The Veterans Health Administration (VHA) clinical practice recommendations endorse a power mobility device (PMD) for individuals with adequate judgment, cognitive ability, and vision who are unable to propel a manual wheelchair or walk community distances despite standard medical and rehabilitative interventions.1 VHA supports the use of a PMD in order to access medical care and accomplish activities of daily living, both at home and in the community for veterans with mobility limitations secondary to cardiovascular disease, neurologic disorders, pulmonary disease, or musculoskeletal disorders. The goal of a PMD use is increased participation in community and social life, improved health maintenance via enhanced access to medical facilities, and an overall enhanced quality of life. However, there is a common concern among health care providers that prescribing a PMD may decrease physical activity, in turn, leading to obesity and increasing morbidity. 2
The prevalence of obesity is increasing in the United States. In the past decade 35.0% of men and 36.8% of women were classified as obese (body mass index [BMI], ≥ 30).3 Recent figures from the Centers for Disease Control and Prevention estimate that the overall prevalence of obesity in Americans is closer to 42.4%.4 The veteran population is not immune to this; a 2014 study of nearly 5 million veterans reported that the prevalence of obesity in this population was 41%.5,6 In addition to obesity being implicated in exacerbating many medical problems, such as osteoarthritis, insulin resistance, and heart disease, obesity also is associated with a significant decrease in lifespan.7 Almost half of adults who report ambulatory dysfunction are obese.8 Given the increased morbidity and mortality as a result of obesity, interventions that may promote weight gain need to be appropriately identified and minimized.
In a retrospective study of 89 veterans, Yang and colleagues demonstrated no significant weight change 1 year after initial PMD prescription.2 Another study of 102 patients noted no significant weight changes 1 year after PMD prescription.9 This study analyzes the effect of PMD prescriptions over a 2-year period on BMI and body weight in a larger population of veterans both as a whole and in BMI/age subgroups.
Methods
The institutional review board at Hunter Holmes McGuire Veterans Affairs Medical Center in Richmond, Virginia, reviewed and approved this study. A waiver of participant consent was approved due to the nature of the research (medical records of patients, some of whom were deceased) and the type of data collected (retrospective data). In addition, each individual was assigned a sequential code to de-identify any personal information. Prosthetics department medical records of consecutive veterans who received PMDs for the first time between January 1, 2011 and June 30, 2012, were reviewed.
Data extracted from the electronic health record (EHR) included demographics, indication for power mobility, weight at time of PMD prescription, weight at 2-years postprescription, and height. Weight readings were considered valid if weight was taken within 3 months of initial prescription and then again within 3 months at the 2-year interval. Individuals without weights recorded in these time frames were excluded. In addition, we excluded medical conditions that might significantly affect body weight, including amyotrophic lateral sclerosis (ALS), amputation during the study period, or history of weight loss surgery. Cancer diagnoses were excluded as they were not an indication for power mobility in the VHA. ALS, though variable in its disease course, was specifically excluded given the likelihood of these patients dying of the natural progression of the disease before the 2-year follow-up period: Median survival times in patients diagnosed with ALS aged > 60 years was < 15 months. 10-12
The EHRs of 399 individuals who received a PMD during the period were reviewed, and 185 veterans met criteria for data analysis. Subject exclusions in the weight and BMI analysis included death during the follow-up period (89), missing data (68), prior PMD users who came in for replacements (53), and ALS (4) (Figure 1). Patients were not excluded based on the presence or absence of intentional weight loss efforts as this information was not readily available through chart review.
Statistical Analysis
The primary outcome measure was the change in BMI and body weight from time 1 (date of PMD prescription) to time 2 (2 years later). Analyses were performed using IBM SPSS Statistics, Version 21. BMI was calculated using the weight (lb) x 703/ (height [inches]).2 Dichotomization of BMI was performed using the conventional cut scores: < 30.0, not obese; and ≥ 30.0, obese. Paired t tests and SPSS general linear model (repeated measures) were used to examine change of BMI from time 1 to time 2. The exact McNemar test was used to examine change in obesity classification across time 1 and time 2. Correlating with Yang’s retrospective observational study, data were analyzed separately for aged < 65 years and aged≥ 65 years.2