Community-deliverable exercise and depression in adults with arthritis: Confirmatory evidence of a meta-analysis using the IVhet model.

OBJECTIVE: Using the traditional random-effects model, a recently reported standardized effect size (g) reduction of -0.42 (95% CI, -0.58 to -0.27) was observed in depressive symptoms as a result of community-deliverable exercise in adults with arthritis and other rheumatic diseases. However, a recently proposed alternative model (IVhet) has been shown to have superior coverage probability to the random-effects model. The purpose of this brief report was to compare these previous random-effects results with the IVhet model.

METHODS: Based on a previous meta-analysis of 35 g's representing 2449 participants, results for depressive symptoms were pooled using the IVhet model. Influence analysis, number needed-to-treat, percentile improvement, and gross estimates of the number of inactive adults with arthritis who could benefit from exercise were also calculated.

RESULTS: The IVhet model yielded statistically significant reductions in depressive symptoms (g = -0.30, 95% CI, -0.49 to -0.11), a difference that was -0.12 (28.7%) smaller than the random-effects model. With each study deleted from the model once, results remained statistically significant, ranging from -0.28 to -0.34. The percentile improvement, number needed-to-treat, and estimated number of people with arthritis in the United States who could improve their depressive symptoms by participating in a regular exercise program were, respectively, 11.8% (95% CI, 4.5% to 18.8%), 8 (95% CI, 5 to 23), and 2.7 million (95% CI, 1.0 to 4.4 million).

CONCLUSIONS: These findings provide more conservative and accurate evidence that community-deliverable exercise improves depressive symptoms in adults with arthritis and other rheumatic diseases. Future meta-analyses may want to consider using the IVhet versus traditional random-effects model.