Creatine for treating muscle disorders.
Level 1 - systematic review of randomized trials
Cochrane systematic review and meta-analysis of randomized controlled trials
PubMed 23740606 · doi:10.1002/14651858.CD004760.pub4
What was done
This Cochrane systematic review update searched CENTRAL, MEDLINE, EMBASE, and the Cochrane Neuromuscular Disease Group register up to September 2012 for randomized and quasi-randomized controlled trials comparing creatine to placebo in patients with hereditary muscle diseases or idiopathic inflammatory myopathies. Two independent authors assessed trial quality and extracted data.
What was found
A total of 14 trials (364 randomized participants) met the selection criteria. In muscular dystrophies (6 trials, n = 192), creatine produced a statistically significant increase in muscle strength compared to placebo (mean difference 8.47%, 95% CI 3.55 to 13.38). Four trials (n = 115) found significantly more participants reported feeling better on creatine (risk ratio 4.51, 95% CI 2.33 to 8.74). In idiopathic inflammatory myopathies (1 trial, n = 37), functional performance improved significantly. In metabolic myopathies (3 crossover trials, n = 33), meta-analysis showed no significant difference in muscle strength. In McArdle disease (1 trial), high-dose creatine significantly worsened activities of daily living (mean difference 0.54 on a 1–10 scale, 95% CI 0.14 to 0.93) and increased muscle pain. No trials reported clinically relevant adverse events.
Why it matters
Creatine is an effective, well-tolerated short- to medium-term option for improving strength and functional well-being in muscular dystrophies and inflammatory myopathies, but it should not be used in McArdle disease where high doses can exacerbate symptoms.
Limits
The total patient population was small across individual disease categories (e.g., only 33 patients across 3 metabolic myopathy trials, and 37 patients in a single inflammatory myopathy trial). Follow-up was limited to short- and medium-term treatment, leaving long-term outcomes unmeasured. One included trial was at high risk of selection, performance, and detection bias.
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