Bicarbonate Supplement Restores Urinary Klotho Excretion in Chronic Kidney Disease: A Pilot Study

Abstract

Objective: We tested the hypothesis that correcting acidosis may improve urinary Klotho excretion and serum α-Klotho. Design: This is a prospective, interventional, nonrandomized, open-label trial study. In this study setting, metabolic acidosis is commonly observed during chronic kidney disease (CKD). We reported a positive relationship between serum bicarbonate (Sbicar) and serum α-Klotho in these patients. Subjects: The study involved 20 patients with a known kidney disease referred for renal checkup. Inclusion criteria were age ≥ 18 years, CKD stage 3-5 non dialysis, Sbicar < 22 mmol/L, and not receiving bicarbonate supplementation. Intervention: Patients were then prescribed 1 g of oral sodium bicarbonate 3 times per day for 4 weeks. Main outcome measure: Patients were evaluated at two and 4 weeks by blood and urine measurements. Results: Mean serum Klotho was 615 ± 287 pg/mL, and mean serum Sbicar was 19.3 ± 1.7 mmol/L at baseline. Sbicar increased from baseline at two (23.9 ± 2.9 mmol/L, P < .005) and by 280% at 4 weeks (P < .01). Conclusions: Correcting acidosis by oral administration of sodium bicarbonate rapidly increases the urine excretion of soluble α-Klotho in CKD patients. However, a 4-week bicarbonate treatment was not able to increase serum α-Klotho. A longer study may confirm this pilot observation and increase serum Klotho, which has been shown to exert a protective cardiovascular effect during CKD.