Magnitude of weight loss and structural progression of knee osteoarthritis in adults with obesity - A prospective cohort study
Background: Obesity is the major modifiable risk factor for knee osteoarthritis (OA) but the amount of weight loss needed to reduce structural progression in the real world is not well defined. Materials and Methods: In this single-center prospective cohort study, 400 adults with obesity (body-mass index [BMI] (cid:21) 30 kg/m 2 ) and Kellgren–Lawrence grade 2–3 knee OA were enrolled and assessed at baseline and 12 months. The main outcome was structural progressors, defined as those with a loss in medial femorotibial cartilage thickness of (cid:21) 0.10 mm on 3-Tesla MRI and/or a loss in joint-space width [JSW] of (cid:21) 0.20 mm. Associations were assessed using multivariable statistical analyses. Results: Of 400 enrolled participants (mean age 58.6 years; 66.3% women), 374 (93.5%) completed follow-up; 154 (38.5%) lost <5%, 121 (30.2%) lost 5–10%, and 125 (31.2%) lost (cid:21) 10% of body weight. Of these, 93.5%, 71.1% and 21.6% progressed structurally, respectively (P<0.001). Greater weight loss was associated with significantly less cartilage and joint space loss (P<0.001). After adjustment, the odds of structural progression were markedly lower with 5–10% (adjusted odds ratio [aOR] 0.17; 95% CI 0.08–0.36) and (cid:21) 10% weight loss (aOR 0.02; 95% CI 0.01–0.04) versus <5%. Secondary outcomes also improved with greater weight loss (P<0.001). Conclusions: In adults with obesity and knee OA, greater 12-month weight loss was associated with markedly less structural progression, with a clear dose-response gradient and an apparent threshold near 10%. The clinical data presented here support weight-loss magnitude as a clinically-relevant treatment target.