Low Body Mass Index is a Poor Prognosis Factor in Cardioembolic Stroke Patients with NonValvular Atrial Fibrillation

Background: The relationship between body mass index (BMI) and the severity of cardioembolic stroke (CES) remains poorly understood. Method: A total of 419 consecutive CES patients with nonvalvular atrial fibrillation (NVAF), and with a modified Rankin Scale (mRS) score of 0 or 1 before onset admitted within 48 hours after onset to the Hirosaki Stroke and Rehabilitation Center were studied. The patients were divided into three groups, low BMI (L-BMI; n = 36, BMI < 18.5 kg /m(2)), normal BMI (N-BMI; n = 284, 18.5 <= BMI < 25.0), and high BMI (H-BMI; n = 99, BMI >= 25.0). We compared stroke severity and functional outcome among the three groups. Results: Stroke severity on admission, assessed by the National Institutes of Health Stroke Scale (NIHSS) showed that patients with L-BMI had the highest NIHSS score (median, 16 [11-25]), followed by N-BMI and H-BMI (11 [5-19] and 9 [3-19], P = .002). Functional outcome at discharge, assessed by mRS, was most severe in L-BMI patients (5 [3-5]), followed by N-BMI and H-BMI (3 [1-4] and 2 [1-4], P = .001). Multivariate analyses revealed that L-BMI was a significant determinant of severe stroke (NIHSS scores >= 8) at admission (odds ratio [OR] to N-BMI = 2.79, 95% confidence interval [CI], 1.17-7.78, P = .02) and poor functional outcome (mRS scores >= 3) at discharge (OR = 2.53, 95% CI, 1.12-6.31, P = .02). However, H-BMI did not affect stroke severity at admission or functional outcome at discharge. Conclusion: Low BMI is a risk factor for severe stroke on admission and unfavorable functional outcome at discharge in Japanese CES patients with NVAF.