Association of blood pressure with all-cause mortality and stroke in Japanese hemodialysis patients: The Japan dialysis outcomes and practice pattern study

Bilateral Nephrectomy for Resistant Hypertension and Secondary Aldosteronism in a Hemodialysis Patient: A Case Report

A 42-year-old Japanese woman with end-stage renal failure due to hypertension presented with a systolic blood pressure of 160-200 mmHg despite treatment with 4 different antihypertensive agents. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were elevated. Adrenal vein sampling suggested bilateral excessive aldosterone secretion, whereas adrenocortical scintigraphy showed right-dominant accumulation. Open bilateral nephrectomy and right adrenalectomy improved the systolic blood pressure, PAC, and PRA. A pathological examination revealed zona glomerulosa hyperplasia but not microaldosteronoma. This report shows that bilateral nephrectomy, not unilateral adrenalectomy, is a potentially effective treatment option for resistant hypertension with an elevated renin-angiotensin-aldosterone system in hemodialysis patients.

Long-term peridialytic blood pressure changes are related to mortality

BACKGROUND

In chronic haemodialysis (HD) patients, the relationship between long-term peridialytic blood pressure (BP) changes and mortality has not been investigated.

METHODS

To evaluate whether long-term changes in peridialytic BP are related to mortality and whether treatment with HD or haemodiafiltration (HDF) differs in this respect, the combined individual participant data of three randomized controlled trials comparing HD with HDF were used. Time-varying Cox regression and joint models were applied.

RESULTS

During a median follow-up of 2.94 years, 609 of 2011 patients died. As for pre-dialytic systolic BP (pre-SBP), a severe decline (≥21 mmHg) in the preceding 6 months was independently related to increased mortality [hazard ratio (HR) 1.61, P = .01] when compared with a moderate increase. Likewise, a severe decline in post-dialytic diastolic BP (DBP) was associated with increased mortality (adjusted HR 1.96, P < .0005). In contrast, joint models showed that every 5-mmHg increase in pre-SBP and post-DBP during total follow-up was related to reduced mortality (adjusted HR 0.97, P = .01 and 0.94, P = .03, respectively). No interaction was observed between BP changes and treatment modality.

CONCLUSION

Severe declines in pre-SBP and post-DBP in the preceding 6 months were independently related to mortality. Therefore peridialytic BP values should be interpreted in the context of their changes and not solely as an absolute value.

Xanthine Oxidoreductase Inhibitor Use Associated With Reduced Risk of Sarcopenia and Severe Sarcopenia in Patients Undergoing Hemodialysis

Background

Xanthine oxidoreductase (XOR) inhibition reduces reactive oxygen species (ROS) production and enhances adenosine triphosphate (ATP) synthesis. We investigated the protective effects of XOR inhibitor treatment on sarcopenia, frequently observed in patients undergoing hemodialysis (HD), in which increased ROS and ATP shortage are known to be involved.

Methods

This retrospective cross-sectional study included 296 HD patient (203 males, 93 females). Muscle mass, physical performance, and muscle strength were assessed using dual-energy X-ray absorptiometry, five-time chair stand testing, and handgrip strength, respectively. The Asian Working Group for Sarcopenia 2019 criteria were used to define low muscle mass, low physical performance, and low muscle strength, as well as sarcopenia and severe sarcopenia.

Results

Sarcopenia and severe sarcopenia prevalence rates were 42.2 and 20.9%, respectively. XOR inhibitor users (n = 119) showed a significantly (p < 0.05) lower prevalence of sarcopenia and severe sarcopenia, as well as reduced muscle mass, physical performance, and muscle strength than non-users (n = 177). Multivariate logistic regression analyses also revealed XOR inhibitor use to be significantly associated with low muscle mass [odds ratio (OR), 0.384; 95% confidence interval (CI), 0.183–0.806; p = 0.011] and low physical performance (OR, 0.286; 95% CI, 0.142–0.578; p < 0.001), while significance with low muscle strength was borderline. Furthermore, XOR inhibitor use was significantly associated with sarcopenia (OR, 0.462; 95% CI, 0.226–0.947; p = 0.035) and severe sarcopenia (OR, 0.236; 95% CI, 0.091–0.614; p = 0.003).

Conclusions

XOR inhibitor use was significantly associated with reduced risk of sarcopenia/severe sarcopenia in HD patients, suggesting that XOR inhibitor treatment has protective effects on sarcopenia in HD patients.

Role of the new bioimpedance monitoring device (Seca®) in assessing dry weight in hemodialysis patients

BACKGROUND

In recent years, bioimpedance analysis has come to be widely used in clinical practice for dialysis patients, but there is not sufficient consensus on its significance. We aimed to examine the merits of performing bioimpedance analysis in addition to conventional evaluation methods for dry weight such as measuring human atrial natriuretic peptide (hANP), blood pressure, and cardiothoracic ratio in patients on chronic hemodialysis.

METHODS

Body composition of 78 hemodialysis patients was performed by using a new and more accurate segmental multifrequency bioimpedance analysis device (Seca^® medical body composition analyzer 525, Seca GmbH & Co. KG, Hamburg, Germany). Laboratory data including hANP at post-dialysis and demographic profile were collected. Statistical analysis was performed with SPSS software.

RESULTS

Mean age of the patients was 66.9 ± 12.6 years and 80.8% were males. Mean value of hANP and the ratio of extracellular water to total body water (ECW/TBW) were 61.4 ± 36.4 pg/mL and 46.1 ± 3.9%, respectively. The calculated ECW/TBW cutoff point for hANP > 50 pg/mL was 45.0%, with sensitivity of 74.4% and specificity of 64.7%. Patients with an ECW/TBW of more than 45% and hANP value of > 50 pg/mL had a higher blood pressure and cardiothoracic ratio on chest X-ray examination.

CONCLUSIONS

Our results suggest that the ratio of extracellular water to total body water of more than 45% and hANP value of ≥ 50 pg/mL were overhydrated in chronic hemodialysis patients. Whether monitoring levels of these parameters has a role in the outcome including patients' survival and cardiovascular events requires further study.

Central versus ambulatory blood pressure for predicting mortality and cardiovascular events in hemodialysis patients: a multicenter cohort study

OBJECTIVE

Studies in the general population suggest that central blood pressure (BP) may be superior to peripheral BP in risk assessment. Although ambulatory brachial BP is recognized as the most reliable BP measurement in the dialysis population, there is no comparison of office central BP with ambulatory BP regarding risk stratification in these patients.

METHODS

In a multicenter prospective study of dialysis patients, central BP was measured noninvasively on a midweek nondialysis day, with interdialytic ambulatory BP and predialysis BP also collected. The primary outcomes were a composite of major adverse cardiovascular events (MACE) and all-cause mortality. Agreement between central and ambulatory BP was assessed using Cohen's Kappa index and Bland--Altman plot. Linear and nonlinear Cox regression models were used to determine the association of BP parameters with outcomes.

RESULTS

A total of 368 patients were recruited and 366 underwent central BP measurement. Central BP had a moderate agreement with ambulatory BP in defining hypertension (κ = 0.42) with wide limits of agreement in Bland--Altman analysis. After a median follow-up of 51.5 months, central pulse pressure, ambulatory SBP and ambulatory pulse pressure were associated with all-cause mortality, whereas all BP parameters, except for predialysis DBP, were significant predictors of MACE. However, whenever evaluated in a stepwise variable selection Cox model, only ambulatory pulse pressure, but not any central BP, was determined as the best candidate for prediction of both all-cause mortality and MACE. Nonlinear Cox models revealed no significant nonlinear trend of the association between central BP and outcomes.

CONCLUSION

Central BP is predictive of all-cause mortality and cardiovascular events in dialysis patients but its prognostic value does not outperform ambulatory peripheral BP. Our data support the superiority of ambulatory BP in the dialysis population.

Association of optimal blood pressure with mortality in patients taking antihypertensive medications

We investigated the relationship between blood pressure (BP) and mortality in patients taking antihypertensive medications in the Korean using data from the 2007-2015 Korean National Health and Nutrition Examination Surveys. A total of 6601 patients aged 30-74 years were included. Systolic BP (SBP) and diastolic BP (DBP) were both divided into four groups as follows: SBP < 120, 120 ≤ SBP ≤ 129 130 ≤ SBP ≤ 139, and SBP ≥ 140; DBP < 70, 70 ≤ DBP ≤ 79, 80 ≤ DBP ≤ 89, and DBP ≥ 90. The survival rates and hazard ratios were evaluated using Kaplan-Meier curves and multivariable Cox regression analyses. To evaluate the predictability of all-cause mortality according to SBP and/or DBP, we calculated Harrell's concordance-index. The lowest DBP group had a high risk of mortality regardless of the SBP status. The group with DBP < 70 mm Hg and SBP ≥ 140 mm Hg showed the highest mortality. The discriminatory ability calculated using Harrell's C-indexes was greater for the combination of SBP and DBP compared to DBP or SBP alone. These results suggest that it is more effective to simultaneously evaluate the effect of SBP and DBP to predict mortality; clinicians should manage DBP < 70 mm Hg when treating hypertensive patients.

Peridialysis BP levels and risk of all-cause mortality: a dose-response meta-analysis

Blood pressure (BP) management posed great challenge in hemodialysis (HD) population. We conducted a dose-response meta-analysis to investigate the quantitative features and the potential threshold effect of the associations between peridialysis BP levels and all-cause mortality risk in HD population. We searched all of the prospective cohort studies (published before 18 March 2017) on the associations between peridialysis BP levels and all-cause mortality risk. A total of 229,688 prevalent HD patients from 8 studies were included. Significant non-linear associations were noted between peridialytic BP levels and all-cause mortality risk. Significant increased risk of death was found in four peridialysis BP ranges, that is, low levels of predialysis SBP (<135 mmHg, 140 mmHg as the reference), two extremes of predialysis DBP (<55 and >95 mmHg, 90 mmHg as the reference), high levels of postdialysis SBP (>180 mmHg, 130 mmHg as the reference), and low levels of postdialysis DBP (<75 mmHg, 80 mmHg as the reference). Threshold effect was determined in the associations between peridialysis BP and all-cause mortality risk, and potential BP thresholds were identified (149 mmHg for predialysis SBP, 79 mmHg for predialysis DBP, 147 mmHg for postdialysis SBP and 76 mmHg for postdialysis DBP). In conclusion, the proposed peridialysis BP ranges and the threshold values could help clinicians identify high risk HD patients. The interpretation of the peridialysis BP mortality associations should be based on the features of HD population (especially the cardiovascular conditions, volume status and the dialysis vintage).

Novel haemodialysis (HD) treatment employing molecular hydrogen (H2)-enriched dialysis solution improves prognosis of chronic dialysis patients: A prospective observational study

Recent studies have revealed unique biological characteristics of molecular hydrogen (H₂) as an anti-inflammatory agent. We developed a novel haemodialysis (E-HD) system delivering an H₂ (30-80 ppb)-enriched dialysis solution by water electrolysis, and conducted a non-randomized, non-blinded, prospective observational study exploring its clinical impact. Prevalent chronic HD patients were allocated to either the E-HD (n = 161) group or the conventional HD (C-HD: n = 148) group, and received the respective HD treatments during the study. The primary endpoint was a composite of all-cause mortality and development of non-lethal cardio-cerebrovascular events (cardiac disease, apoplexy, and leg amputation due to peripheral artery disease). During the 3.28-year mean observation period, there were no differences in dialysis parameters between the two groups; however, post-dialysis hypertension was ameliorated with significant reductions in antihypertensive agents in the E-HD patients. There were 91 events (50 in the C-HD group and 41 in the E-HD group). Multivariate analysis of the Cox proportional hazards model revealed E-HD as an independent significant factor for the primary endpoint (hazard ratio 0.59; [95% confidence interval: 0.38-0.92]) after adjusting for confounding factors (age, cardiovascular disease history, serum albumin, and C-reactive protein). HD applying an H₂-dissolved HD solution could improve the prognosis of chronic HD patients.

Circulating TNF Receptors 1 and 2 Predict Mortality in Patients with End-stage Renal Disease Undergoing Dialysis

Relatively high circulating levels of soluble tumor necrosis factor (TNF) receptors (TNFRs: TNFR1, TNFR2) have been associated with not only progression to end-stage renal disease but also mortality in patients with diabetes. It remains unknown whether elevated TNFR levels in haemodialysis patients are associated with mortality. We studied 319 patients receiving maintenance haemodialysis who were followed for a median of 53 months. Circulating markers of TNF pathway (TNFα and TNFRs) were measured with immunoassay. Strong positive correlations between TNFR1 and TNFR2 were observed (r = 0.81, P < 0.0001). During follow-up, 88 (27.6%) patients died of any cause (40 [45.5%] died of cardiovascular disease). In the Cox multivariate model, either TNFR but not TNFα remained a significant independent predictor of all-cause mortality (TNFR1: hazard ratio [HR] 2.34, 95% confidence interval [CI], 1.50–3.64; TNFR2: HR 2.13, 95% CI 1.38–3.29) after adjustment for age, prior cardiovascular disease, predialysis systolic blood pressure, and large systolic blood pressure decline during dialysis session. For cardiovascular mortality, significance was only observed in TNFR1 (TNFR1: HR 2.15, 95% CI 1.13–4.10). Elevated TNFRs levels were associated with the risk of cardiovascular and/or all-cause mortality independent of all relevant covariates in patients undergoing haemodialysis.

Predialysis hypotension is not a predictor for mortality in long-term hemodialysis patients: insight from a single-center observational study

Introduction

Predialysis hypotension has been noted to be a predictor of mortality in hemodialysis (HD) patients. Previous studies evaluating the impact of predialysis hypotension on the mortality of HD patients did not exclude patients with diabetes mellitus (DM) or cardiovascular disease.

Methods

Eight hundred and sixty-six patients on maintenance HD were recruited. Clinical parameters were recorded and subjected to the analysis of predictors of predialysis hypotension and mortality.

Results

Multivariate logistic regression analyses indicated that DM (odds ratio [OR]: 0.439, P=0.002), hypertension history (OR: 0.634, P=0.022), Kt/V Daugirdas (OR: 2.545, P=0.001), anuria (OR: 2.313, P=0.002), serum phosphate (OR: 0.833, P=0.010), and serum triglyceride (OR: 1.002, P=0.012) were associated with predialysis hypotension. Multivariate Cox regression analysis showed that age (P<0.001), male sex (P=0.029), anuria (P=0.004), and DM (P=0.011) were associated with higher probability of 24- and 36-month mortality. Predialysis hypotension was not associated with higher probability of 12-, 24-, and 36-month mortality.

Conclusion

Predialysis hypotension is not a predictor of 12-, 24-, and 36-month survival in patients without DM and with higher dialysis adequacy.

The Relation Between Variability of Intact Parathyroid Hormone, Calcium, and Cardiac Mortality in Hemodialysis Patients

Chronic kidney disease-mineral and bone disorder (CKD-BMD) is a condition known to be associated with cardiovascular disease and mortality in hemodialysis (HD) patients. The relation between calcium (Ca), phosphorus (P), and intact parathyroid hormone (iPTH) variability in HD patients and cardiac mortality is unknown. The purpose of this study was to assess the relation between variability in these parameters and cardiac mortality. Baseline demographic and biochemical parameters of 218 HD patients together with Ca values corrected with albumin and P values measured on a monthly basis and iPTH levels measured at 3-monthly intervals were recorded over 2 years. Standard deviation (SD) and smoothness index (SI) for each parameter were calculated to assess Ca, P, and iPTH variability. The relations between all parameters and cardiac mortality were then analyzed. Cardiac mortality was observed in 38 patients in the 2-year study period. Nonsurviving patients' ages, systolic and diastolic blood pressure (DBP), high sensitivity C-reactive protein (HsCRP) levels, mean iPTH, and SD iPTH were significantly higher than those of surviving patients, while albumin levels, SI iPTH and SI Ca were significantly lower. Age, low albumin, high DBP, SI iPTH, and SI Ca were identified as independent predictors of cardiac mortality at multivariate analysis. Our study shows that Ca and iPTH variability affect cardiac mortality independently of mean and baseline values. When supported by further studies, the relation between Ca and iPTH variability and cardiac mortality in HD patients can lead to a new perspective in terms of prognosis and treatment planning.

Future Avenues to Decrease Uremic Toxin Concentration

In this article, we review approaches for decreasing uremic solute concentrations in chronic kidney disease and in particular, in end-stage renal disease (ESRD). The rationale to do so is the straightforward relation between concentration and biological (toxic) effect for most toxins. The first section is devoted to extracorporeal strategies (kidney replacement therapy). In the context of high-flux hemodialysis and hemodiafiltration, we discuss increasing dialyzer blood and dialysate flows, frequent and/or extended dialysis, adsorption, bioartificial kidney, and changing physical conditions within the dialyzer (especially for protein-bound toxins). The next section focuses on the intestinal generation of uremic toxins, which in return is stimulated by uremic conditions. Therapeutic options are probiotics, prebiotics, synbiotics, and intestinal sorbents. Current data are conflicting, and these issues need further study before useful therapeutic concepts are developed. The following section is devoted to preservation of (residual) kidney function. Although many therapeutic options may overlap with therapies provided before ESRD, we focus on specific aspects of ESRD treatment, such as the risks of too-strict blood pressure and glycemic regulation and hemodynamic changes during dialysis. Finally, some recommendations are given on how research might be organized with regard to uremic toxins and their effects, removal, and impact on outcomes of uremic patients.