Retinol-binding protein is an independent risk factor for hospitalization events in patients undergoing hemodialysis

Objective To explore the risk factors related to hospitalization events in out patients on hemodialysis and to evaluate the effect of serum retinol-binding protein (RBP) level on hospitalization events in patients on hemodialysis. Methods Case-control study. A total of 80 patients on dialysis were recruited, including 47 men (58.8%) and 33 women (41.2%), with an average age of (60.9±11.7) years (range: 32-89 years) and a median dialysis age of 43.6 months. Dialysis-related data were collected, the serum RBP level was detected using the ELISA method. Patients were followed-up until June 30, 2019, to record the events associated with all kinds of hospitalization events. The t-test, Mann-Whitney U test and chi-square test were used to compare the differences between the hospitalized event group and the non-event group. Multivariate logistic regression was used to analyze the related risk factors of hospitalization events. The Kaplan-Meier method, Log-rank test, and Cox proportional hazards regression model were used to analyze survival data. Results During the 19-month follow-up period, 26/80 patients (32.5%) had 67 events of hospitalization. There was no difference (P>0.05) in age, sex composition, dialysis age, ratio of diabetes/hypertension, interval dialysis weight gain (IDWG), systolic/diastolic blood pressure before dialysis, kt/v and URR between the groups with or without hospitalization events. The cut-off point of serum RBP was calculated using the patient′s highest Youden index. The patients were divided into the high-RBP group (n=44) and low-RBP group (n=36) according to the level of 165.34 mg/L. The incidence of hospitalization events in the high-RBP group was higher than that in the low-RBP group (45.45%>16.67%, P=0.006). Using the multivariate logistic regression model, after adjusting for sex, age, albumin and total cholesterol (CHO), only the serum RBP level was independently correlated with hospitalization events. The high-RBP group had an odds ratio (OR) of 3.64 (95%CI, 1.14-11.58; P=0.029) compared with the low-level group in hospitalization events. The Kaplan-Meier survival analysis showed that the incidence of hospitalization events in the high-RBP group was significantly higher than that in the low-RBP group (P=0.0058). The test results of the multivariable Cox proportional hazards regression model showed that for patients on hemodialysis, an elevated serum RBP level is an independent risk factor for hospitalization events. Conclusion Elevated serum RBP level is correlated with hospitalization events in patients on hemodialysis. RBP is an independent risk factor for hospitalization events in outpatients on hemodialysis. Key words: Retinol-binding proteins; Renal dialysis; Risk factors