Creatine for treating muscle disorders

[Guest guest]

Cochrane Database Syst Rev. 2007 Jan 24;(1):CD004760.

Creatine for treating muscle disorders.

Kley R, Vorgerd M, Tarnopolsky M.

BACKGROUND: Progressive muscle weakness is a main symptom of most

hereditary muscle diseases. Creatine is a popular nutritional

supplement among athletes. It improves muscle performance in healthy

individuals and might be helpful for treating myopathies.

OBJECTIVES: To evaluate the efficacy of oral creatine

supplementation in muscle diseases.

SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease

Group Register in May 2004 for randomised trials using the search

term 'creatine'. We also searched the Cochrane Central Register of

Controlled Trials (The Cochrane Library, Issue 2, 2005) using the

same search term. We adapted this strategy to search MEDLINE

(PubMed, from January 1966 to September 2005) and EMBASE (from

January 1980 to May 2004). We reviewed the bibliographies of the

randomised trials identified, contacted the authors and known

experts in the field and approached pharmaceutical companies to

identify additional published or unpublished data.

SELECTION CRITERIA: Types of studies: randomised or quasi-randomised

controlled trials.Types of participants: people of all ages with

hereditary muscle disease.Types of intervention: any creatine

supplementation of at least 0.03 g/kg body weight/day.Primary

outcome measure: change in muscle strength measured by quantitative

muscle testing.Secondary outcome measures: change in muscle strength

measured by manual muscle testing, change in energy parameters

assessed by 31 phosphorous spectroscopy, change in muscle mass or a

surrogate for muscle mass, adverse events.

DATA COLLECTION AND ANALYSIS: Two authors independently applied the

selection criteria, assessed trial quality and extracted data. Some

missing data were obtained from investigators.

MAIN RESULTS: Twelve trials, including 266 participants, met the

selection criteria. One trial compared creatine and glutamine

treatment with placebo.In trials with 138 participants with muscular

dystrophies treated with creatine, there was a significant increase

in maximum voluntary contraction in the creatine group compared to

placebo, with a weighted mean difference of 8.47% (95% confidence

intervals 3.55 to 13.38). There was also an increase in lean body

mass during creatine treatment compared to placebo (weighted mean

difference 0.63 kg, 95% confidence intervals 0.02 to 1.25). No trial

reported any clinically relevant adverse event.In trials with 33

participants with metabolic myopathies treated with creatine, there

was no significant difference in maximum voluntary contraction

between the creatine and placebo group (weighted mean difference -

2.26%, confidence intervals -6.29 to 1.78). One trial reported a

significant increase in muscle pain during high-dose creatine

treatment (150 mg/kg body weight) in glycogen storage disease type

V.

AUTHORS' CONCLUSIONS: Evidence from randomised controlled trials

shows that short- and medium-term creatine treatment improves muscle

strength in people with muscular dystrophies, and is well-tolerated.

Evidence from randomised controlled trials does not show significant

improvement in muscle strength in metabolic myopathies. High-dose

creatine in glycogenosis type V increased muscle pain.