Correlation of hematocrit and cardiovascular events in peritoneal dialysis patients

Abstract

Objective: To investigate the correlation between hematocrit (HCT) and cardiovascular events in peritoneal dialysis (PD) patients. Methods: Patients undergoing maintenance PD in the PD center of Guizhou Provincial People's Hospital from March 19, 2012 to July 9, 2020 were included. Demographic, baseline clinical and laboratory data of the patients were collected and patients were followed up until April 8, 2022. The primary endpoint was the first occurrence of a cardiovascular event. According to the tertiles of baseline HCT, the patients were divided into group Q1 (HCT≤26.6%), group Q2 (HCT>26.6%-32.4%), and group Q3 (HCT>32.4%). Laboratory indexes and cardiovascular events were compared among the three groups. Kaplan-Meier survival curve, Cox regression analysis and sensitivity analysis were used to analyze the effect of HCT on cardiovascular outcomes. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of HCT for cardiovascular events in PD patients. Results: A total of 860 PD patients were included, including 494 males (57.4%) and 366 females (42.6%), with a mean age of (41.5±15.0) years. There were 287 cases in group Q1, 289 cases in group Q2, and 284 cases in group Q3, respectively. A total of 265 (30.8%) patients experienced first cardiovascular events during the follow-up period. The incidence of cardiovascular events in groups Q1, Q2 and Q3 was 36.2% (104/287), 34.3% (99/289), and 21.8% (62/284), respectively, with a statistically significant difference (P<0.001). The incidence of cardiovascular events decreased with the increase of HCT. Multivariate Cox proportional hazards regression model analysis showed that decreased HCT was a risk factor for cardiovascular events. Compared with group Q3, the risk of cardiovascular events in group Q1 increased by 50.7% (group Q2: HR=1.444, 95%CI: 1.029-2.028, P=0.034; group Q1: HR=1.570, 95%CI: 1.096-2.250, P=0.014). In the sensitivity analysis, using kidney transplantation as the competition event, the risk of cardiovascular events was lower in group Q3 than that in group Q1 (subdistributional HR=1.413, 95%CI: 1.006-1.990, P=0.046). Kaplan-Meier survival curve showed that compared with the other two groups, the cardiovascular events-free survival rate of patients in group Q1 was significantly lower (log-rank χ2=9.722, P=0.008). ROC analysis showed that the area under the curve (AUC) of HCT for predicting cardiovascular events in PD patients was 0.583 (95%CI: 0.542-0.623, P<0.001), with the sensitivity of 40.6% and the specificity of 75.1%. Conclusion: Low-level HCT is associated with an increased risk of the first cardiovascular event in PD patients.