Method: The Intensive Diet and Exercise for Arthritis trial (IDEA) was a prospective, single-blind, randomized controlled trial that enrolled 454 overweight and obese (BMI = 27-42 kg/m2) older (age ≥ 55 yrs) adults with pain and radiographic evidence of tibiofemoral OA (KL = 2-3). Participants were randomized to one of three 18-month interventions: intensive dietary restriction-only (D); intensive dietary restriction-plus-exercise (D+E); or exercise-only control (E). The weight loss goal for the two diet groups was ≥ 10% of baseline body weight, and the exercise intervention consisted of low to moderate intensity walking and resistance training 3 d/wk for 1 hr/d. We used an intention-to-treat analysis to compare changes between groups at 18 month follow-up (FU18) after adjusting for gender, baseline BMI, and baseline values of the dependent variable using repeated measures ANCOVA.
Result: Mean (SD) baseline descriptive characterisitics of the cohort included: age, 65.6 (6.2) yrs.; BMI, 33.6 (3.7) kg/m2; %female, 72; %white, 81. Bilateral knee OA was evident in 85% of the participants. A total of 399 (88%) participants completed the study (returned for FU18 testing). Mean weight loss was: D+E, 10.6 kg (11.4%); D, 8.9 kg (9.5%); E, 2.0 kg (2.2%). WOMAC pain (baseline, FU 18, %change) was significantly less (p < 0.0004) at FU18 in the D+E group (6.7,3.3; 51%) compared to the D (6.6, 4.8; 27%) and E (6.1, 4.4; 29%) groups. Similarly, WOMAC function was significantly (p = 0.003) better in the D+E group (24.6,13.0; 47%) relative to the D (24.8,17.3; 30%) and E (23.1,17.5; 24%) groups. Walking speed (m/s), our measure of mobility, was significantly (p = 0.004) faster in the D+E group (1.20, 1.34; 12%) than in the D (1.18, 1.30; 10%) and E (1.23, 1.30; 6%) groups. There was no significant difference between the groups on the SF-36 physical or mental health scales.
Conclusion: The IDEA trial shows that intensive weight loss with excellent long-term retention is possible in this population and, when combined with low to moderate intensity exercise, results in an approximate 50% reduction in pain accompanied by significant improvements in function and mobility. These data provide evidence that the best recommendation for long-term symptom reduction in overweight and obese persons with knee OA is intensive weight loss combined with low to moderate intensity exercise.
Disclosure: S. P. Messier, None; B. J. Nicklas, None; C. Legault, None; S. Mihalko, None; G. D. Miller, None; P. DeVita, None; M. Lyles, None; D. J. Hunter, None; F. Eckstein, Chondrometrics, 4 ; J. D. Williamson, None; J. J. Carr, None; R. F. Loeser, None.