Table 6.

Major studies involving Klotho and CKD progression in comparison with our study.

Study	Clinical setting	Results/observations
Pavik et al. [14]	87 adults with CKD (stages 1–5) and 21 controls.	Adjusted mean Klotho decrease was 3.2 pg/mL for each 1 mL/min decrease in eGFR
Kim et al. [15]	243 adults with CKD (stages 1–5)	1. Klotho levels independently predicted the composite outcome of doubling S Cr, ESKD, or death at a median follow-up of 30 months: adjusted HR per 10 pg/mL increase, 0.96; 95% CI: 0.94–0.98; p < 0.001. 2. If serum Klotho was ≤ 396.3 pg/mL, 35.2% reached the composite outcome versus 15.7% if > 396.3 pg/mL (p=0.03). 3. Klotho levels were lower at more advanced CKD stages (p value for trend <0.001) and correlated positively with eGFR and negatively with FGF23 and phosphate levels.
Seiler et al. [16]	312 adults with CKD (stages 2–4)	1. Klotho levels were significantly associated with age but not with eGFR. 2. Klotho levels were not associated with the composite outcome of death or KRT initiation at a mean follow-up of 2.2 years.
Drew et al. [17]	2496 adults within the Health ABC study (mean eGFR = 73 mL/min)	Klotho levels are independently associated with a 30% kidney function decline, with each doubling of Klotho associated with 20% decreased odds of a significant decline in kidney function over 10 years.
Our study	107 patients with CKD 2–4	1. Klotho levels were significantly higher in patients with higher GFR (> 60 mL/min/1.73 m2) compared with advanced stages of CKD (p value 0.02). 2. GFR fall was significantly higher in patients with lower Klotho levels (p value < 0.0001). 3. Percentage fall in Klotho was strongly correlated with percentage fall in GFR (Spearman's coefficient of rank correlation (rho): 0.845 (0.778–0.892), p < 0.0001. 4. At a given grade of proteinuria, GFR fall was higher in patients with lower Klotho levels (observation).