A U-shaped relationship between body mass index and functional recovery in older Japanese stroke survivors undergoing hospital rehabilitation

Abstract

ObjectiveA relationship between body mass index and functional recovery in older survivors of stroke is unclear. Therefore, this study aimed to investigate the association of body mass index with post-stroke functional recovery in older Japanese stroke survivors undergoing hospital rehabilitation. MethodsThis was a multicenter retrospective observational study of 757 older survivors of stroke, from six convalescent rehabilitation hospitals in Japan. The participants were classified into seven categories according to body mass index at admission. The measurements included outcomes of the absolute gain in the motor subscale of the Functional Independence Measure. Poor functional recovery was defined as gain < 17 points. Multivariate logistic regression analysis was performed to examine the impact of these body mass index categories on poor functional recovery. ResultsThe mean motor gains were highest in the 23.5–25.4 kg/m2 group (28.1 points), and lowest in the < 17.5 kg/m2 group (220.0 points). The results of the multivariate regression analyses (reference; 23.5–25.4 kg/m2 group) showed that the < 17.5 kg/m2 group (odds ratios 4.30; 95 % confidence intervals 2.09–8.87), the 17.5–19.4 kg/m2 group (1.99; 1.03–3.87), the 19.5–21.4 kg/m2 group (1.93; 1.05–3.54), and the ≥ 27.5 kg/m2 group (3.34; 1.33–8.42) were significantly associated with poor functional recovery, but not in the other groups. ConclusionsOlder survivors of stroke with high-normal weight had the most favorable functional recovery among the seven groups. Meanwhile, both low and extremely high body mass indexes were associated with poor functional recovery.