November 7, 2011 (Chicago, Illinois) — Intensive diet and exercise can slash the amount of pain in older adults with osteoarthritis of the knees and improve function and walking speed, according to a study from researchers at Wake Forest University in Winston-Salem, North Carolina.
The 18-month Intensive Diet and Exercise for Arthritis (IDEA) trial was designed to evaluate the impact of intensive weight loss with or without exercise on disease progression. The results presented here at the American College of Rheumatology 2011 Annual Meeting are the first from the trial, and focus on pain and function only.
Investigators randomized 454 overweight and obese individuals (72% women), with a mean body mass index of 33.6 kg/m2 and an average age of 65.6 years, to 1 of 3 groups: intensive diet designed to achieve weight loss of 10% or more; moderate exercise only (two 15-minute walks and 20 minutes of weight training 3 times a week); or both. Participants met weekly for the first 6 months, and biweekly thereafter. Eighty-eight percent of participants completed the 18-month study.
At the end of the study, participants in the diet-only group lost an average of 9.5% of their baseline weight, and those in the exercise-only group lost an average of 2.2%. The combined diet/exercise group, however, lost an average of 11.4%. None of the participants regressed to baseline levels, even after 18 months.
Although all groups reported less pain at 6 months, the difference between groups was not significant. However, at 18 months, the combined diet/exercise group experienced a 51% reduction in pain, compared with 27% and 28% in the diet-only and exercise-only groups, respectively (P < .0004), said lead author Stephen P. Messier, PhD, director of the J.B. Snow Biomechanics Laboratory at Wake Forest University. Forty percent of those in the combined group rated their pain at 0 or 1 at 18 months, he said, compared with 20% in the exercise-only and diet-only groups.
In addition, participants in the diet/exercise group improved their functional status by 47%, compared with 30% in the diet-only group and 26% in the exercise-only group. The combination group also increased walking speed by 12%, compared with 10% and 6% in the diet-only and exercise-only groups, respectively (P = .004).
"Clearly, our cohort has reversed the trend of declining mobility that is seen in older adults," Dr. Messier said. In fact, the combination group had a faster walking speed than healthy middle-aged women aged 40 to 62, and one equivalent to that of healthy middle-aged men, he said.
Eric L. Matteson, MD, chair of the Department of Rheumatology at the Mayo Clinic in Rochester, Minnesota, said that the most intriguing finding of the trial is that even patients who did not exercise experienced less pain.
"Both exercise and diet are a great way to improve pain and function," he said, "but what was really unique in this study was the observation that patients who lost weight had less pain associated with just the weight loss, not even any exercise." This could be the result of a lower load on the joints, he said, and might enable patients to postpone joint replacement surgery.
It is also possible that patients will be able to reduce the amount of pain medication they take if they lose weight, noted Dr. Messier, something his group hopes to show with additional analysis. "We are hoping from a public health standpoint that medication use goes down," he said, "and we expect it will."
The take-home message, he said, is that "clinicians can tell their patients that they will see marked improvement [in pain and function] in 6 months or less." The fact that significant differences did not appear between the groups until 18 months, however, "underscores the need for long-term studies to detect clinically and statistically meaningful results."
Dr. Messier and Dr. Matteson have disclosed no relevant financial relationships.
American College of Rheumatology (ACR) 2011 Annual Meeting: Abstract 722. Presented November 6, 2011.
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