FREDERIKSBERG, Denmark—Losing just 5% of total body weight within a 20-week period  — or 0.25% per week -- should be enough for overweight or obese patients with knee osteoarthritis (OA) to feel and function better, according to the pooled results of a new meta-analysis published in the Annals of Rheumatic Diseases.¹

"Professionals treating knee OA should bear a possible weight reduction in mind whenever a patient is significantly overweight," conclude researchers led by Robin Christensen of Frederiksberg Hospital in Frederiksberg, Denmark. "The patients ought to be encouraged to reduce their body weight, at least by 5% within a 20-week period, to experience symptomatic relief."

Researchers identified 35 trials through a literature search, but only four randomized controlled trials (including five intervention/control groups) met the study's inclusion criteria. The new study comprised data for 454 patients. The pooled effect size for pain and physical disability were 0.20 and 0.23 at a weight reduction of 6.1 kg (4.7 to 7.6 kg). While the predictability of weight loss's effect on pain was questionable, weight loss predicted knee OA patients' reduction in self-reported disability, the study showed.  Disability could be significantly improved when weight was reduced over 5.1%, or at the rate of >0.24% reduction per week, according to a meta-regression analysis.

"This study presents evidence-based estimates from a meta-analysis to support the use of weight-loss regimens in the clinical management of OA in clinical rheumatology," the researchers conclude. 

Kick weight loss up a notch

"Weight loss is very effective and it's best to combine it with exercise," Stephen P. Messier, PhD,  professor of biomechanics at Wake Forest University in Winston-Salem, North Carolina, told CIAOMed. "For OA patients, in general, exercise, including walking and weight training, should be incorporated with modest weight loss if the patient is overweight or obese."

Dr. Messier and colleagues are now beginning a 5-year study, called IDEA (Intensive Diet and Exercise for Arthritis), to look at the effects of a 10% to 15% weight loss in knee OA patients. "We feel that the 5% weight loss doesn't slow the progression of disease; it does improve pain and function, but it doesn't slow the progression of  OA. We are hoping that a 10% to 15 % weight loss does trigger enough of a change on the load on the knee and decrease inflammation, so that we can slow progression of disease, and OA patients will have more years of independent living and a better quality of life," Dr. Messier commented.

Several of Dr. Messier's studies were included in the new meta-analysis.

Reference

1. Christensen R, Bartels EM, Astrup A, et al. Effect of weight reduction in obese patients diagnosed with knee osteoarthritis: a systematic review and meta-analysis. Ann Rheum Dis. 2007;66:433-439.