Abstract: Objective  This study aimed to determine the relationship bewteen serum Chitinase 3-like Protein 1 (CHI3L1) and the mortality of patients with end-stage renal disease (ESRD) on haemodialysis (HD) and to evaluate the prognostic value of serum CHI3L1.  Methods  It was a prospective cohort study of kidney failure patients on HD at Peking University Third Hospital in September 2014 and were followed up until December 2023. Baseline serum CHI3L1 levels were measured using enzyme-linked immunosorbent assay (ELISA), then patients were divided into two groups (high-CHI3L1 group and low-CHI3L1 group) based on median CHI3L1. Overall survival and cardiovascular mortality were analyzed by the Kaplan-Meier method. The restricted cubic spline (RCS) curve was used to model and depict the relationship between baseline CHI3L1 and the risk of all-cause mortality in HD patients. The influence of CHI3L1 on outcome was analyzed using Cox regression method.  Results  109 prevalent patients were enrolled. The follow-up period was 80.0 (38.2, 113.2) months. Kaplan-Meier survival analysis showed that all-cause mortality of patients in high-CHI3L1 group was significantly higher than that in low-CHI3L1 group (χ2=4.720, P=0.030), and there was no significant difference in cardiovascular mortality between these two groups (χ2=1.954, P=0.162). When CHI3L1≥199.8 ng/ml, all-cause mortality significantly increased with the increase of CHI3L1 level (HR=1.747; 95% CI: 1.035～2.947, P =0.037). COX regression analysis showed that older age (HR=1.029, 95% CI：1.001～1.056, P =0.040), longer dialysis vintage (HR=2.251, 95% CI：1.310～3.868, P=0.003), higher systolic blood pressure (HR=1.022, 95% CI：1.008～1.036, P=0.002) and lower serum creatinine level (HR=0.13, 595% CI：0.064～0.28, P＜0.001) were independent risk factors for all-cause mortality. After adjusting these factors, high CHI3L1 remained to be an independent predict factor for all-cause mortality in HD patients (HR=1.963, 95% CI: 1.010-3.813, P=0.047).   Conclusions   The study suggested that all-cause mortality of HD patients in high-CHI3L1 group was significantly higher than that of patients in low-CHI3L1 group. Serum CHI3L1 was independently associated with all-cause mortality in HD patients.

Key words: Chitinase 3-like Protein 1, Hemodialysis, Prognosis, All-cause mortality, Cardiovascular disease