722 - The Intensive Diet and Exercise for Arthritis Trial: 18-Month Clinical Outcomes

Sunday, November 6, 2011: 12:15 PM
W375d (McCormick Place West)
Stephen P. Messier1, Barbara J. Nicklas2, Claudine Legault3, Shannon Mihalko1, Gary D. Miller1, Paul DeVita4, Mary Lyles3, David J. Hunter5, Felix Eckstein6, Jeff D. Williamson3, J. Jeffery Carr3 and Richard F. Loeser1, 1Wake Forest University, Winston-Salem, NC, 2Winston-Salem, NC, 3Wake Forest University School of Medicine, Winston-Salem, NC, 4East Carolina University, Greenville, NC, 5Royal North Shore Hospital, Sydney, Australia, 6Paracelsus Medical University, Salzburg, Austria
Presentation Number: 722

Background/Purpose:  Obesity is the most prevalent modifiable risk factor, and dietary induced weight loss potentially the best non-pharmacologic treatment for symptomatic knee osteoarthritis (OA) symptoms. We report the clinical outcomes of a long-term study designed to test the hypothesis that intensive weight loss, either with or without exercise, will reduce pain and improve function compared to an exercise only control group in older, overweight and obese adults with symptomatic knee OA .

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.

Keywords: clinical trial, diet, exercise and weight loss

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.