Serum Klotho, Cardiovascular Events, and Mortality in Nondiabetic Chronic Kidney Disease

Background: Experimental studies indicate that Klotho deficiency is a pathogenic factor for CKD-related complications, including cardiovascular disease (CVD). However, the association between serum Klotho and clinical outcomes in nondiabetic CKD patients needs to be further clarified. We aimed to determine whether serum Klotho levels are associated with CVD events and mortality in predialysis CKD patients without diabetes. Methods: A total of 336 CKD stage 2-5 predialysis patients without diabetes were recruited and followed from the end of 2014 to January 2019 for CVD events and overall mortality. Serum Klotho was detected by ELISA and divided into quartiles (lowest, middle, second highest, and highest quartiles) according to their serum Klotho category. Results: After a median follow-up of 3.52 years (IQR 3.34-3.76), Kaplan-Meier analysis showed that, compared to participants with a Klotho level in the highest quartile (the reference category), those in the lowest Klotho quartile were associated with a higher all-cause mortality risk (HR = 7.05; 95% CI 1.59-31.25) and a higher CVD event risk (HR = 3.02; 95% CI 1.45-6.30). In addition, the middle Klotho quartile was also associated with CVD event risk (HR = 2.56; 95% CI 1.21-5.41). Moreover, in the multivariate-adjusted model, the lowest Klotho quartile remained significantly associated with all-cause mortality (HR = 5.17; 95% CI 1.07-24.96), and the middle Klotho quartile maintained a significant association with CVD event risk (HR = 2.32; 95% CI 1.03-5.21). Conclusion: These results suggest that lower serum Klotho levels are independently associated with overall mortality and CVD events in nondiabetic predialysis CKD patients.