ACR: Small Weight Loss Equals Big Gains In Osteoarthritis Quality Of Life

WASHINGTON, Nov. 14 -- For overweight patients with osteoarthritis of the knee, even a relatively minor weight loss can make a significant long-term difference in improving quality of life, a researcher said here.

A weight loss of about 15 pounds can be enough to lead to significant improvements in quality of life for moderately overweight or mildly obese patients, according to Steffany Haaz, a doctoral candidate at the Johns Hopkins School of Public Health.

And improvements in pain scores during and after losing the weight are sufficient motivation to keep the pounds off, Haaz said before presenting data from a 16-month study at the American College of Rheumatology meeting.

The take-home message is "doctors can now tell their patients they will feel better if you only lose a little weight," Haaz said. The message is less overwhelming for patients than being told they have to get down to a normal weight range.

Haaz noted that many medical societies recommend weight loss for overweight people with osteoarthritis, but the message is often transmitted as urging a fitness program that may be difficult or painful for patients.

She and colleagues tried a four-month behavioral intervention, in which patients attended weekly meetings to learn how to control calories, how to make their lives more physically active, and how to develop strategies for weight loss.

At the end of the four months, the patients had lost an average of 14.9 pounds, with significant improvements (at P<0.001) in physical function, physical limitations, and bodily pain, as measured by the standardized SF-36 test.

"The concern was that they would regain the weight and be as badly off as before," Haaz said.

But in a year of follow-up, that was not the case, she reported here. On average, the participants regained 5.5 pounds, but remained significantly below (P<0.05) their baseline weight, and the improvements on the SF-36 were maintained (P<0.01).

Neither the initial weight loss nor the magnitude of weight gain was associated with age, race, sex, education, baseline physical function, or initial weight.

"No matter how you were doing when you came in the door," Haaz said, "you had an equal shot at improvement with the program."

On the other hand, weight loss was significantly associated with improvements in bodily pain (P<0.05) and improvements in pain after the four-month intervention were significantly associated with keeping the weight off during follow-up (P<0.01).

Weight loss was also associated with improved blood pressure (r=0.34, P<0.05). In turn, low post-intervention blood pressure was the most robust predictor of keeping weight off during follow-up (r=0.46, P=0.01).

"The better they felt at the end of the program, the more likely they were to be able to keep the weight off," Haaz said. The relationship was "reciprocal," she said -- the less weight patients carried, the better they felt.

The study finding was "interesting," because obesity is an important risk factor for a poor outcome in cases of osteoarthritis of the knee, commented Robert Wortmann, M.D., of the University of Oklahoma College of Medicine in Tulsa, who was not part of the research team.

In essence, he said, the study demonstrated that losing less weight than it would take to get a normal body weight could lead to significant improvements in the symptoms of osteoarthritis of the knee.

"I was surprised by that a little bit," Dr. Wortmann said.