Postdialysis blood pressure is a better predictor of mortality than predialysis blood pressure in Japanese hemodialysis patients: the Japan Dialysis Outcomes and Practice Patterns Study

Target blood pressure in Korean hemodialysis patients for optimal survival

BACKGROUND

Hypertension is a major cardiovascular risk factor in hemodialysis patients. This study identified the optimal blood pressure (BP) target for Korean hemodialysis patients using the Korean Renal Dialysis System (KORDS) dataset from the Korean Society of Nephrology and a pooled analysis for previous studies.

METHODS

Hemodialysis patients were classified according to their systolic (SBP) and diastolic BP (DBP) at intervals of 20 and 10 mmHg, respectively. As a primary and secondary outcome, all-cause mortality and cardiovascular mortality were evaluated. Subsequently, pooled analysis with previous literatures was performed.

RESULTS

Among 70,607 patients, 13,708 (19.4%) died in 2,426 days (interquartile range, 1,256-4,075 days). Mean SBP and DBP were 143.0 ± 19.6 and 78.5 ± 12.0 mmHg. In multivariable Cox regression, the patients with SBP of <120 and ≥180 mmHg showed 1.10- and 1.12-times increased risk of all-cause mortality compared to SBP of 120-140 mmHg. Meanwhile, DBP showed no significant association. In subgroup analysis, patients aged <70 years and without diabetes had a U-shaped SBP-mortality association. Cardiovascular mortality was increased in SBP of ≥160 mmHg compared to 120-140 mmHg, but it was not in <120 mmHg. Pooled analysis with previous studies mostly showed elevated risk in SBP of <120 mmHg, but the risks in 140-160 and 160-180 mmHg were not consistent.

CONCLUSION

Extremely lowering BP (<120 mmHg) or uncontrolled hypertension (≥160 mmHg) should be avoided to optimize survival in Korean hemodialysis patients. Detailed analysis for patients with SBP of 120-160 mmHg should be studied further under uniform BP measurement, along with consideration of risk of intradialytic hypotension. Tailored recommendations regarding patient risk factors also should be considered.

Optimal timing for post-dialysis blood pressure measurement: relationship with home blood pressure monitoring

In hemodialysis patients, blood pressure (BP) measured at the postdialysis period (POSBP) can be used to diagnose hypertension. However, the optimal time point for POSBP remains uncertain. This cross-sectional study evaluated 210 long-term dialysis patients (66.7% men; age = 56.9 ± 15.7 years), who underwent POSBP measurements at three time points [immediately after dialysis period ended (POSBP1); after blood return (POSBP2) and after fistula hemostasis or catheter sealing (POSBP3)] and home BP monitoring (HBPM) over one week. POSBP1, POSBP2, POSBP3 and HBPM values were 139.1 ± 22.4/73.2 ± 12.5, 142.8 ± 22.8/74.3 ± 12.3, 142.8 ± 21.8/74.0 ± 12.2 and 131.2 ± 21.2/77.9 ± 12.1 mmHg, respectively. Systolic POSBP3 and POSBP2 were significantly greater (p < 0.05) than systolic POSBP1. POSBP3 had the greatest correlation with HBPM, while elevated (>130/80 mmHg) POSBP3 showed the highest numerical accuracy (AUC [95% CI] = 0.696 [0.638-0.754]) and concordance (kappa coefficient = 0.41) with elevated HBPM (≥130/80 mmHg) compared with POSBP1 and POSBP2. These findings suggest that POSBP3 may be a preferable measurement for assessment of POSBP in hemodialysis patients.

Pulse pressure modifies the association between diastolic blood pressure and decrease in kidney function: the Japan Specific Health Checkups Study

Background

Unlike systolic blood pressure (SBP), the prognostic value of diastolic blood pressure (DBP) in kidney function has not been established. We hypothesized that pulse pressure (PP), which is associated with arteriosclerosis, would affect the prognostic value of DBP.

Methods

This longitudinal study used data from the Japan Specific Health Checkups Study was conducted between 2008 and 2014. The participants were stratified into three PP subgroups (low PP ≤39, normal PP 40-59 and high PP ≥60 mmHg). The exposures of interest were SBP and DBP, and the association between SBP/DBP and kidney outcomes (30% decline in the estimated glomerular filtration rate from baseline) was examined in each PP subgroup using a Cox proportional hazards model.

Results

Among 725 022 participants, 20 414 (2.8%) developed kidney outcomes during a median follow-up period of 34.6 months. Higher SBP was consistently associated with a higher incidence of kidney outcome in all PP subgroups. Although DBP had a positive linear association with the incidence of kidney outcome in low- and normal-PP subgroups, both lower (≤60 mmHg) and higher (≥101 mmHg) DBP were associated with a higher incidence of kidney outcome in the high-PP subgroup, with a U-shaped curve. Hazard ratios (95% confidence intervals) of ≤60 mmHg (reference: 61-80 mmHg in normal-PP subgroup) and ≥101 mmHg were 1.26 (1.15-1.38) and 1.86 (1.62-2.14), respectively.

Conclusions

In this large population-based cohort, DBP was differently associated with kidney outcome by PP level; lower DBP was significantly associated with a higher incidence of kidney outcome in the high-PP subgroup but not in the low- and normal-PP subgroups.

Seasonal variation and predictors of intradialytic blood pressure decline: a retrospective cohort study

The risk factors for intradialytic systolic blood pressure decline remain poorly understood. We aimed to identify clinical and laboratory predictors of the intradialytic systolic blood pressure decline, considering its seasonal variation. In a retrospective cohort of 47,219 hemodialysis sessions of 307 patients undergoing hemodialysis over one year in three dialysis clinics, the seasonal variation and the predictors of intradialytic systolic blood pressure decline (predialysis systolic blood pressure--nadir intradialytic systolic blood pressure) were assessed using cosinor analysis and linear mixed models adjusted for baseline or monthly hemodialysis-related variables, respectively. The intradialytic systolic blood pressure decline was greatest and least in the winter and summer, respectively, showing a clear seasonal pattern. In both models adjusted for baseline and monthly hemodialysis-related parameters, calcium channel blocker use was associated with a smaller decline (-4.58 [95% confidence interval (CI), -5.84 to -3.33], P < 0.001; -3.66 [95% CI, -5.69 to -1.64], P < 0.001) and α blocker use, with a greater decline (3.25 [95% CI, 1.53-4.97], P < 0.001; 3.57 [95% CI, 1.08-6.06], P = 0.005). Baseline and monthly serum phosphorus levels were positively correlated with the decline (1.55 [95% CI, 0.30-2.80], P = 0.02; 0.59 [95% CI, 0.16-1.00], P = 0.007), and baseline and monthly normalized protein catabolic rates were inversely correlated (respectively, -22.41 [95% CI, -33.53 to -11.28], P < 0.001; 9.65 [95% CI, 4.60-14.70], P < 0.001). In conclusion, calcium channel blocker use, α blocker avoidance, and serum phosphorus-lowering therapy may attenuate the intradialytic systolic blood pressure decline and should be investigated in prospective trials.

Intradialytic systolic blood pressure variation can predict long-term mortality in patients on maintenance hemodialysis

PURPOSE

It is unclear which time-points of intradialytic blood pressure (BP) best predict prognosis. Thus, it is important to assess the association between different time-points of intradialytic BP and prognosis in clinical practice.

METHODS

We recruited patients who underwent hemodialysis from January 2014 to June 2014. Data about dialysis were collected, including intradialytic BP. Cox regression analysis was performed to examine the association between different time-points of intradialytic BP and clinical events, with a follow-up through December 31, 2019. The primary endpoint was all-cause mortality.

RESULTS

A total of 216 patients were recruited and 62 (30.7%) patients died (6.1 per 100-person year) during the follow-up. Intradialytic SBP varied greatly in fatalities. Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 1.80 and 5.06 when intradialytic systolic blood pressure (SBP) variation was analyzed in increments of 20 mmHg. Furthermore, we divided intradialytic SBP variation into three categories: < 15 mmHg, 15 ~ 30 mmHg,  ≥ 30 mmHg. Kaplan-Meier analysis indicated that both all-cause mortality and cardiovascular mortality increased significantly for patients with intradialytic SBP variation over 30 mmHg (P = 0.006 and 0.021). Univariate and multivariate Cox regression models indicated that the adjusted hazard ratio for death was 3.78 and 12.62 as intradialytic SBP variation ≥ 30 mmHg vs. intradialytic SBP variation < 15 mmHg.

CONCLUSION

Intradialytic SBP variation, rather than BP of specific intradialytic time-points, has the potential to predict long-term mortality in hemodialysis patients. BP stability is crucial for patients' prognosis.