Small weight loss better than drugs for improving OA pain, stiffness, function

From Jointandbone.org, by Janis Kelly.

San Diego, CA - Losing even a small amount of weight can reduce pain, relieve stiffness, and improve daily functioning for patients with mild to moderate knee osteoarthritis (OA), in some cases more effectively than a coxib, Dr Susan J Bartlett (Johns Hopkins Medical Institutions, Baltimore, MD) reported at the 2005 ACR/ARHP Annual Scientific Meeting [1].
"A 15-pound weight loss reduced pain by 40%, improved function by 50%, and reduced stiffness by 48%. This compares favorably with the 28% improvement in function seen with drugs such as celecoxib or rofecoxib," said Bartlett.

The weight-loss intervention included classes on nutrition, physical activity, behavior, and attitudes. Bartlett described the exercise component as "lifestyle walking." Participants wore pedometers and gradually built up to 10 000 steps per day on most or all days of the week. The subjects in this study were 48 significantly overweight adults, all of whom met the American College of Rheumatology criteria for knee OA. At baseline, the mean weight of the 38 female subjects was 90.7 kg and of the 10 males was 101.9 kg. All had pain in one or both knees on more than half the days of each month and had difficulty with activities of daily living.
The investigators randomized the subjects to receive immediate or delayed intervention, and the delayed-intervention group served as controls.
The average weight lost by those in the immediate-intervention (weight-loss) group was 6.8 kg and 0.4 kg by those in the control group (p<0.001).>

Interestingly, in males, the improvements in stiffness, functioning, and total Western Ontario and McMaster University (WOMAC) Osteoarthritis Index score were highly associated with percentage of weight loss, and there were strong associations with both absolute fat loss and percentage of fat loss. In females, the improvements in pain, stiffness, functioning, and total WOMAC score were not significantly associated with absolute weight loss, percentage of weight loss, absolute fat loss, or percentage of fat loss.
Bartlett speculated that there may be psychological differences, such that even a small weight loss in women helped them feel better.
That major improvement in symptoms and function were associated with a relatively small weight loss suggests that the benefits might not be the result of a simple reduction in the weight burden on the OA knee. Increasing attention is being paid to the role of adipose tissues in inflammation. Dr Edward TH Yeh (University of Texas-Houston Health Science Center) and colleagues reported earlier this year that human fat cells produce the inflammatory mediator C-reactive protein (CRP) [2].
Bartlett tells rheumawire that her group has examined the relationship between weight loss, symptom improvement, and changes in inflammatory mediators such as CRP in patients with knee OA and will be reporting "intriguing data" in December.