Introduction:
This study aimed to clarify the potential association of serum soluble α-klotho levels with all-cause mortality in Chinese patients on maintenance hemodialysis (MHD).

Material and methods:
The present study is a single-center prospective cohort study. It included 134 MHD patients who were divided into two groups according to the median level of serum α-klotho: 68 patients in the low soluble α-klotho group (< 1.15 ng/ml and equivalent to 1.15 ng/ml) and 66 patients in the high soluble α-klotho group (> 1.15 ng/ml). These patients were followed up for 36 months. The three-year all-cause mortality rate, overall survival (OS) and cardio-cerebrovascular mortality were observed. The potential risk factors of all-cause mortality in MHD patients were investigated by Cox regression models.

Results:
The 3-year all-cause mortality rates in the low soluble α-klotho group were significantly higher than those in the high soluble α-klotho group (33.82% vs. 16.67%, p = 0.039). The difference of the 3-year cardio-cerebrovascular mortality rates between the two groups was non-significant (26.47% vs. 15.15%, p = 0.107). The Kaplan-Meier analysis showed that the differences in the rates of OS and cardio-cerebrovascular death free survival between the two groups were significantly different (all p < 0.05). The Cox regression analyses revealed that low soluble α-klotho level was an independent predictor of all-cause mortality in MHD patients after adjusting for potential confounding factors.

Conclusions:
Low serum soluble α-klotho levels were associated with increased risk of all-cause mortality in Chinese MHD patients.