Effect of Previous Anticoagulant Treatment on Risk of COVID-19

INTRODUCTION: Little is known about the role played by anticoagulants in COVID-19. OBJECTIVE: The aim of this study was to assess the impact of previous anticoagulant treatment on risk of hospitalization due to COVID-19, progression to severe COVID-19 and susceptibility to COVID-19 infection. METHODS: We conducted a multiple population-based case–control study in northwest Spain, in 2020, to assess (1) risk of hospitalization: cases were all patients admitted due to COVID-19 with PCR confirmation, and controls were a random matched sample of subjects without a positive PCR; (2) progression: cases were hospitalized COVID-19 subjects, and controls were all non-hospitalized COVID-19 patients; and (3) susceptibility: cases were patients with a positive PCR (hospitalized and non-hospitalized), and the controls were the same as for the hospitalization model. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using a generalized linear mixed model. RESULTS: The consumption of antivitamin K and direct-acting anticoagulants apparently was not associated with the risk of progression to severe COVID-19 (OR 0.93 [95% CI 0.74–1.17] and OR 1.04 [95% CI 0.79–1.36], respectively). Antivitamin K anticoagulants were associated with a significantly lower risk of hospitalization (OR 0.77 [95% CI 0.64–0.93]), which, in part, can be explained by a decreased risk of susceptibility to infection (OR 0.83 [95% CI 0.74–0.92]). The use of direct-acting anticoagulants was not associated with the risk of hospitalization, although it also seems to decrease susceptibility (OR 0.85 [95% CI 0.74–0.98]). It has also been observed that low-molecular-weight heparins were associated with an increased risk of progression to severe COVID-19 (OR 1.25 [95% CI 1.01–1.55]). CONCLUSION: The results of this study have shown that antivitamin K anticoagulants and direct-acting anticoagulants do not increase the risk of progression to more severe stages. Antivitamin K consumption was associated with a lower risk of hospitalization and susceptibility to infection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40264-022-01266-0.