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.