Obesity is a worldwide health issue and a major and modifiable risk factor for many patients with knee osteoarthritis (OA). For overweight and obese adults, the National Institutes of Health (NIH) recommend patients set an initial goal of losing 10% of their baseline weight. However, the benefits beyond what has been shown with 10% weight loss in patients with knee OA are unknown.
In their latest research, Stephen P. Messier, PhD, Wake Forest University, Winston-Salem, N.C., and colleagues conducted a secondary analysis of the weight loss groups in the Intensive Diet and Exercise for Arthritis (IDEA) trial. The goal of the analysis was to determine the effect of greater weight loss on the clinical and mechanistic outcomes at the 18-month follow up.
The 240 study participants were overweight and obese adults over 55 years old with pain and radiographic knee OA. Participants were assigned to one of four groups according to weight loss achieved: less than 5%, 5–10%, 10–20% and more than 20%. The results of the study were published in the November 2018 issue of Arthritis Care & Research.
“Long-term weight loss of 10–19.9% of baseline body weight has substantial clinical and mechanistic benefits compared with less weight loss,” write the authors. “The value of an additional 10% weight loss includes significantly improved physical health-related quality of life and a clinically important reduction of pain and improvement in function.”
Patients who experienced moderate to intensive weight loss (less than 10% of baseline) did have positive outcomes for clinical and mechanistic measures. However, 13% of patients safely lost more than 20% of their baseline weight. At the 18-month follow up, these patients experienced 25% less pain and significantly better function compared with the 10–20% group.
Although the study supports the NIH recommendation of 10% initial weight loss from baseline, the authors note this clinically important 25% mean reduction in pain and improvement in function when progressing from 10 to 20% weight loss suggests that greater weight loss may have additional clinical value. “The added benefit of substantially greater weight loss, achieved safely and without pharmacologic or surgical intervention, is an intriguing possibility that warrants further study,” write the authors.
The authors conclude by recommending the standard of care for older overweight and obese adults with knee OA include—at minimum—a 10% weight loss using the techniques developed in previous successful weight loss trials, such as IDEA and Osteoarthritis Healthy Weight for Life.