The obesity paradox may not lead to functional gains in stroke patients undergoing acute inpatient rehabilitation.

Abstract

Obesity is a risk factor for many adverse health outcomes. However for some cardiac conditions and cancers, evidence of an "obesity paradox" seems to exist where an elevated body mass index (BMI) is linked to protective effects in mortality and functional outcomes. Within the stroke rehabilitation literature, there are conflicting findings on this phenomenon possibly due to unaccounted for variables, such as comorbid medical conditions. To investigate the association between BMI and functional gains made in acute inpatient stroke rehabilitation, and the effects of multiple confounding variables. Retrospective cohort study. Tertiary academic hospital. Three hundred ninety-two adults following a recent ischemic (82%) or hemorrhagic (18%) stroke with a mean age 62.9 years. Acute inpatient rehabilitation. Functional Independence Measure (FIM) score and BMI. A significant association was found between motor FIM score gains and elevated BMI when BMI was treated as a continuous variable (p < .05). However, this association disappeared when patient factors and comorbid conditions were taken into account and when BMI was conceptualized categorically (underweight [BMI <18.5], normal [BMI 18.5-24.9], overweight [BMI 25.0-29.9], obese [BMI 30.0-39.9], and severely obese [BMI ≥40.0]). Advanced age, higher motor function on admission, and a diagnosis of diabetes were all significantly associated with decreased motor FIM gains. The results from this study provide insufficient evidence to support the "obesity paradox" once patient factors and comorbid conditions are taken into account. Diabetes was the single comorbidity tracked that showed a significant association with change in motor function (p = .01). Further studies might explore how the unique interventions of rehabilitation physicians and ancillary health professionals might mitigate the functional debility associated with diabetes and obesity in stroke patients.