A pragmatic trial shows exercise and diet really can reduce pain for knee osteoarthritis patients outside laboratory conditions
Knee osteoarthritis pain levels can be improved in a real world setting with diet and exercise, according to research presented at ACR 2022 last week.
After 18 months, participants in the US community trial had a 32% reduction in pain, reduced waist circumference, increased the distance they were able to walk and had significantly better health related quality of life, the study showed.
“This study provides a blueprint for the implementation of a successful treatment for a pervasive public health problem in clinical and community settings,” the authors wrote.
Diet and exercise for the reduction of pain and improved function in adults with knee OA are recommended in clinical guidelines based on positive results in controlled conditions.
“For example, in our IDEA efficacy trial, the diet plus exercise group…reduced pain by 51% over an 18-month intervention period. However, these interventions have not been rigorously tested in community-based settings,” principal investigator Professor Stephen Messier told conference delegates.
The WE-CAN trial took place in community settings, in local facilities such as malls and gyms, and was delivered by local staff. It involved 823 people aged 50 or over with knee OA and a BMI of 27 kg/m2 or higher. Participants were randomised to an 18-month diet and exercise program in a community setting, or to the “attention control” group.
The first group did 30 minutes of walking and 20 minutes of weight training three times per week and were given low calorie recipes and a meal replacement shake option. The attention group had five one-hour face-to-face meetings over 18 months and were given alternate monthly information packages or phone sessions.
Knee pain levels were measured at the end of the period for all 658 who completed the trial, as well as function, health related quality of life (using the SF-36 scales) and distance walked in six minutes. There were 30 adverse events related to the exercise and diet group, none serious.
At the end of 18 months, both groups saw improvement in pain levels, though the diet and exercise group had better results with a WOMAC pain score of 4.9 versus 5.5 on a scale of 0-20 – a reduction of 32% and 24% respectively.
“This between group difference was modest and of uncertain clinical importance,” Professor Messier noted. But patients in the diet and exercise group were also 20% more likely to achieve a clinically meaningful reduction in pain of two or more points.
The diet and exercise group lost around 9cm in waist circumference compared to 4cm in the other group and an average of 8kg each, compared to 2kg in the other group.
“There was a significant association between weight change and change in … pain for the diet plus exercise group that was not apparent in the control group,” Professor Messier said.
The function score for the diet and exercise group was 16.4, a 36% improvement, versus 19.7 for the control group, an improvement of 22%, on a scale of 0-68 where lower is better.
The diet and exercise group increased the distance they were able to walk in six minutes by 41 metres from baseline to 416m, while the other group walked 376m – the same as at baseline.
The diet and exercise group had a higher level of physical activity at the end of 18 months than the control group, but there was no real difference in pain medication use and the number of depressive symptoms did not significantly differ.
Health related quality of life improved by 20% for the diet and exercise group, and only 6% for the control group.
Asked whether he thought patients would revert to previous dietary habits and regain the lost weight, Professor Messier pointed out that the diet was not very restrictive – a minimum daily intake of 1100 calories for women and 1200 for men.
Furthermore, in an eight year follow up of the IDEA trial, patients maintained a 6% weight loss, starting from 10% at the end of the study.
“This was after three and a half years of no contact after a five-year trial, so that’s pretty good,” Professor Messier concluded.
