LEP and chronic kidney disease: Several biomarkers have been correlated with the prevalence and severity of CKD, including metabolic syndrome markers (e.g., adiponectin and leptin) [6,7], inflammatory markers (e.g., tumor necrosis factor-alpha (TNF-α)) [8], mineral metabolism markers (e.g., total vitamin D) [9], and glomerular filtration markers (e.g., cystatin C) [5,10].