Effect of l-carnitine supplementation on clinical symptoms in women with osteoarthritis of the knee: A randomized, double-blind, placebo-controlled trial

Abstract

Introductionl-carnitine has been reported to be helpful in the treatment of osteoarthritis due to its prophylactic role in cartilage degradation. The aim of this study was to investigate the effect of l-carnitine supplementation on clinical symptoms of females with knee osteoarthritis (OA). MethodsIn this randomized double-blind placebo-controlled trial, 72 females with mild to moderate osteoarthritis of the knee were randomly assigned into two groups to receive 750mg/day l-carnitine (n=36) or placebo (n=36) for 8 weeks. Clinical symptoms were assessed using the WOMAC Osteoarthritis Index and 50% improvement was considered as the threshold for clinical significance. Data were analyzed by paired t-test, independent t-test, and analysis of covariance. ResultsSixty-nine patients completed the trial. l-carnitine supplementation led to significant reduction of 46.9%, 54.1%, 48.4% and 44.4% in the WOMAC total score and sub-scores of pain, stiffness and physical function, respectively (p<0.001); whilst in the placebo group, significant reductions were only observed in WOMAC total score and pain sub-score (p<0.05). Comparison of changes between two groups indicated significant differences in WOMAC total score and all sub-scores (p<0.05). These significant differences were also observed between the two groups after adjusting for baseline scores (p<0.001). The number needed to treat (95% CI) for patients who consumed l-carnitine for at least 50% reduction in WOMAC sub-scores of pain and stiffness were 3.3 (2.0, 14.90) and 2.1 (1.6, 4.13), respectively. DiscussionAlthough further studies are needed to confirm positive effects of l-carnitine on clinical symptoms in knee OA patients, it seems that l-carnitine may provide a new complementary approach for patients with osteoarthritis of the knee.