Impact of atrial fibrillation on mortality and non-fatal cardiovascular outcomes in 145 293 patients admitted with COVID-19: a statewide population-linkage study

Abstract

Abstract Background Atrial fibrillation (AF) is common in COVID-19 patients. The impact of AF on major-adverse-cardiovascular-events (MACE defined as all-cause mortality, myocardial infarction, ischaemic stroke, heart failure or revascularisation), recurrent admission with AF and venous thromboembolism in patients hospitalised with COVID-19 is not well-defined. Purpose This study aims to examine the impact of AF on long-term clinical outcomes including fatal and non-fatal cardiovascular outcomes in patients admitted with COVID-19. Methods Patients admitted with COVID-19 (1 January 2020 to 30 September 2021) were identified from the Admitted-Patient-Data-Collection database in New South Wales, the largest state of Australia, stratified by AF status (No-AF vs Prior-AF or New-AF during index COVID-19 admission) and followed up until 31 March 2022. A linkage look-back to year 2001 was performed to identify prior-AF history. Multivariable Cox regression was performed to assess the impact of AF status on MACE. To account for the competing risk of death and assess the impact of AF on non-fatal cardiovascular outcomes, Fine-Gray competing risk analysis was performed. Results The cohort comprised 145 293 COVID-19 patients (median age 67.4 years; 49.7% males): New-AF, n=5 140 (3.5%); Prior-AF, n=23 204 (16.0%) (Table 1). During a median follow-up of 9 months, Prior-AF and New-AF patients had significantly higher MACE rates (Prior-AF: 44.7% vs New-AF: 36.2% vs No-AF: 18.0%), including all-cause mortality (Prior-AF: 36.0% vs New-AF: 28.7% vs No-AF: 15.2%) compared to No-AF patients (both logrank P<0.001). After adjusting for age, gender, intensive-care-unit admission and Charlson comorbidity index, compared to No-AF status, New-AF and Prior-AF status were independently associated with MACE (adjusted hazard ratio[aHR]=1.17, 95% confidence interval [CI]=1.11-1.22; aHR=1.36, 95%CI=1.33-1.40 respectively; both P<0.001). Competing risk analyses showed that rehospitalisation rates for ischaemic stroke, heart failure and AF but not venous thromboembolism were significantly higher in COVID-19 patients with New-AF and Prior-AF (P<0.001) (Table 2). In a separate competing risk analysis incorporating patient’s CHA2DS2VASc status, New-AF patients had a higher rehospitalisation rate for ischaemic stroke, independent of CHA2DS2VASc group (CHA2DS2VASc=0 vs CHA2DS2VASc≥1: subdistribution HR [sHR]=3.57 and 1.61 respectively), whereas patients with Prior-AF had a higher rehospitalisation rate for ischaemic stroke only if CHA2DS2VASc≥1 (sHR=1.34) (all P<0.05). Conclusions COVID-19 patients with AF are at high risk of MACE and other adverse clinical outcomes. Such patients could be targeted for increased surveillance and additional post-discharge support. Efficacy of early anticoagulation for COVID-19 patients with new-AF to prevent stroke regardless of CHA2DS2VASc score requires further study.Table 1.Baseline characteristicsTable 2.Non-fatal CV outcomes