Association of Low Serum l-Carnitine Levels with Peripheral Arterial Stiffness in Patients Who Undergo Kidney Transplantation.

l-carnitine is an important co-factor in fatty-acid metabolism, and its deficiency is associated with insulin resistance, which is independently associated with arterial stiffness. This study evaluated the relationship between serum l-carnitine level and peripheral arterial stiffness (PAS) in kidney transplantation (KT). Fasting blood samples were collected from 65 patients who underwent KT. We measured the brachial-ankle pulse wave velocity, and 36 patients (55.4%) had PAS. Patients with PAS had a significantly higher percentage of diabetes (p = 0.001), hypertension (p = 0.033), and metabolic syndrome (p = 0.044); higher waist circumference (p = 0.010), systolic blood pressure (p = 0.002), serum triglyceride level (p = 0.040), insulin level (p = 0.002), and homeostasis model assessment of insulin resistance (p = 0.002); lower high-density lipoprotein cholesterol (p = 0.036) and serum l-carnitine levels (p < 0.001); older age (p = 0.041); and a longer KT duration (p = 0.025) than those without PAS. Statistical analysis revealed an independent association between PAS in KT and KT duration (95% confidence interval (CI): 1.003-1.054, p = 0.029) and serum l-carnitine levels (95% CI: 0.842-0.998, p = 0.044). The area under the receiver operating characteristic curve indicated that the diagnostic power of l-carnitine to predict PAS was 0.789 (95% CI: 0.670-0.881, p < 0.001). Serum-free l-carnitine level is negatively associated with PAS in patients who undergo KT.