Increased risk of atrial fibrillation among patients with bullous pemphigoid: a nationwide cohort study in Taiwan

Background Bullous Pemphigoid (BP) and Atrial Fibrillation (AF) share common underlying mechanisms involving chronic inflammation, but their relationship was unclear. Objective To assess the risk of incident AF in individuals with BP. Methods This nationwide cohort study utilized Taiwan’s National Health Insurance Research Database from 2011 to 2019. Adults newly diagnosed with BP were identified and initially matched by age and sex to controls without BP. Stabilized inverse probability weighting was applied to balance baseline characteristics between cohorts. Cox proportional hazards models were used to estimate Hazard Ratios (HRs) and 95% Confidence Intervals (95% CIs) for incident AF. Subgroup analyses were performed by age and sex, along with several sensitivity analyses. Results During the follow-up period, AF occurred in 510 of the 9,554 patients in the BP group and 1,902 of the 52,015 individuals in the non-BP group, corresponding to an incidence of 15.03 and 7.99 per 1,000 person-years, respectively. BP was associated with an increased risk of incident AF (HR 1.83; 95% CI 1.66–2.02). This association persisted across analyses stratified by age and sex. The findings were consistent across multiple sensitivity analyses. Study limitations The unavailability of data on potential confounders such as lifestyle factors (smoking, alcohol, obesity) and disease severity. Conclusions BP is linked to a heightened risk of AF. Prompt recognition of AF and timely cardiology referrals may be warranted in BP patients presenting with suggestive symptoms.