Impact of hemoglobin concentration and platelet count on outcomes of patients with non-valvular atrial fibrillation: A subanalysis of the J-RHYTHM Registry

Background To clarify the influence of hemoglobin concentration and platelet count on adverse outcomes of Japanese patients with non-valvular atrial fibrillation (NVAF), a post hoc analysis of the J-RHYTHM Registry was performed. Methods A consecutive series of outpatients with atrial fibrillation were enrolled from 158 institutions and followed up for 2 years or until an event occurred (thromboembolism, major hemorrhage, or all-cause death). Among 7406 patients with NVAF, 6536 with complete blood count data (69.8 ± 9.9 years, 71.0% men) were divided into 4 groups according to the baseline hemoglobin level (<10.0, 10.0–11.9, 12.0–13.9, and ≥14.0 g/dL) or platelet count (<10.0, 10.0–19.9, 20.0–29.9, and ≥30.0 × 10 4 /μL). Results Incidence rates of major hemorrhage (p = 0.004 for trend), all-cause death (p < 0.001 for trend), and composite events (p < 0.001 for trend) increased as hemoglobin levels decreased, and composite events (p = 0.045 for trend) increased as platelet counts decreased. After adjusting for multiple confounders, the incidence of all-cause death and composite events was higher with hemoglobin levels <12.0 g/dL than a hemoglobin level ≥14.0 g/dL. In contrast, platelet count was not associated with any events. This was also true when multivariate analysis was performed using the stepwise forward method. Conclusions A low hemoglobin level (<12.0 g/dL) was an independent risk factor for all-cause death and composite events in Japanese patients with NVAF. However, platelet count did not impact outcomes. Clinical trial registration: http://www.umin.ac.jp/ctr/ (unique identifier: UMIN000001569).