The Impact of Body Mass Index Classification on Outcomes After Stroke Rehabilitation

Abstract

With improving stroke mortality rates, more individuals are living with the consequences of stroke. Obesity is a known risk factor for stroke, but its effect on functional outcomes poststroke is less clear. The aim of this study was to determine the association between body mass index classification (underweight, normal weight, overweight, and obese) and functional outcomes, as measured by Functional Independence Measure change, Functional Independence Measure efficiency, and rehabilitation length of stay after inpatient stroke rehabilitation. A retrospective cohort study of individuals with a diagnosis of stroke admitted to a high-intensity inpatient rehabilitation program was performed. Patients were divided into 4 groups based on body mass index category using normal body mass index as the reference. Overall, 34 individuals (4.5%) were classified as underweight, 303 (40.1%) had body mass indices within the normal range, 269 (35.6%) were overweight, and 149 (19.7%) were obese. Ischemic stroke was the most common stroke type across all body mass index categories. Patients in the overweight and obese groups tended to be younger. There were no statistically significant differences in rehabilitation length of stay, Functional Independence Measure change, or Functional Independence Measure efficiency with all groups demonstrating significant functional improvements. Based on these findings, patients admitted for inpatient rehabilitation after stroke can be expected to make similar functional improvements regardless of BMI class.

Letter to the Editor on “The Impact of Body Mass Index Classification on Outcomes Following Stroke Rehabilitation: A Retrospective Study”

“…Many previous studies have reported the negative influence of age on the functional recovery after stroke. In the study by Weidman et al, 1 the age in the obese group was significantly lower than that of other groups (underweight, normal weight, and overweight). This younger age would play a positive role in functional recovery after stroke.…”

“…These previously mentioned issues decrease the reliability of the results of the study by Weidman et al 1 …”

“…Patients in the underweight group had the lowest admission FIM scores, which indicates that the recovery potential of patients in the underweight group could have been lower compared with those in other groups (normal weight, overweight, and obese). In the study by Weidman et al, 1 the statistical analysis was conducted without adjusting the admission FIM, and FIM change and FIM efficiency were not significantly different between the groups. The functional recovery was not significantly different between the groups, although the admission functional status was worst in the underweight group, which indicates that the rehabilitation effect could have been greater in the underweight group.…”

“…I read Weidman et al’s recently published article entitled “The impact of body mass index classification on outcomes following stroke rehabilitation: a retrospective study” with great interest 1 . The authors evaluated the association between body mass index (BMI) classification (underweight, normal weight, overweight, and obese) and functional outcomes, functional independence measure (FIM) changes and efficiency, and rehabilitation length of stay.…”

Authors’ Reply

“…To the Editors: W e thank Dr Chang for his interest in our article entitled "The impact of body mass index classification on outcomes following stroke rehabilitation: a retrospective study. 1 " Dr Chang noted that adjusted analyses were not performed in the study. Specifically, admission functional independence measure (FIM) score and age were not adjusted for when examining the association between body mass index (BMI) class and our outcomes.…”