Background: Japanese patients with atrial fibrillation (AF) are generally small and lean, but knowledge of the clinical characteristics of those with low body weight (LBW: ≤50 kg) is limited.
Methods and results: The Fushimi AF Registry is a community-based prospective survey of AF patients who visited the participating medical institutions in Fushmi-ku, Japan. The BW and follow-up data were available for 2,945 patients. We compared the background and the incidence of clinical events during a median follow-up of 746 days between a LBW and non-LBW group. Patients in the LBW group accounted for 26.8% (788 patients) of the total. The LBW group was more often female, older, and had higher CHADS2score. The incidence of stroke/systemic embolism (SE) during follow-up was higher in the LBW group (hazard ratio (HR): 2.19, 95% confidence interval (CI): 1.57-3.04; P<0.01), whereas that of major bleeding was comparable (HR: 1.05, 95% CI: 0.64-1.68; P=0.84). This trend was consistently observed in the subgroups stratified by age, sex, and oral anticoagulant prescription at baseline. Multivariate analysis as well as propensity-score matching analysis further supported the significance of LBW as a risk of stroke/SE.
Conclusions: Patients in the LBW group had high risk profiles and showed a higher incidence of stroke/SE, but the incidence of major bleeding was not particularly high.