Risk of atrial fibrillation in patients with systemic sclerosis: a nationwide population-based study.

Objective: Atrial fibrillation (AF) is the most common arrhythmia in the general population, causing substantial economic burden, morbidity and mortality. The incidence rate and risk of AF in patients with SSc are unclear. We aimed to assess the incidence rate of AF in patients with SSc and the risk of incident AF in patients with SSc compared with the general population.

Methods: The Korean National Health Insurance Service database was used as the data source. Patients with claims data for SSc between 2010 and 2017 were extracted from the database along with 1:5 age- and sex-matched controls. The index date was the earliest date with claims data for SSc between 2010 and 2017. The follow-up duration was from the index date to 2019. Multivariable Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% CI for AF in patients with SSc.

Results: Overall, 2519 patients with SSc and 12 595 age- and sex-matched controls were included. Over a mean follow-up duration of 5.2 years (s.d. 2.6), the incidence rates of AF were 3.52 and 1.68 per 1000 person-years for patients with SSc and controls, respectively. Compared with controls, patients with SSc had a significantly higher risk of incident AF [adjusted HR 2.095 (95% CI 1.466, 2.994)].

Conclusion: Patients with SSc had a 2-fold higher risk of incident AF than controls. Given the significant economic burden, morbidity and mortality that AF poses, close monitoring for incident AF in patients with SSc is warranted.