Autoimmune diseases (ADs) are associated with an increased risk of developing certain cardiac arrhythmias. However, their prognostic effect in patients with cardiac arrhythmias has not been comprehensively investigated. We aimed to assess the association between ADs and prognosis in this population.

Based on a large retrospective observational cohort, this study included patients with various cardiac arrhythmias, including atrial fibrillation/atrial flutter (AF/AFl), ventricular tachycardia/ventricular fibrillation (VT/VF), and bradyarrhythmias. ADs were considered an exposure factor. The endpoint was all-cause mortality. Cox proportional hazards regression analyses were performed to calculate hazard ratios (HR) and 95% confidence intervals (95%CI) to quantify associations. Propensity score matching was used to mitigate potential confounding bias.

The analysis included 14 225 patients (mean age, 73.9±12.5 years, 59.2% women), of whom 4552 (32.0%) died within 1 year of discharge. After adjustment for various covariates, patients with ADs showed a higher risk of mortality in AF/AFl (HR, 1.23; 95%CI, 1.1-1.33; P<.001) and VT/VF (HR, 1.28; 95%CI, 1.02-1.60, P=.032). For bradyarrhythmias, although a potential association was observed, the trend did not reach statistical significance (HR, 1.20; 95%CI, 0.93-1.56; P=.168). The association persisted among multiple sensitivity analyses and remained consistent after adjustment for a wide range of covariates.

ADs were significantly associated with an increased risk of all-cause mortality in patients with cardiac arrhythmias, particularly in those with AF/AFl and VT/VF.