[Effect of pre-dialysis blood pressure on all-cause and cardiovascular disease mortality in patients on maintenance hemodialysis].

Objective: To investigate the effect of pre-dialysis blood pressure (Pre-BP) on all-cause and cardiovascular disease (CVD) mortality in patients on maintenance hemodialysis (MHD). Methods: This single-center, retrospective cohort study enrolled patients undergoing first-time hemodialysis between January 1, 2007, and June 30, 2021, from the dialysis registry of the First Affiliated Hospital, Zhejiang University School of Medicine. General information and laboratory parameters were collected. Pre-dialysis systolic blood pressure (Pre-SBP) and pre-dialysis diastolic blood pressure (Pre-DBP) were calculated and averaged at 4-6 months after dialysis. The mean Pre-SBP and Pre-DBP values were used as continuous variables, and restricted cubic spline (RCS) curves were used to assess the relationship between Pre-BP and mortality risk. Patients were subsequently divided into six groups for Pre-DBP and six groups for Pre-SBP combined with Pre-DBP. Survival analyses were performed using the Kaplan-Meier method. All-cause and CVD mortality were compared between groups using the log-rank test. Multivariate Cox regression models were used to analyze the associations between Pre-BP and all-cause and CVD mortality. Results: A total of 1 213 patients were enrolled. By the end of follow-up, 175 patients (14.4%) had died, of whom 62 (35.4%) died from CVD. Kaplan-Meier survival curves showed that the Pre-DBP<65 mmHg group (1 mmHg=0.133 kPa) had a significantly lower cumulative survival rate (χ²=90.52, P<0.001) and a significantly higher CVD mortality rate (χ²=35.54, P<0.001) than the other groups. The combined Pre-SBP and Pre-DBP analysis showed that the Pre-SBP≥150 mmHg and Pre-DBP<80 mmHg groups had a significantly lower cumulative survival rate (χ²=45.58, P<0.001) and a significantly higher CVD mortality rate (χ²=30.13, P<0.001) than the other groups. Multivariate Cox regression model analysis showed that compared with other groups, the risk of MHD all-cause mortality was increased in the Pre-DBP<65 mmHg group and the Pre-SBP≥150 mmHg and Pre-DBP<80 mmHg group [HR (95%CI)=1.927 (1.195-3.109), 3.298 (1.567-6.939), both P<0.05]. Conclusion: In patients undergoing MHD, Pre-DBP<65 mmHg or Pre-SBP≥150 mmHg and Pre-DBP<80 mmHg were independent risk factors for all-cause mortality, with a low cumulative survival rate and a high risk of CVD mortality.