Covid-19 and comedications in atrial fibrillation – a case-control study in Stockholm

Abstract

ObjectivesTo test the main hypothesis that anticoagulation reduces risk of hospitalization, intensive care unit (ICU) admission and death in COVID-19.DesignNested case-control study among patients with atrial fibrillation (AF) in Stockholm. Cases were matched to five controls with same sex, born within +/- 1 years, and without COVID-19.SettingSource population was individuals in Stockholm with AF 1997-2020. Swedish regional and national registers are used. National registers cover hospitals and outpatient clinics, local registers cover primary care. Records were linked through the personal identity number assigned to each Swedish resident.ParticipantsCases were individuals with diagnosis of, ICU admission for, or death with COVID-19. The source population consisted of 179,381 individuals from which 7,548 cases were identified together with 37,145 controls. The number of cases (controls) for hospitalization, ICU admission and death were 5,916 (29,035), 160 (750) and 1,472 (7,360). The proportion of women was 40% for hospitalization and death, but 20% and 30% for admission to ICU in wave one and two, respectively. Main outcome measuresPrimary outcome was mortality, secondary outcome was hospitalization, tertiary outcome was ICU admission, all with COVID-19.ResultsOdds ratios (95% confidence interval) for antithrombotics were 0.79 (0.66 to 0.95) for the first wave and 0.80 (0.64 to 1.01) for the second wave.ConclusionsUse of anticoagulation among patients with COVID-19 and arrythmias is associated with lower risk of hospitalization and death. If further COVID-variants emerge, or other infections with prothrombotic properties, this emphasize need for physicians to ensure compliance among vulnerable patients.