Carnitine deficiency is associated with decreased exercise activity in hemodialysis patients

Abstract

Background and aimCarnitine deficiency is common and associated with muscle atrophy in hemodialysis (HD) patients. We investigated whether carnitine levels could be an independent predictor for exercise capacity in these patients.MethodA total of 37 patients (mean age, 55.9 ± 13.4 years) who underwent HD three times a week were enrolled in this study. Carnitine fraction levels were measured by the enzyme cycling method. Univariate and multiple stepwise regression analyses were performed to determine the correlation between free carnitine levels and the value of exercise capacity examined by the time-up-and-go test (TUG), knee extension strength, functional reach test (FRT), and 10-m walk test, and thigh and calf circumferences as markers of muscle mass.ResultsSerum free carnitine levels were significantly decreased in HD patients. Free carnitine levels were associated with TUG (inversely; r2 = 0.120, P = 0.035), knee extension strength (r2 = 0.129, P = 0.029), FRT (r2 = 0.246, P = 0.002), and the 10-m walk test (inversely; r2 = 0.149, P = 0.018). Multiple stepwise regression analysis revealed that free carnitine was an independent predictor for FRT (β = 0.369, P < 0.001). There was no correlation between free carnitine levels and thigh and calf circumferences.ConclusionLow serum free carnitine levels were associated with decreased exercise capacity in HD patients, suggesting that carnitine deficiency may be a promising therapeutic target for HD-associated muscle weakness in HD patients. This study was retrospectively registered.