Association of Different Definitions of Intradialytic Hypertension with Long-Term Mortality in Hemodialysis

Abstract

Background: Hypertension is common in hemodialysis patients. A subset of patients experience systolic blood pressure increases from prehemodialysis to posthemodialysis (intradialytic hypertension), which are associated with adverse outcomes. However, little consensus exists on an evidence-based definition. Methods: In 3198 hemodialysis patients, Cox models were fit to examine the association of various definitions of intradialytic hypertension (≥30% of baseline sessions with an increase in prehemodialysis to posthemodialysis systolic blood pressure of (1) ≥0 mm Hg [Hyper0]; (2) ≥10 mm Hg [Hyper10], or (3) ≥20 mm Hg increase [Hyper20]) with all-cause mortality. Effect modification was assessed using interaction terms according to prespecified variables. Results: At baseline, mean age was 62±15 years, 57% were male, and 14% of patients were Black. During the baseline period, 47% of individuals met the Hyper0 definition and experienced 32% (hazard ratio, 1.32 [95% CI, 1.05-1.66]) higher adjusted risk of death, compared with no systolic blood pressure increase. Hyper10 was present in 21.2% and associated with 18% higher adjusted risk of death (hazard ratio, 1.18 [95% CI, 0.94-1.48]). Hyper20 was present in 6.8% and associated with 3% higher adjusted risk of death (hazard ratio 1.03 [95% CI, 0.74-1.44]). Effect modification by age and peripheral vascular disease was observed (P interaction=0.04 for age and 0.02 for peripheral vascular disease), with higher associated risk of death for those aged 45 to 70 years and those without peripheral vascular disease. Conclusions: Individuals with any systolic blood pressure increase from prehemodialysis to posthemodialysis had the highest adjusted risk of mortality, compared with other threshold-based definitions.