Knee OA Pain Eased in Community-Based Weight-Loss Programs

PHILADELPHIA — What works in the clinic can also work in community settings: Patients who are overweight or obese with knee osteoarthritis can find relief from pain through diet and exercise programs conducted in recreation centers, local gyms, fitness centers, and other places close to home, according to investigators in a pragmatic randomized trial.

The Weight Loss and Exercise for Communities With Arthritis in North Carolina (WE-CAN) study was modeled after the successful Intensive Diet and Exercise for Arthritis trial, which showed that adults randomized to 18 months of either a diet and exercise program or diet alone had more weight loss and larger reductions in levels of the inflammatory cytokine interleukin-6 than patients randomized to exercise alone, and that diet alone was associated with greater reductions in knee compressive force than exercise alone.

That study was conducted by Stephen P. Messier, PhD, and colleagues at Wake Forest University, Winston-Salem, N.C.. As previously reported, the investigators also saw continued benefits for participants years after the original trial.

Dr Stephen Messier

With the WE-CAN trial, results of which were reported at the annual meeting of the American College of Rheumatology, Messier and colleagues took the intervention one step further, randomizing 823 community-dwelling adults who were overweight or obese (body mass index [BMI], ≥ 27 kg/m2) with knee OA to either an 18-month diet and exercise intervention or attention control group consisting of five 1-hour face-to-face meetings over 18 months, plus information packets and phone sessions during alternate months.

“Compared to the control group, diet plus exercise had a statistically significant but modest reduction in pain. Diet plus exercise was 20% more likely to attain a clinically important 2-point improvement in pain,” Messier said in an oral abstract session at ACR.

Real-world Setting

The primary goal of WE-CAN was to “determine whether adaptation of a diet and exercise academic center–based efficacy trial to community settings results in a statistically significant reduction in pain relative to an attention control.”

A total of 3,751 potential candidates were screened, and 823 were randomized and assigned to either a diet and exercise arm (414) or attention control arm (409). Of the patients randomized, 336 in the diet/exercise arm and 322 in the control arm attended the final 18-month follow-up visit.

The exercise component consisted of a 15-minute walking period, followed by a 20-minute weight-training period, and ending with a second 15-minute walking period. The diet goal was 10% or greater weight loss, aided by a distribution of low-calorie recipes to produce a reduced-calorie diet of the patient’s choice, with the option to include nutritional powder to make low-calories shakes as meal replacements, one or two per day for the first 6 months, with the option of one per day for the remaining months.

The pragmatic components included the use of established community facilities in both urban and rural counties in North Carolina, broad inclusion criteria, patient-centered outcomes, use of community-based staff to deliver the treatment, nonphysicians trained by study physicians to perform knee exams, and various means of communication, Messier said.

Participants in each arm were closely matched by demographic and clinical characteristics, with a mean age of 64.5 years in the diet/exercise group and 64.7 years in the attention control group, respective mean weight of 100.7 kg and 101.1 kg, and respective BMI of 36.7 and 36.9. Women comprised about 77% of participants in each group.

Endpoints Met

The trial met its primary endpoint of a significantly greater reduction in pain at 18 months in the diet and exercise group as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and scored on a scale of 0 (no pain) to 20 (worst pain).

In an analysis adjusted for sex, BMI, and baseline values, there was a 32% reduction in pain scores from baseline in the active intervention arm versus 24% in the control arm (P = .02).

In all, 60.2% of participants assigned to diet and exercise had a minimum reduction in pain scores of at least 2 points at 18 months, compared with 49.7% of participants assigned to the attention control group. This translated into a relative risk for achieving at least a 2-point improvement with diet and exercise was 1.20 (P = .01).

Among participants who remained in the study for the entire 18 months, there were significant improvements in the diet and exercise group compared with controls in the prespecified secondary endpoints of weight change (–8 kg vs. –2 kg), waist circumference, WOMAC function, 6-minute walk distance, and mean Short Form–36 health-related quality of life subscale (P < .001 for all comparisons).

Messier acknowledged that the diagnosis of knee OA was based only on ACR clinical criteria and was not confirmed with imaging. In addition, offering patients the option of free meal replacement limited the pragmatic nature of the intervention.

He also noted that the 24% reduction in pain seen in the control group suggests that interacting with patients can improve clinical outcomes.

“Tour de Force”

In the question-and-answer session following Messier’s presentation, David T. Felson, MD, a rheumatologist at Boston Medical Center, called in and said the study was “a tour de force” and congratulated Messier and colleagues on “a lovely study.”

Dr David Felson

Felson asked whether the investigators had conducted a mediation analysis to determine what proportion of the improvement was attributable to weight loss, and whether patients assigned to exercise were sticking with it throughout the study.

Messier replied that they had not yet done a mediation analysis but were continuing to examine the data. Regarding the exercise question, he noted that “the adherence was over 80% for 6 months and over 70% for the whole 18 months, so they did a really nice job.”

In an interview, session moderator Anne Davidson, MBBS, director of the rheumatology program at Northwell Health in Manhasset, N.Y., commented that the investigators managed to accomplish a very challenging task.

“In terms of recruitment of patients with engagement of community facilities and quality of data, I would say that, as far as an osteoarthritis study goes, this was really a tremendous effort on the part of all people involved,” she said.

She noted that, while the WE-CAN program may work in North Carolina, there may be barriers to implementing it elsewhere, such as large suburban areas where some patients experience food insecurity and others have difficulty with transportation and access to treatment facilities.

“The question here that remains is, as Felson asked, what is the contribution of weight loss and what is the contribution of exercise? Because if it’s just weight loss, we have a whole lot of new things coming to help with that,” she said.

The WE-CAN study was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Messier disclosed that GNC, a health food and nutrition chain, donated the meal replacements used by patients. Davidson reported no relevant conflicts of interest.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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