L-carnitine treatment in incident hemodialysis patients: the multicenter, randomized, double-blinded, placebo-controlled CARNIDIAL trial.

Background: L-carnitine levels decrease rapidly and steadily with duration of hemodialysis, and carnitine depletion can impair response to recombinant human erythropoietin (rHuEPO). The study hypothesis was that L-carnitine supplementation during the first year of hemodialysis would improve this response.

Design, Setting, Participants, & Measurements: From October 2006 through March 2010, this multicenter, randomized, double-blinded study assigned 92 incident hemodialysis patients to receive placebo or 1 g of intravenous L-carnitine after each dialysis session for 1 year. The primary outcome measure compared the groups for rHuEPO resistance index (EPO-RI), defined as weekly rHuEPO doses (IU/kg body weight divided by hemoglobin level) (g/dl).

Results: In the L-carnitine group, carnitine concentration increased from a mean ± SD of 79 ± 51 µmol/L to 258 ± 137 µmol/L; in the placebo group, it declined from 68 ± 25 µmol/L to 53 ± 24 µmol/L (interaction group × time, P<0.001). Carnitine deficiency affected about 30% of the patients in the placebo group during the study period. EPO-RI varied from 15.8 ± 11.3 to 9.5 ± 5.8 IU/kg per g/dl in the placebo group and from 20.6 ± 12.8 to 15.6 ± 15.9 IU/kg per g/dl in the L-carnitine group, for a mean variation of -3.94 ± 12.5 IU/kg per g/dl and -2.98 ± 15.5 IU/kg per g/dl, respectively (P=0.7). After adjustment for baseline characteristics, the EPO-RI course was similar in each group (difference between groups, P=0.10; interaction group × time, P=0.9).

Conclusions: Carnitine levels decrease by about 11% ± 33% during the first year of hemodialysis. Treatment of incident hemodialysis patients with L-carnitine does not improve their response to rHuEPO.