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Student number: u3119466

Paper reviewed:Exercise and Dietary Weight Loss in Overweight and Obese Older Adults With Knee Osteoarthritis Stephen P. Messier, Richard F. Loeser, Gary D. Miller, Timothy M. Morgan, W. Jack Rejeski, Mary Ann Sevick, Walter H. Ettinger Jr, Marco Pahor and Jeff D. Williamson

Background:
Arthritis is a leading cause of physical disability in older adults, distressing more than 70 million Americans. The joint damage and chronic pain from osteoarthritis, leads to muscle atrophy, poor balance and physical disability.

Other clinical exercise trials have shown significant improvements in function and pain in older adults with knee osteoarthritis. There is also evidence that shows obesity is strongly associated with knee osteoarthritis and that weight loss can aid and prevent the onset of this deteriorating disease. The American College of Rheumatology and the European League against Rheumatism recommend weight loss and exercise for obese patients with knee osteoarthritis.

Where is the research from?
This study was performed at the Claude D. Pepper Older Americans Independence Centre of Wake Forest University, with the approval of the university. ADAPT was a single blind, randomized, and controlled clinical trial of older overweight and obese adults with knee osteoarthritis. The study was designed so that it would compare the effects of assignment to 4 distinct 18-month interventions being exercise only, diet only, diet and exercise, and usual care healthy lifestyle as a control group.

What did the research involve?
To be deemed eligible for the study the criteria was as follows 1) Age 60 years and above 2) Calculated body mass index of 28 kg/m2 and above 3) Knee pain on most days of the month 4) Sedentary activity pattern with 20 minutes of formal exercise once weekly for the past 6 months 5) Self-reported difficulty in at least one of the following activities ascribed to knee pain, walking one quarter of a mile, climbing stairs, bending, stooping, kneeling, shopping, house cleaning or other self-care activities, getting in and out of bed, standing up from a chair, lifting and carrying groceries, or getting in and out of the bathtub 6) radiographic evidence of grade I–III tibiofemoral or patellofemoral osteoarthritis 7) Willingness to undergo testing and intervention procedures.

Each participant was given a program at random, either the exercise only, diet only or the diet and exercise program. The diet and exercise consisted of an aerobic phase, a resistance-training phase, a second aerobic phase, and a cool down phase. The goal of the dietary intervention was to produce and maintain an average weight loss of 5% throughout the intervention.

What kind of research was this?
During both trials the isometric strength of 8 muscle groups located in the upper and lower extremities were evaluated by measuring strength output, range of motion and general functionality. Functional measurements including gait velocity were utilized to investigate the impacts of the training on general mobility.

The differences in diagnosis amongst the participants is an advantage of this study. Comparing the subjects allowed for conclusions to be indicated. Having two different groups represented, along with different symptom severity, provided an awareness as to how this treatment could benefit everyone.

Basic results?
Total number of people pre-screened by phone during an 18 month period was 2,209. Of these, 72% were ineligible, and 13% declined, leaving 316 persons who were randomized into 1 of the groups. Of the 316 participants, (80%) saw the study through.

Maintenance of participants was not considerably different between the groups. In the diet only, 72% adherence, for exercise only, 60%, and for diet and exercise, 64%. The healthy lifestyle group, adherence was 77% for the first 3 months and 73% for the remaining months. There was no considerable difference in adherence between the 3 diet and/or exercise groups. After the first 4 months of facility-based exercise, 64% of the subjects in the groups with exercise chose to remain in the same program, 24% opted for the program based at home, and 12% of the subjects chose a mixed facility/home program.

The main outcome of the study was self-reported physical function. Using baseline function and sex as covariates, revealed that participants in the diet and exercise program significantly increased their physical function. The secondary outcome of weight loss showed both intervention groups involving diet lost significantly more weight than the healthy lifestyle group. The Third outcome being pain showed the diet plus exercise group made significant increases in self-reported pain compared to the healthy lifestyle group.

How did the researchers interpret the results?
Results of previous studies suggest that the combination of dietary weight loss and exercise is effective in improving self-reported physical function compared with exercise only or diet only, and pain therapy. This analysis indicated that all of the intervention groups and the healthy lifestyle group seemed to have increases in function. When diet was combined with exercise, subjects realized the greatest benefit in function. Remarkably, the three intervention groups improved in the first 6 months, and then maintained this improvement until the total 18 months. Hence, it suggests that the combination of diet plus exercise yields better and clinically relevant increases in self-reported physical function compared with either diet or exercise alone.

Conclusions and implications


Older adults with knee Osteoarthritis are disinclined to exercise in fear of worsening their pain. Increases in the diet and exercise groups was dependent on the type of outcome measure. Specifically, the diet-only group performed better than the exercise only group on self-reported measures, and the reverse for mobility. It seems logical, that combining the two programs would lead to consistently superior results on both self-reported and mobility measures. For years, physicians have recommended that overweight patients with knee osteoarthritis exercise and lose weight, and this has been recommended in the ACR guidelines for the management of knee osteoarthritis. This study is the first large, randomized, controlled clinical study to validate the relative and combined contributions of exercise and diet on weight loss, function, and pain in patients with knee osteoarthritis.