Rural–urban and geographical differences in prognosis of atrial fibrillation in Finland : a nationwide cohort study

Aims: Rural–urban disparities have been reported in the outcomes of cardiovascular diseases. We assessed whether rural–urban or other geographical disparities exist in the risk of ischemic stroke (IS) and death in patients with atrial fibrillation (AF) in Finland. Methods: The registry-based FinACAF cohort study covers all patients with AF from all levels of care in Finland from 2007 to 2018. Patients were divided into rural–urban categories and into hospital districts (HDs) based on their municipality of residence. Results: We identified 222,051 patients (50.1% female; mean age 72.8 years; mean follow-up 3.9 years) with new-onset AF, of whom 15,567 (7.0%) patients suffered IS and 72,565 (32.7%) died during follow-up. The crude IS rate was similar between rural and urban areas, whereas the mortality rate was lower in urban areas (incidence rate ratios (IRRs) with 95% confidence intervals (CIs) 0.97 (0.93–1.00) and 0.92 (0.91–0.93), respectively). However, after adjustments, urban residence was associated with slightly higher IS and mortality rates (IRRs with 95% CIs 1.05 (1.01–1.08) and 1.06 (1.04–1.07), respectively). The highest crude IS rate was in the East Savo HD and the lowest in Åland, whereas the highest crude mortality rate was in the Länsi-Pohja HD and the lowest in the North Ostrobothnia HD (IRRs with 95% CIs compared to Helsinki and Uusimaa HD for IS 1.46 (1.28–1.67) and 0.79 (0.62–1.01), and mortality 1.24 (1.16–1.32) and 0.97 (0.93–1.00), respectively. Conclusions: Rural–urban differences in prognosis of AF in Finland appear minimal, whereas considerable disparities exist between HDs.