Intradialytic Hypertension and Risk of Long-Term Mortality

Hypertension is a common comorbidity among patients receiving maintenance dialysis. Increases in systolic blood pressure from pre- to post-hemodialysis (intradialytic hypertension) occur in a subset of hemodialysis patients. Results of previous studies in patients with intradialytic hypertension have shown adverse short- and long-term outcomes. However, according to Anika T. Singh, MD, MMSc, and colleagues, there is little consensus on an evidence-based definition.

During a virtual poster session at ASN Kidney Week 2021, the researchers reported results of a retrospective cohort study designed to examine the association of various definitions of intradialytic hypertension with all-cause mortality. The poster was titled Association of Different Definitions of Intradialytic Hypertension with Long-Term Mortality in Hemodialysis.

Intradialytic hypertension was defined as ≥30% of baseline sessions with an increase in pre- to post-hemodialysis systolic blood pressure of (1) ≥0 mmHg (Hyper0); (2) ≥10 mmHg (Hyper10); or (3) ≥20 mmHg increase (Hyper20). Unadjusted and adjusted Cox proportional hazards models were used to examine the association of the three definitions with all-cause mortality. Interaction terms were used to assess for effect modification according to pre-specified variables, including demographic (age, sex), hemodialysis-related (pre-hemodialysis systolic blood pressure, ultrafiltration rate), and comorbidities (diabetes, heart failure, and peripheral artery disease [PVD]).

The cohort included 3198 participants. At baseline, mean age was 62 years, 57% were male, and 14% were Black. The average change in blood pressure from pre- to post-hemodialysis was 13 mmHg.

During the baseline period, 47% of participants met the Hyper0 definition and were at 29% higher adjusted risk of death (HR, 1.29; 95% confidence interval [CI], 1.03-1.62 ), compared with those with no increase in systolic blood pressure. Twenty-one point two percent of participants met the definition of Hyper10, which was associated with a 21% higher adjusted risk of death (HR, 1.21; 95% CI, 0.96 to 1.51). Hyper20 was present in 6.8% of participants and was associated with a 5% higher risk of death (HR, 1.05; 95% CI, 0.76-1.46).

There was evidence of effect modification by age and PVD (P for interaction = .02 for both). The risk of death was higher in participants 45 to 70 years of age and in those without PVD.

“Individuals with any increase in systolic blood pressure from pre- to post-hemodialysis experienced the highest adjusted risk of mortality, compared with other threshold-based definitions with effect modification by age and PVD,” the researchers said.

Source: Singh AT, Waikar SS, McCausland F. Association of different definitions of intradialytic hypertension with long-term mortality in hemodialysis. Abstract of a poster presented at the American Society of Nephrology virtual Kidney Week 2021 (Abstract PO0878), November 2021.