KL and chronic kidney disease: Only the amounts of urinary excreted soluble Klotho at CKD stages 4 and 5 were significantly lower compared with CKD stage 1 (Figure1A), while an inverse correlation between the amount of urinary excreted soluble Klotho and stages of CKD was confirmed (Spearman’s rho value = −0.462, p < 0.01).