Creatine for amyotrophic lateral sclerosis/motor neuron disease

Background Creatine, a naturally-occurring nitrogenous organic acid involved in adenosine triphosphate (ATP) production, has been shown to increase survival in mouse models of amyotrophic lateral sclerosis (ALS). Results from human trials, however, have been mixed. Given conflicting results regarding creatine's efficacy, we conducted a systematic review. Objectives To systematically examine creatine's efficacy in prolonging ALS survival and in slowing ALS disease progression. Search strategy We searched the Cochrane Neuromuscular Disease Group Trials Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library issue 4, 2009), MEDLINE and EMBASE in October 2009 for any trial involving creatine in the treatment of ALS. We also contacted experts in the field for any additional studies. Selection criteria Randomized trials of treatment with creatine or placebo in patients diagnosed with ALS. Our primary outcome was tracheostomy-free survival time; secondary outcomes were ALS progression as measured by changes in ALS functional rating revised scores (ALSFRS-R) and percent predicted forced vital capacity (FVC) over time. Data collection and analysis Two authors independently selected studies, assessed risk of bias and extracted data. We obtained and analyzed individual participant data from each study. Main results We included three trials involving 386 participants randomized to either creatine 5 to 10 g per day or placebo. Creatine was reportedly well-tolerated in all three included studies, with no evidence of renal failure or serious adverse events specifically attributable to creatine. Using a pooled log-rank statistical test, we found no statistical difference in survival between the placebo and creatine groups across all three studies (Chi(2) = 0.09, P = 0.76). In addition, we found no statistical difference in ALSFRS-R slopes between the two groups across all three studies using a pooled linear mixed-effects model (slope difference of + 0.03 ALSFRS-R/month in the creatine group; P = 0.76). Interestingly, there was a trend towards slightly worsened FVC slope in the creatine group (slope difference of -0.63 FVC/month in the creatine group) using a pooled linear mixed-effects model across the two studies which included FVC as an outcome, but this difference was not statistically significant (P = 0.054). Authors' conclusions In patients already diagnosed with clinically probable or definite amyotrophic lateral sclerosis (ALS), creatine at doses ranging from 5 to 10 g per day did not have a statistically significant effect on survival, ALS functional rating revised scores (ALSFRS-R) progression or percent predicted forced vital capacity (FVC) progression.