Effects of L-carnitine on dialysis-related hypotension and muscle cramps: a meta-analysis.

BACKGROUND

L-Carnitine is an endogenous compound thought to be helpful in treating patients with dialysis-related hypotension and muscle cramps; however, sufficient evidence for these indications is lacking.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & POPULATION: Adult patients with end-stage renal disease receiving long-term hemodialysis.

SELECTION CRITERIA FOR STUDIES

All published English-language reports of randomized placebo-controlled trials of L-carnitine supplementation in adult long-term hemodialysis patients.

INTERVENTION

Supplemental L-carnitine (or placebo) for at least 8 weeks.

OUTCOME

Random-effects pooled odds ratio for intradialytic cramping or hypotension in L-carnitine-treated participants.

RESULTS

Of 317 potentially relevant articles, 7 (total enrollment of 193 patients) met criteria for inclusion. Four articles reported results for both hypotension and cramps, 1 had results for only hypotension, and 2 reported results for only cramps. Using data from all 6 relevant trials, the pooled odds ratio for cramping after L-carnitine supplementation was 0.30 (95% confidence interval, 0.09 to 1.00; P = 0.05). Analysis of the 5 studies examining the response of intradialytic hypotension to l-carnitine supplementation yielded a pooled odds ratio of 0.28 (95% confidence interval, 0.04 to 2.23; P = 0.2).

LIMITATIONS

The small number of available studies yielded limited statistical power. In addition, there was considerable interstudy heterogeneity.

CONCLUSIONS

Although suggestive in the case of muscle cramping, the available evidence does not confirm a beneficial effect of L-carnitine supplementation on dialysis-related muscle cramping or intradialytic hypotension. Additional study in the form of large rigorous randomized trials is needed in both cases.