To use the minimal important difference (MID) versus the standardized mean difference (SMD) approach in order to provide more robust and clinically relevant information regarding the association between land-based aerobic exercise and changes in self-reported fatigue among adults with rheumatoid arthritis (RA).
Data from a previous meta-analysis of 5 randomized controlled trials that represented up to 298 participants per study were utilized to calculate 9 effect sizes, using the MID approach. Data used to obtain the MID were derived from previously reported anchor-based values specific to each fatigue instrument in adults with RA. Results were pooled using a random-effects model.
Aerobic exercise resulted in statistically significant reductions in self-reported fatigue (MID effect size -0.34 [95% confidence interval (95% CI) -0.58, -0.10]; P = 0.006). Results were similar when effect sizes were collapsed so that only 1 effect size represented each study (MID effect size -0.39 [95% CI -0.76, -0.03]; P = 0.04).
Land-based aerobic exercise is associated with statistically significant reductions in fatigue; however, based on previous cut points, it may be unlikely that a substantial number of participants with RA could obtain clinically relevant reductions in fatigue. Additional studies are needed, especially in those individuals with RA who have elevated levels of fatigue.