Changes in Body Weight and Knee Pain in Adults With Knee Osteoarthritis Three‐and‐a‐Half Years After Completing Diet and Exercise Interventions: Follow‐Up Study for a Single‐Blind , Single‐Center , Randomized Controlled Trial

Objective To determine whether long-term diet (D) and exercise (E) interventions, alone or in combination (D+E), have beneficial effects for older adults with knee osteoarthritis (OA) 3.5 years after the interventions end. Methods This is a secondary analysis of a subset (n = 94) of the first 184 participants who had successfully completed the Intensive Diet and Exercise in Arthritis (IDEA) trial (n = 399) and who consented to follow-up testing. Participants were older (age >= 55 years), overweight, and obese adults with radiographic and symptomatic knee OA in at least 1 knee who completed 1.5-year D+E (n = 27), D (n = 35), or E (n = 32) interventions and returned for 5-year follow-up testing an average of 3.5 years later. Results During the 3.5-years following the interventions, weight regain in D+E and D was 5.9 kg (7%) and 3.1 kg (4%), respectively, with a 1-kg (1%) weight loss in E. Compared to baseline, weight (D+E -3.7 kg [P = 0.0007], D -5.8 kg [P < 0.0001], E -2.9 kg [P = 0.003]) and Western Ontario and McMaster Universities Osteoarthritis Index pain subscale scores (D+E -1.2 [P = 0.03], D -1.5 [P = 0.001], E -1.6 [P = 0.0008]) were lower in each group at the 5-year follow-up. The effect of group assignment at the 5-year follow-up was significant for body weight, with D being less than E (-3.5 kg; P = 0.04). Conclusion Older adults with knee OA who completed 1.5-year D or D+E interventions experienced partial weight regain 3.5 years later; yet, relative to baseline, they preserved statistically significant changes in weight loss and reductions in knee pain.