COMPLIANCE TO EXERCISE THERAPY IN OLDER PARTICIPANTS WITH KNEE OSTEOARTHRITIS - IMPLICATIONS FOR TREATING DISABILITY

This investigation examined predictors of compliance with exercise the rapy in a clinical trial involving older adults with knee osteoarthrit is (OA). The study sample was partitioned into tertiles by level of co mpliance to determine its effect on several clinical outcome measures in the trial (i.e., knee pain, difficulty with activities of daily liv ing, and performance-related disability). The participants (N = 439) f irst completed all baseline assessments and were then randomly assigne d to one of three treatment conditions: health education control, aero bic exercise, or resistance exercise. The two exercise treatments invo lved a S-month center-based phase and a 15-month home-based phase. Var iables in five categories (i.e., demographic, fitness, health-related quality of life, performance-related disability, and prior exercise be havior) were entered as predictors of attendance and time spent exerci sing during each session for three different periods of time across th e course of the study. Results of these analyses revealed that it was possible to explain more Variance for time spent exercising (similar t o 40%) during the first 3 months than for attendance (similar to 10%). Furthermore, once participants completed the first 3 months of their training, prior behavior was the strongest predictor of exercise compl iance. In most cases, the regression models accounted anywhere from 26 to 46% of the variance in attendance or time spent exercising (7 of t he 8 P Values < 0.01). In general, demographic, fitness, psychosocial, and disability-related measures did not predict compliance with any c onsistency across the Various phases of the trial. Analysis of the dos e-response data suggest that, in the use of aerobic exercise to deter disability in older people with knee OA, consideration should be given to prescribing frequent bouts of activity (at least 3 times each week ) of moderate duration (similar to 35 min).