Moderate weight loss improve functioning and pain in knee OA

[Guest guest]

Rheumawire

May 27, 2004

At last, proof that exercise plus moderate weight loss improve

functioning and pain in knee OA

New York, NY - Although doctors have been recommending for many years

that overweight patients with knee osteoarthritis (OA) exercise and lose

weight, it is only now that the efficacy of this advice has been proven

in a large controlled trial [1].

The Arthritis, Diet, and Activity Promotion Trial (ADAPT) found that

participants in an 18-month program of exercise and a calorie-restricted

diet showed a 24% improvement in physical function and a 30.3% decrease

in knee pain. These improvements were far superior to those seen in

patients relegated to exercise only or to diet only as well as those

seen in the control group. The results are reported in the May 2004

issue of Arthritis & Rheumatism by Dr Messier (Wake-Forest

University, Winston-Salem, NC) and colleagues.

" There have been several epidemiological studies that have shown that

obesity and subsequent weight loss are important in knee OA, " Messier

tells rheumawire. " We thought that looking at a combination of exercise

and weight loss would give people an additional benefit compared with

exercise alone and, indeed, it did. "

" It sure does work, " he continues. " We got our greatest benefits after 6

months, and the diet-plus-exercise group maintained these benefits for

an additional year, with no regression toward baseline values. "

" Based on our study and from a nonpharmacological standpoint, if a

patient is overweight and obese, combining exercise with weight loss

should be the standard, " Messier says.

An accompanying editorial [2] by Dr Fransen (Institute for

International Health, New South Wales, Australia) says these results are

" important for clinicians and patients. "

This is the first large, randomized clinical trial assessing the

symptomatic benefit of a facility-based, dietary weight-loss program

with or without the addition of a supervised exercise classes for

individuals with knee OA, she points out. Another factor that makes this

trial unique is that the researchers recruited only individuals who

could be classified as markedly overweight or obese. " Because the

proportion of overweight patients with knee OA is likely to increase

with the rapidly growing prevalence of obesity in most parts of the

world, the results of ADAPT should be of great interest to most

clinicians, " Fransen writes.

ADAPT was conducted in 316 community-dwelling overweight and obese

adults (with a body mass index >28kg/m2) with knee pain and radiographic

evidence of knee OA and self-reported disability. They were randomized

into 4 groups: healthy lifestyle (control), diet only, exercise only, or

diet plus exercise.

The exercise group participated in aerobic and resistance activities for

1 hour 3 times a week, the diet group attended regular meetings on how

to change their eating habits and reduce daily calories, and the

combination group did both. By contrast, the control group met monthly

for 1 hour for the first 3 months and received health education on OA,

obesity, and exercise.

Compared with the 24% improvement among patients in the combination

group, there was an 18% improvement in physical function in the

diet-only group. Moreover, there was a nonsignificant 12% improvement in

the exercise-only group and a 13% improvement among participants in the

control group.

The primary outcome measure was based on self-reported physical function

by the Western Ontario and McMaster Universities Osteoarthritis Index

(WOMAC). The secondary outcome was weight loss. Researchers also used

WOMAC to assess pain, and participants completed 2 performance-based

tasks including distance walked in 6 minutes and a timed stair-climbing

task.

In the diet-plus-exercise group, significant improvements were seen in

the 2 performance tasks and knee pain relative to the control group. The

exercise-only group showed an improvement in the 6-minute walking task,

while the diet-only group was not different from the control group in

any measures. As far as weight loss, the diet group lost 4.9% of body

weight and the exercise-plus-diet group shed 5.7%, both of which were

greater than the 1.2% weight loss achieved among people in the control

group. Difference in joint-space width assessed by knee radiograph did

not differ among the groups

The ultimate goal of such an intervention is to slow the decline in

physical function that leads to disability in OA patients, and " we

succeeded in this study, " Messier tells rheumawire. Patients will derive

more years of independent living and better quality of life, he says.

" Considering the side effects that often limit the use of OA drug

therapy and the possible ineffectiveness of surgical interventions in

cases of mild to moderate knee OA, our results give strong support to

the combination of exercise and weight loss as a cornerstone for the

treatment of overweight and obese patients with OA, " Messier concludes.

Adherence to exercise and diet can be an issue, Messier comments. " It

seems to us that to be successful, there needs to be constant, frequent

contact, " he says. " We had weekly and biweekly contact depending on the

intervention group, but to give them short intensive intervention and

then let them go is less successful. "

In general, " the more successful weight-loss programs have more

attention, whether by phone, mail, or face to face, " he says. " There

needs to be a good regimen of frequent contact. "

One issue that remains to be addressed is the question of whether more

is even better. ADAPT looked at modest weight loss, but is more weight

loss better and just as safe, Messier asks. " You have to be careful in

older adults with weight loss, because of bone density and muscle

wasting, " he cautions.

To that end, Messier and his team had already conducted a pilot study

looking at a weight loss of 10% to 12% in knee OA patients. " We know we

can get this type of weight loss using partial meal replacements such as

Slimfast®, so now we can compare intensive weight loss, the weight loss

in ADAPT (5%), and compare that with a group who maintains weight, " he

says.

The editorial concurs and also highlights other questions that remain.

" Further research is now clearly needed to explore whether more

ambitious weight-loss targets, differing the exercise-class content, or

increasing exercise intensity for the population will result in larger

symptomatic benefits. "

Mann

Sources

1. Messier SP, Loeser RF, GD, et al. Exercise and dietary weight

loss in overweight and obese older adults with knee osteoarthritis: the

Arthritis, Diet, and Activity Promotion Trial. Arthritis Rheum 2004 May;

50(5):1501-10.

2. Fransen M. Dietary weight loss and exercise for obese adults with

knee osteoarthritis: modest weight loss targets, mild exercise, modest

effects. Arthritis Rheum 2004 May; 50(5):1366-9.

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org