This is a cross-sectional case-control study. Between January 2013 and June 2015 children and adolescents aged 5-20 years, referred to the Pediatric Nephrology, Dialysis and Transplant Unit of Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico - Milan, Italy were enrolled. Subjects with CKD stages II-V under conservative treatment (CKD-CT), or undergoing hemodialysis treatment (CKD-HD), or being renal transplant recipients (RTx) were included in the study. Data about age, primary renal disease and concomitant medications were collected for each subject.