Diet plus exercise confers significant benefits in knee osteoarthritis
medwireNews: Combining an intensive diet with exercise is more effective than exercise alone to improve joint pain and function in overweight people with knee osteoarthritis, research shows.
The Intensive Diet and Exercise for Arthritis (IDEA) trial found that the two-pronged approach was associated with less knee pain, better knee function, faster walking speed, and better physical health-related quality of life than exercise alone.
IDEA included 454 adults aged 55 years and older with a body mass index between 27 and 41 kg/m2, mild-to-moderate radiographic osteoarthritis in one or both knees, a sedentary lifestyle, and pain on most days.
They were randomly assigned to undertake one of three interventions: intensive weight loss, with a goal of losing 10-15% of baseline weight through calorie restriction (aiming for an energy-intake deficit of 800-1000 kcal/day); exercise for 1 hour three times per week for 18 months, comprising aerobic walking and strength training; or both weight loss and exercise.
All participants were assessed at baseline, 6 months, and 18 months. In all, 399 patients (88%) completed the study, with retention being comparable among the three groups and adherence to interventions ranging from 54% to 70%.
One of the study’s primary outcomes, peak knee joint compressive force, decreased most with diet alone (mean 265 N, a 10% improvement over baseline) and least with exercise alone (148 N, a 5% improvement), with diet plus exercise being intermediate (230 N, a 9% improvement).
The study’s other primary outcome was a marker of inflammation – plasma levels of interleukin-6; levels at 18 months were significantly higher in the exercise-alone group than in either diet-alone or diet plus exercise groups.
Further comparisons revealed that the diet plus exercise group had less pain relative to either the diet or exercise groups; the proportions of patients with little or no pain at 18 months were 38%, 20%, and 22%, respectively.
Many other outcomes - including function, mobility, weight loss, and health-related quality of life – were also improved more with diet plus exercise than with the single interventions.
Writing in JAMA, Stephen Messier (Wake Forest University, Winston-Salem, North Carolina, USA) and co-authors conclude: “The findings… suggest that intensive weight loss may have both anti-inflammatory and biomechanical benefits; when combining weight loss with exercise, patients can safely achieve a mean long-term weight loss of more than 10%, with an associated improvement in symptoms greater than with either intervention alone.”
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Joanna Lyford, Senior medwireNews Reporter