Evaluation of antithrombotic use and COVID-19 outcomes in a nationwide atrial fibrillation cohort

Abstract

Objective: To evaluate antithrombotic (AT) use in individuals with atrial fibrillation (AF) and at high risk of stroke (CHA₂DS₂-VASc score ≥2) and investigate whether pre-existing AT use may improve COVID-19 outcomes.

Methods: Individuals with AF and CHA₂DS₂-VASc score ≥2 on 1 January 2020 were identified using electronic health records for 56 million people in England and were followed up until 1 May 2021. Factors associated with pre-existing AT use were analysed using logistic regression. Differences in COVID-19-related hospitalisation and death were analysed using logistic and Cox regression in individuals with pre-existing AT use versus no AT use, anticoagulants (AC) versus antiplatelets (AP), and direct oral anticoagulants (DOACs) versus warfarin.

Results: From 972 971 individuals with AF (age 79 (±9.3), female 46.2%) and CHA₂DS₂-VASc score ≥2, 88.0% (n=856 336) had pre-existing AT use, 3.8% (n=37 418) had a COVID-19 hospitalisation and 2.2% (n=21 116) died, followed up to 1 May 2021. Factors associated with no AT use included comorbidities that may contraindicate AT use (liver disease and history of falls) and demographics (socioeconomic status and ethnicity). Pre-existing AT use was associated with lower odds of death (OR=0.92, 95% CI 0.87 to 0.96), but higher odds of hospitalisation (OR=1.20, 95% CI 1.15 to 1.26). AC versus AP was associated with lower odds of death (OR=0.93, 95% CI 0.87 to 0.98) and higher hospitalisation (OR=1.17, 95% CI 1.11 to 1.24). For DOACs versus warfarin, lower odds were observed for hospitalisation (OR=0.86, 95% CI 0.82 to 0.89) but not for death (OR=1.00, 95% CI 0.95 to 1.05).

Conclusions: Pre-existing AT use may be associated with lower odds of COVID-19 death and, while not evidence of causality, provides further incentive to improve AT coverage for eligible individuals with AF.

Keywords: COVID-19; atrial fibrillation; drug monitoring; electronic health records; epidemiology.

Figure 1

Visual overview of key study findings. AC, anticoagulants; AF, atrial fibrillation; AP, antiplatelets; AT, antithrombotics; DOACs, direct oral anticoagulants; IMD, Index of Multiple Deprivation; NSAIDs, non-steroidal anti-inflammatory drugs.

Figure 2

Individual antithrombotic prescriptions by drug category, January 2020–May 2021. AC, anticoagulants; AP, antiplatelets; AT, antithrombotics.

Figure 3

Factors associated with antithrombotics versus no antithrombotics (1 January 2020), using multivariable logistic regression. BMI, body mass index; IMD, Index of Multiple Deprivation; NSAIDs, non-steroidal anti-inflammatory drugs.

Figure 4

Comparison of AT medication exposures on COVID-19 outcomes (followed up to 1 May 2021) using propensity score adjusted multivariable logistic regression. AC, anticoagulants; AP, antiplatelets; AT, antithrombotics; DOACs, direct oral anticoagulants.