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 <140/90 mm Hg; 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 130-159 mm Hg, mortality was 13% higher in facilities with 20% more patients at systolic blood pressure of 110-129 mm Hg and 16% higher in facilities with 20% more patients at systolic blood pressure of ≥160 mm Hg. For patient-level systolic blood pressure, mortality was elevated at low (<130 mm Hg), not high (≥180 mm Hg), systolic blood pressure. For predialysis diastolic blood pressure, mortality was lowest at 60-99 mm Hg, a wide range implying less chance to improve outcomes. Higher mortality at systolic blood pressure of <130 mm Hg is consistent with prior studies and may be due to excessive blood pressure lowering during dialysis. The lowest risk facility systolic blood pressure of 130-159 mm Hg 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.

Figure 1

(A) Distribution of Patient-Level Pre-Dialysis SBP (by Region) (B) Distribution of Facility-Level Pre-Dialysis SBP (Overall) n=25,907 HD patients from 922 facilities in DOPPS I–III with ESRD duration >180 days. Europe/ANZ includes France, Germany, Italy, Spain, U.K., Belgium, Sweden, Australia, and New Zealand. North America includes U.S. and Canada. The mean (SD) of pre-dialysis SBP in Europe/ANZ, North America, and Japan were 141 (24), 151 (24), and 151 (22) mm Hg, respectively.

Figure 1

(A) Distribution of Patient-Level Pre-Dialysis SBP (by Region) (B) Distribution of Facility-Level Pre-Dialysis SBP (Overall) n=25,907 HD patients from 922 facilities in DOPPS I–III with ESRD duration >180 days. Europe/ANZ includes France, Germany, Italy, Spain, U.K., Belgium, Sweden, Australia, and New Zealand. North America includes U.S. and Canada. The mean (SD) of pre-dialysis SBP in Europe/ANZ, North America, and Japan were 141 (24), 151 (24), and 151 (22) mm Hg, respectively.

Figure 2

(A) Distribution of Patient-Level Pre-Dialysis DBP (by Region) (B) Distribution of Facility-Level Pre-Dialysis DBP (Overall) n=25,836 HD patients from 921 facilities in DOPPS I–III with ESRD duration >180 days. Abbreviations: See footnote of Figure 1A–B. The mean (SD) of pre-dialysis DBP in Europe/ANZ, North America, and Japan were 76 (14), 79 (15), and 79 (13) mm Hg, respectively.

Figure 2

(A) Distribution of Patient-Level Pre-Dialysis DBP (by Region) (B) Distribution of Facility-Level Pre-Dialysis DBP (Overall) n=25,836 HD patients from 921 facilities in DOPPS I–III with ESRD duration >180 days. Abbreviations: See footnote of Figure 1A–B. The mean (SD) of pre-dialysis DBP in Europe/ANZ, North America, and Japan were 76 (14), 79 (15), and 79 (13) mm Hg, respectively.

Figure 3

(A) Mortality by Patient-Level Pre-Dialysis SBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Pre-Dialysis SBP Categories (Fully-Adjusted) n=24,525 HD patients from 920 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with pre-dialysis SBP <110 mm Hg. Cox models were stratified by geographic region and study phase, accounting for facility-clustering effects, and adjusted for all demographics, comorbid conditions, and labs listed in Table 1. Facility-level analyses were adjusted additionally for 5 facility practices. For this and subsequent figures, vertical lines represent 95% confidence intervals (CIs). HR=Hazard Ratio. *0.01≤p<0.05; **0.001≤p<0.01; ***p<0.001.

Figure 3

(A) Mortality by Patient-Level Pre-Dialysis SBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Pre-Dialysis SBP Categories (Fully-Adjusted) n=24,525 HD patients from 920 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with pre-dialysis SBP <110 mm Hg. Cox models were stratified by geographic region and study phase, accounting for facility-clustering effects, and adjusted for all demographics, comorbid conditions, and labs listed in Table 1. Facility-level analyses were adjusted additionally for 5 facility practices. For this and subsequent figures, vertical lines represent 95% confidence intervals (CIs). HR=Hazard Ratio. *0.01≤p<0.05; **0.001≤p<0.01; ***p<0.001.

Figure 4

(A) Mortality by Patient-Level Pre-Dialysis DBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Pre-Dialysis DBP Categories (Fully-Adjusted) n=25,424 HD patients from 919 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with pre-dialysis DBP <50 mm Hg. Cox models are as described for Figure 3.

Figure 4

(A) Mortality by Patient-Level Pre-Dialysis DBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Pre-Dialysis DBP Categories (Fully-Adjusted) n=25,424 HD patients from 919 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with pre-dialysis DBP <50 mm Hg. Cox models are as described for Figure 3.

Figure 5

(A) Mortality by Patient-Level Pre-Dialysis SBP Categories (Stepwise Adjustment) (B) Mortality by Facility-Level Pre-Dialysis SBP Categories (Stepwise Adjustment) n=24,525 patients, as described for Figure 3. ^a=adjusted for demographics in Table 1; ^b=adjusted for demographics, comorbid conditions, and labs in Table 1. For the facility-level SBP model, adjustment additionally for facility practices altered the HR slightly (as shown in Figure 3B).

Figure 5

(A) Mortality by Patient-Level Pre-Dialysis SBP Categories (Stepwise Adjustment) (B) Mortality by Facility-Level Pre-Dialysis SBP Categories (Stepwise Adjustment) n=24,525 patients, as described for Figure 3. ^a=adjusted for demographics in Table 1; ^b=adjusted for demographics, comorbid conditions, and labs in Table 1. For the facility-level SBP model, adjustment additionally for facility practices altered the HR slightly (as shown in Figure 3B).

Figure 6

(A) Mortality by Patient-Level Pre-Dialysis DBP Categories (Stepwise Adjustment) (B) Mortality by Facility-Level Pre-Dialysis DBP Categories (Stepwise Adjustment) n=25,424 patients, as described for Figure 4. ^a=adjusted for demographics in Table 1; ^b=adjusted for demographics, comorbid conditions and labs in Table 1. For the facility-level DBP model, adjustment additionally for facility practices altered the HR slightly (as shown in Figure 4B).

Figure 6

(A) Mortality by Patient-Level Pre-Dialysis DBP Categories (Stepwise Adjustment) (B) Mortality by Facility-Level Pre-Dialysis DBP Categories (Stepwise Adjustment) n=25,424 patients, as described for Figure 4. ^a=adjusted for demographics in Table 1; ^b=adjusted for demographics, comorbid conditions and labs in Table 1. For the facility-level DBP model, adjustment additionally for facility practices altered the HR slightly (as shown in Figure 4B).

Figure 7

(A) Mortality by Patient-Level Post-Dialysis SBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Post-Dialysis SBP Categories (Fully-Adjusted) n=24,303 HD patients from 915 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with post-dialysis SBP <100 mm Hg. Cox models are as described for Figure 3.

Figure 7

(A) Mortality by Patient-Level Post-Dialysis SBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Post-Dialysis SBP Categories (Fully-Adjusted) n=24,303 HD patients from 915 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with post-dialysis SBP <100 mm Hg. Cox models are as described for Figure 3.

Figure 8

(A) Mortality by Patient-Level Post-Dialysis DBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Post-Dialysis DBP Categories (Fully-Adjusted) n=24,805 HD patients from 911 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with post-dialysis DBP <50 mm Hg. Cox models are as described for Figure 3.

Figure 8

(A) Mortality by Patient-Level Post-Dialysis DBP Categories (Fully-Adjusted) (B) Mortality by Facility-Level Post-Dialysis DBP Categories (Fully-Adjusted) n=24,805 HD patients from 911 facilities in DOPPS I–III with ESRD duration >180 days, excluding patients with post-dialysis DBP <50 mm Hg. Cox models are as described for Figure 3.