Functional Performance, Mobility-Related Self-efficacy, and Physical Activity In Older, Overweight and Obese Knee Osteoarthritis Patients

Abstract

Knee osteoarthritis (OA) is one of the leading causes of functional limitations and activity restriction among older adults. Being overweight or obese may exacerbate the risk of functional decline and inactivity among knee OA patients. However, it has yet to be determined if risk of functional decline and inactivity differs as a function of weight status among older, knee OA patients. PURPOSE: The purpose of this investigation was to examine differences in functional performance, mobility-related self-efficacy, and objectively measured physical activity among overweight, obese, and morbidly obese older adults with knee OA. METHODS: Seventy-one (58 women and 13 men; M age = 63 years) knee OA patients classified as overweight (n=20), obese (n=36) or morbidly obese (n=13) completed assessments of 400 meter walk performance, mobility-related self-efficacy (SE), and pedometer-determined physical activity (PA). RESULTS: Results of univariate ANCOVA analyses controlling for age revealed that morbidly obese participants demonstrated significantly worse 400 meter walk time (p < 0.01), lower mobility-related SE (p < 0.01), and engaged in less PA (p < 0.01) compared to overweight or obese participants. Obese patients also participated in significantly less PA (p < 0.05) relative to participants classified as overweight. Results of partial correlation analyses controlling for age also revealed that 400 meter walk time was inversely correlated with mobility-related SE (r = -.65; p < 0.01) and pedometer-determined PA (r = -.50; p < 0.01). CONCLUSIONS: These findings suggest that risk for functional decline and inactivity increases as a function of weight status among older knee OA patients. Morbidly obese patients demonstrated the least favorable functional performance, mobility-related SE, and PA. The results also demonstrate that worse functional performance is associated with lower mobility-related SE and PA participation. Collectively, the present findings indicate benefits of lower weight for both mobility self-efficacy and objective functional performance among older adults with knee OA. Supported by NIH/NIAMS R21 AR054595