Blood pressure levels and mortality risk among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

Abstract

KDOQI practice guidelines recommend predialysis blood pressure <140/90mmHg; however, most prior studies had found elevated mortality with low, not high, systolic blood pressure. This is possibly due to unmeasured confounders affecting systolic blood pressure and mortality. To lessen this bias, we analyzed 24,525 patients by Cox regression models adjusted for patient and facility characteristics. Compared with predialysis systolic blood pressure of 130–159mmHg, mortality was 13% higher in facilities with 20% more patients at systolic blood pressure of 110–129mmHg and 16% higher in facilities with 20% more patients at systolic blood pressure of ≥160mmHg. For patient-level systolic blood pressure, mortality was elevated at low (<130mmHg), not high (≥180mmHg), systolic blood pressure. For predialysis diastolic blood pressure, mortality was lowest at 60–99mmHg, a wide range implying less chance to improve outcomes. Higher mortality at systolic blood pressure of <130mmHg is consistent with prior studies and may be due to excessive blood pressure lowering during dialysis. The lowest risk facility systolic blood pressure of 130–159mmHg indicates this range may be optimal, but may have been influenced by unmeasured facility practices. While additional study is needed, our findings contrast with KDOQI blood pressure targets, and provide guidance on optimal blood pressure range in the absence of definitive clinical trial data