Blood Pressure and Cardiovascular Events and Mortality in Maintenance Hemodialysis: A Nationwide Cohort Study

Background: Despite the high risk for cardiovascular event in ESKD patients, the optimal target blood pressure (BP) in these patients remains unclear. Therefore, this study aimed to investigate the association between blood pressure and adverse outcome in ESKD patients on maintenance hemodialysis. Methods: A total of 40,065 patients receiving maintenance hemodialysis were included from the Periodic Hemodialysis Quality Assessment conducted by the Health Insurance Review and Assessment Service. Participants were categorized into 5 groups according to mean pre-dialysis SBP during the assessment period; <120, 120–129, 130–139, 140–149, and ≥150 mmHg. The primary outcome was a composite of nonfatal cardiovascular events (nonfatal myocardial infarction, coronary revascularization, nonfatal stroke, or hospitalization for heart failure) or all-cause mortality (major adverse cardiac and cerebrovascular events [MACCEs]). Results: During a follow-up period of 230,750 person-years (median 6.1 years), MACCEs and all-cause death occurred in 26,268 patients (65.6%) and 23,049 patients (57.5%), respectively. Higher pre-dialysis SBP was associated with linearly higher incidence of MACCE (81.4, 99.9, 110.1, 116.2, and 131.3 events per 1000 person-years with increasing SBP categories). In the multivariable Cox proportional hazards model, the hazard ratios (95% confidence intervals) for MACCEs were 0.92 (0.86–0.99), 1.07 (1.03–1.12), 1.14 (1.09–1.19), and 1.27 (1.21–1.32) for the <120, 130–139, 140–149, and ≥150 mmHg SBP groups, respectively, compared with the reference group of 120–129 mmHg. When SBP was treated as a continuous variable, each 10mmHg increase was associated with a 1.07-fold higher risk of MACCE. Subgroup analysis revealed a significant interaction between SBP and interdialytic weight gain (IDWG, %), indicating that in patients with higher IDWG, the benefit of lowering SBP to below 120 mmHg was eliminated, while the risks associate with higher SBP was more pronounced. Conclusion: In patients on maintenance hemodialysis, pre-dialysis SBP was linearly associated with the risk of MACCEs. However, the magnitude of risk varied according to the degree of IDWG, suggesting the need for individualized consideration of volume status when interpreting SBP targets in this population.