Reduction in All-cause Mortality in COVID-19 Patients on Chronic Oral Anticoagulation: A Population-based Propensity Score Matched Study

Background: Coronavirus disease 2019 (COVID-19) global pandemic has strikingly high mortality rate with hypercoagulability state being part of the imputed mechanisms. We aimed to compare the rates of in hospital mortality in propensity score matched cohorts of COVID-19 patients in chronic anticoagulation versus those that were not.

Methods: In this population-based study in the Veneto Region, we retrospectively reviewed all patients aged 65 years or older, with a laboratory-confirmed COVID-19 diagnosis. We compared, after propensity score matching, those who received chronic anticoagulation for atrial fibrillation with those who did not.

Results: Overall, 4697 COVID-19 patients fulfilled inclusion criteria, and the propensity score matching yielded 559 patients per arm. All-cause mortality rate ratio was significantly higher among non-anticoagulated patients (32.2% vs 26.5%, p = 0.036). On time to event analysis, all-cause mortality was found lower among anticoagulated patients, although the estimate was not statistically significant. (HR 0.81, 95%CI 0.65-1.01, p = 0.054).

Conclusion: Among elderly patients with COVID-19, those on chronic oral anticoagulant treatment for atrial fibrillation seem to be at lower risk of all-cause mortality compared to their propensity score matched non-anticoagulated counterpart. This finding needs to be confirmed in further studies.