Exercise significantly reduced symptoms of depression in patients with fibromyalgia, osteoarthritis, rheumatoid arthritis, and systemic lupus erythematosus, according to the results of a recent study by George A. Kelley, PhD, Professor, and Kristi S. Kelley, MEd, Research Instructor, Department of Biostatistics, School of Public Health, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown (Kelley GA, Kelley KS. World J Rheumatol. 2016;6:23-29).
Using data from 29 randomized controlled trials examining the effects of aerobic exercise, strength training, or a combination of aerobic and strength-training exercise on depressive symptoms, the researchers sought to determine the value of using exercise to reduce depression in adults with arthritis and other rheumatic conditions. The 29 studies comprised 2449 patients between the ages of 18 and 85 years; 1470 engaged in exercise for an average of 19 weeks, and 979 were controls.
“The aim of the present investigation was to use a new approach, P-curve, to identify whether evidential value exists in support of exercise for reducing depression in adults with arthritis and other rheumatic conditions,” Dr Kelley and Ms Kelley explained. They used the Stouffer method to calculate Z-scores and examine selective-reporting bias, and, after adjusting for publication bias, calculated the average power of the tests included in P-curve.
According to the researchers, P-curve was used to determine whether selective reporting can be omitted as a reason for statistically significant results, in turn, providing greater assurance that the observed effect is true. They also noted that, compared with previously existing tests to address publication bias, P-curve has shown better performance.
Of the 29 studies included in their analysis, the researchers found that 15 (51.7%) had significant exercise and depression results (P <.05). None of the other results were deemed significant with regard to exercise increasing depression in adults with arthritis and other rheumatic conditions.
Results of the P-curve approach demonstrated a significant right-skew, suggesting that there is evidential value supporting exercise as a method for decreasing depression in patients with arthritis.
“The findings of the present investigation provide further confirmation regarding the positive effects of exercise on depressive symptoms in adults with arthritis and other rheumatic diseases,” Dr Kelley and Ms Kelley said. The investigators noted, however, that further research is necessary to identify patients who would benefit the most from physical activity.
“While a random-effects model that incorporates heterogeneity was used, such models do not explain potential sources of heterogeneity, little of which could be identified in the primary meta-analysis on which the current investigation was based. Given the former, it would appear plausible to suggest that a need exists for well-designed randomized controlled trials to determine what group of participants may benefit the most from exercise,” they concluded.