Association of serum L-carnitine levels with aortic stiffness in kidney transplant recipients: A cross-sectional study

A BSTRACT L-carnitine supports mitochondrial fatty-acid transport. L-carnitine deficiency has been linked to insulin resistance and vascular dysfunction. Aortic stiffness, a marker of vascular aging, is recognized as an independent predictor of cardiovascular events and mortality. We examined whether serum L-carnitine is associated with aortic stiffness in kidney transplant (KT) recipients. We performed a cross-sectional study of 98 KT recipients. Aortic stiffness was defined as carotid–femoral pulse wave velocity (cfPWV) >10 m/s measured by the SphygmoCor system. Serum L-carnitine concentrations were quantified via liquid chromatography-tandem mass spectrometry. Among 98 recipients, 28 (28.6%) had aortic stiffness. Compared with controls, they were older ( P = 0.011), more often had diabetes ( P = 0.031), and had higher systolic blood pressure ( P = 0.010) and fasting glucose levels ( P = 0.001), as well as lower L-carnitine levels ( P < 0.001). In multivariable logistic regression, lower L-carnitine (odds ratio [OR]: 0.940; 95% CI: 0.903–0.977, P = 0.002) and older age (OR: 1.062; 95% CI: 1.000–1.127, P = 0.049) were independently associated with aortic stiffness. Stepwise linear regression showed an inverse association between log-transformed L-carnitine levels and cfPWV values (β = –0.321, adjusted R ² change = 0.097, P < 0.001). Receiver operating characteristic analysis indicated moderate discrimination (area under the curve: 0.758, 95% CI: 0.665–0.862, P < 0.001). Lower serum L-carnitine levels are associated with aortic stiffness in KT recipients. These findings are hypothesis-generating and indicate that prospective or interventional studies are needed to determine whether modifying L-carnitine status can improve vascular stiffness in this population.