 60 days of the SARS-CoV-2 test. After application of MWs, the 60-day risk of death or hospitalization was 29.2% (95% CI 27.4%–31.2%) for anticoagulated individuals and 32.1% (95% CI 30.7%–33.5%) without anticoagulation (absolute risk difference [ARD], −2.9%; p = 0.005). Anticoagulation was also associated with a lower risk of death: 18.6% (95% CI 17.0%–20.2%) with anticoagulation and 20.9% (95% CI 19.7%–22.2%) in non-anticoagulated patients (ARD -2.3%; p = 0.005). Conclusions: Among outpatients aged ≥65 years, oral anticoagulation at the time of a positive SARS-CoV-2 test was associated with a lower risk of a composite of death or hospitalization within 60 days. Highlights: This was a population-based cohort study of older patients diagnosed with COVID-19. Anticoagulation at time of COVID-19 diagnosis was associated with improved outcomes. Early anticoagulation in high-risk outpatients merits study in a randomized controlled trial.