The Relationship Between the Body Mass Index and In-Hospital Mortality in Patients Admitted for a Stroke

Background: While obesity has been shown to be associated with increased incidence and severity of major cardiovascular risk factors and elevated risk for stroke, studies examining its effect on outcomes in stroke victims have shown conflicting results. We aimed at describing the BMI distribution in a nationwide cohort of patients, admitted for a stroke and the relationship between BMI and in-hospital mortality.

Methods: We drew data from the U.S. National Inpatient Sample (NIS), to identify cases of stroke, between October 2015 and December 2016. The patients were divided into 6 groups based on their BMI (underweight, normal weight, overweight, obese I, obese II, extremely obese). Socio-demographic and clinical data were collected, and incidence of mortality and length of stay were analyzed. Multivariate analysis was performed to identify independent predictors of mortality.

Results: Among a weighted total of 84185 hospitalizations for stroke in patients with documented BMI, the mean age was 65.5+31 years, majority of patients (55.3%) were female and 63.1% were white. The overall rate of in-hospital mortality during the study period was 3.6%. A U-shaped relationship between the BMI and in-hospital mortality was documented, as patients with 250, p<0.05.

Conclusion: A U-shaped relationship between the BMI and in-hospital mortality was documented in patients hospitalized for a stroke in the U.S. in the recent years in a nationwide dataset. These findings support the existence of an “obesity paradox” in patients hospitalized following a stroke, similarly to described in other cardiovascular conditions.