Intentional Weight Loss in Overweight and Obese Patients With Knee Osteoarthritis: Is More Better?

Objective To determine the dose response effect of weight loss on clinical and mechanistic outcomes in overweight and obese adults with knee osteoarthritis ( OA ). Methods This is a secondary analysis of the diet‐induced weight loss only (D) and diet‐induced weight loss plus exercise (D + E) groups in the Intensive Diet and Exercise for Arthritis randomized controlled clinical trial. The 240 participants were overweight and obese older community‐dwelling adults with pain and radiographic knee OA . Participants were assigned to 1 of 4 groups according to weight loss achieved over an 18‐month period: <5% (<5% group), 5–10% (≥5% group), 10–20% (≥10% group), and >20% (≥20% group). Results There were significant dose responses to weight loss for pain ( P = 0.01), function ( P = 0.0006), 6‐minute walk distance ( P < 0.0001), physical ( P = 0.0004) and mental ( P = 0.03) health‐related quality of life ( HRQ oL), knee joint compressive force ( P < 0.0001), and interleukin‐6 ( P = 0.002). Greater weight loss resulted in superior clinical and mechanstic outcomes, with the highest weight loss group (≥20% group) distinguishing itself on all measures compared with the <5% and ≥5% groups; the ≥20% group had 25% less pain and better function compared with the ≥10% group and significantly ( P = 0.006) better physical HRQ oL. Conclusion Long‐term weight loss of 10–19.9% of baseline body weight has substantial clinical and mechanistic benefits compared with less weight loss. The value of an additional 10% weight loss includes significantly improved physical HRQ oL and a clinically important reduction of pain and improvement in function.