Creatine supplementation for patients with COPD receiving pulmonary rehabilitation: A systematic review and meta-analysis

Background and objective: Creatine improves muscle strength in exercising healthy individuals, and in patients with neuromuscular disease and heart failure. The aim of this study was to assess whether creatine supplementation improves pulmonary rehabilitation (PR) outcomes in patients with COPD. Methods: A systematic review and meta-analysis was performed of randomized controlled trials published between January 1966 and February 2009 that evaluated the effect of creatine compared with placebo on exercise capacity, muscle strength and health-related quality of life (HR-QoL) in patients undergoing PR for COPD. The pooled estimates were expressed as mean differences (MD) or standardized mean differences (SMD). Results: Four randomized controlled trials that included 151 patients were identified. There was no effect of creatine supplementation on exercise capacity (SMD -0.01, 95% CI: -0.42 to 0.22, n = 151). Creatine supplementation did not improve lower extremity muscle strength (SMD 0.03, 95% CI: -0.55 to 0.61, n = 140) or upper limb muscular strength (SMD 0.02, 95% CI: -0.33 to 0.38, n = 128) compared with placebo. Two studies (n = 48) assessed quality of life using the St. George's Respiratory Disease Questionnaire. There were no differences in HR-QoL according to domain or total scores. Overall, creatine appeared to be safe and was well tolerated. Quality assessment of the studies showed important limitations. Conclusions: Creatine supplementation does not improve exercise capacity, muscle strength or HR-QoL in patients with COPD receiving PR. However, important limitations were identified in the quality of the available evidence, suggesting that further research is required in this area.