KL and chronic kidney disease: In our subjects, the prevalence of the patients treated with RAS inhibitors trended towards greater values with advancing stages of CKD (data not shown), thereby the distribution of CKD stages were not comparable between the subjects with RAS treatment and those without RAS treatment, and this fact preclude us to precisely evaluate the impact of such agents on the amount of urinary excreted Klotho and the serum levels of soluble Klotho.