Body Mass Index and Poststroke Mortality

Obesity is an established cardiovascular risk factor. We studied the association between body mass index (BMI) and all-cause mortality after stroke.A registry started in 2001 with the aim to register all hospitalized stroke patients in Denmark now includes 21,884 patients in whom BMI was recorded. There are five BMI groups: underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), obese (BMI 30.0-34.9) and severely obese (BMI > or = 35). All patients underwent an evaluation including stroke severity, computed tomography, and cardiovascular risk factors. Survival was followed up to 5 years after stroke (median 1.5 years). Independent predictors of death were identified by means of a survival model based on 13,242 individuals with a complete data set.Compared to normal-weight patients, mortality was lower in overweight [hazard rate (HR) 0.73, 95% CI 0.66-0.81], obese (HR 0.84, 95% CI 0.73-0.98) and severely obese stroke patients (HR 0.84, 95% CI 0.64-1.10), while mortality was higher in underweight patients (HR 1.63, 95% CI 1.41-1.90).Poststroke mortality is inversely related to BMI: overweight and obese stroke patients have a lower poststroke mortality rate than normal-weight and underweight patients.