The Effect of Body Mass Index on Pulmonary Related Debility Rehabilitation

Background: Obesity is a known factor for the development of abnormal respiratory physiology. However, several studies have found that obesity does not hinder functional recovery in patients hospitalized for postacute care following a stroke or cardiovascular event. This study was designed to determine the effect of overweight and obesity on patients with acute pulmonary disease, hospitalized in an inpatient rehabilitation facility (IRF). Objective: To investigate the impact of body mass index (BMI) on indices of function, specifically, the functional independence measure (FIM) among patients with pulmonary related debility admitted to a rehabilitation hospital. Design: Retrospective cohort study. Setting: Pulmonary unit in an acute freestanding rehabilitation hospital. Patients: All patients admitted to an IRF with a diagnosis of pulmonary related debility over a 6-year period. Methods: The data used in the study included the patient height and weight (measured on admission) and FIM (scored on admission and discharge). Main Outcome Measures: The primary study outcome measure was the change in FIM per day by the patients' BMI category. Results: For the 381 patients admitted during the observation period, BMI was compared with FIM score changes per day (FIM efficiency). After adjusting for age and sex, the FIM efficiency only slightly differed by BMI, failing to reach statistical significance. However, age did significantly influence the outcome (P =.05). Conclusion: This study demonstrates that among a large group of patients with a pulmonary related debility, there was no statistically significant correlation between BMI and FIM efficiency. The overweight patients were similar in progression to those who were underweight, normal weight, and obese. However, this study found that increased age adversely affected the outcome of rehabilitation. Level of Evidence: III.