Reverse Epidemiology of Blood Pressure in Peritoneal Dialysis Associated with Dynamic Deterioration of Left Ventricular Function

Resistant and Apparently Resistant Hypertension in Peritoneally Dialyzed Patients

Hypertension in chronic kidney disease patients is very common. The definition of resistant hypertension in the general population is as follows: uncontrolled blood pressure (BP) on three or more hypotensive agents in adequate doses, or when patients are on four or more hypotensive agent categories irrespective of the BP control, with diuretics included in the therapy. However, these resistant hypertension definitions do not apply to the setting of end-stage kidney disease. True resistant hypertension is diagnosed when adherence to treatment and uncontrolled values of BP by ambulatory blood pressure measurement or home blood pressure measurement are confirmed. Due to these limitations, apparent treatment-resistant hypertension (ATRH) is now defined as an uncontrolled blood pressure on three or more antihypertensive medication classes or the introduction and use of four or more medications regardless of blood pressure level. Concerning dialysis patients, data are very limited on hypertension, its epidemiology, and the prevalence of apparent treatment-resistant hypertension in peritoneal dialysis. In this review, therefore, we discuss the hypertension definitions, targets of the therapy in patients on peritoneal dialyses, and their biases and limitations. We present the pathophysiology, diagnosis, and management of high blood pressure in the peritoneally dialyzed population together with published data on the apparent treatment-resistant hypertension prevalence in this population. Peritoneally dialyzed patients represent a unique population of dialyzed subjects; therefore, studies should be conducted on a larger population with a higher quality of drug adherence and target blood pressure values. The definition of resistant hypertension and apparent resistant hypertension in this group should be redefined, which should also consider residual kidney function in relation to both subclinical and clinical endpoints.

Mortality prediction with adaptive feature importance recalibration for peritoneal dialysis patients

The study aims to develop AICare, an interpretable mortality prediction model, using electronic medical records (EMR) from follow-up visits for end-stage renal disease (ESRD) patients. AICare includes a multichannel feature extraction module and an adaptive feature importance recalibration module. It integrates dynamic records and static features to perform personalized health context representation learning. The dataset encompasses 13,091 visits and demographic data of 656 peritoneal dialysis (PD) patients spanning 12 years. An additional public dataset of 4,789 visits from 1,363 hemodialysis (HD) patients is also considered. AICare outperforms traditional deep learning models in mortality prediction while retaining interpretability. It uncovers mortality-feature relationships and variations in feature importance and provides reference values. An AI-doctor interaction system is developed for visualizing patients' health trajectories and risk indicators.

Diagnosis and treatment of hypertension in dialysis patients: a systematic review

In patients with end-stage renal disease (ESRD) undergoing dialysis, hypertension is common but often inadequately controlled. The prevalence of hypertension varies widely among studies because of differences in the definition of hypertension and the methods of used to measure blood pressure (BP), i.e., peri-dialysis or ambulatory BP monitoring (ABPM). Recently, ABPM has become the gold standard for diagnosing hypertension in dialysis patients. Home BP monitoring can also be a good alternative to ABPM, emphasizing BP measurement outside the hemodialysis (HD) unit. One thing for sure is pre- and post-dialysis BP measurements should not be used alone to diagnose and manage hypertension in dialysis patients. The exact target of BP and the relationship between BP and all-cause mortality or cause-specific mortality are unclear in this population. Many observational studies with HD cohorts have almost universally reported a U-shaped or even an L-shaped association between BP and all-cause mortality, but most of these data are based on the BP measured in HD units. Some data with ABPM have shown a linear association between BP and mortality even in HD patients, similar to the general population. Supporting this, the results of meta-analysis have shown a clear benefit of BP reduction in HD patients. Therefore, further research is needed to determine the optimal target BP in the dialysis population, and for now, an individualized approach is appropriate, with particular emphasis on avoiding excessively low BP. Maintaining euvolemia is of paramount importance for BP control in dialysis patients. Patient heterogeneity and the lack of comparative evidence preclude the recommendation of one class of medication over another for all patients. Recently, however, β-blockers could be considered as a first-line therapy in dialysis patients, as they can reduce sympathetic overactivity and left ventricular hypertrophy, which contribute to the high incidence of arrhythmias and sudden cardiac death. Several studies with mineralocorticoid receptor antagonists have also reported promising results in reducing mortality in dialysis patients. However, safety issues such as hyperkalemia or hypotension should be further evaluated before their use.

Is the measurement of tissue advanced glycosylation products by skin autofluorescence associated with mortality in patients treated by peritoneal dialysis?

BACKGROUND

Advanced glycosylated end-products (AGEs) have been shown to cause cardiovascular disease, and tissue AGE accumulation can be measured by skin autofluorescence (SAF). AGEs are cleared by the kidney, and thus accumulate in dialysis patients. However, as the results of SAF measurements in peritoneal dialysis patients (PD) have been ambiguous, we examined the association between mortality and SAF.

METHODS

We reviewed SAF measurements in PD patients attending a university associated PD program, along with standard measurements of dialysis adequacy and peritoneal membrane function.

RESULTS

We studied 341 prevalent PD patients, 61.9% male, mean age 61.2 ± 16 years, and 31.4% of all patients died during a median follow-up of 27.2 (23.3-36.3) months. Patients who died were older, mean age 72 ± 10.5 years, were more often diabetic (60.7%), and had higher median SAF 3.8 (3.2-4.5) AU. On logistic regression, mortality was independently associated with age (odds ratio (OR) 1.1 (95% confidence limits 1.06-1.16), diabetes OR 10.1 (3.1-33.4), SAF OR 3.3 (1.8-6.2), all p < 0.001, and male gender OR 5.2 (1.6-17.4), p = 0.007; and negatively associated with weight OR 0.91 (0.86-0.95), p < 0..001, normalised nitrogen appearance rate (nPNA) OR 0.05 (0.01-0.4), p = 0.005 and mean arterial blood pressure (MAP) OR 0.96 (0.93-0.96), p = 0.03.

CONCLUSIONS

In this observational study, SAF was independently associated with mortality. However, other factors were also associated with mortality, including age, diabetes and malnutrition which have all been reported to affect SAF measurements. Thus, the additional predictive value of measuring SAF compared to standard risk factors for mortality remains to be determined.

Association between subclinical left ventricular ejection fraction and platelet-to-lymphocyte ratio in patients with peritoneal dialysis

Background

Reduced left ventricular ejection function (LVEF) was associated with increased mortality in patients with peritoneal dialysis (PD) in Asia and the United States of America. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were correlated with LVEF in PD. However, little information is available regarding the relationship between monocyte-to-lymphocyte ratio (MLR), left ventricular ejection fraction (LVEF), and the use of NLR, PLR, and MLR in predicting left ventricular systolic dysfunction (LVSD) in patients with PD.

Methods

All 181 patients with PD were enrolled between 2014 and 2021 from the Nephrology Department of the First Affiliated Hospital of the University of South China. Demographic features, clinical characteristics, laboratory values, and echocardiographic parameters were collected.

Results

The mean age of patients with PD was 47.4 ± 12.6, and 90 (49.7%) of the patients were men. LVEF showed a negative correlation with PLR (r = −0.200, p = 0.007) and MLR (r = −0.146, p = 0.049). The levels of NLR, PLR, and MLR were elevated in patients with PD with LVSD compared with those without (all p &lt; 0.05). PLR (OR 4.331, 95% CI: 1.223, 15.342) and albumin (OR 13.346, 95% CI: 3.928, 45.346) were significantly associated with LVSD patients with PD in the multivariate logistic analysis. For differentiating patients with PD with LVSD, optimal cutoffs of NLR, PLR, MLR, and albumin were 4.5 (sensitivity: 76.7%, specificity: 55.0%, and overall accuracy: 58%), 202.6 (sensitivity: 66.7%, specificity: 69.5%, and overall accuracy: 69%), 0.483 (sensitivity: 53.3%, specificity: 72.8%, and overall accuracy: 30%), and 34.6 (sensitivity: 72.2%), respectively.

Conclusions

Our results revealed that PLR was better than NLR, MLR, and albumin in predicting LVSD in PD.

The associations of blood pressure parameters with all-cause and cardiovascular mortality in peritoneal dialysis patients: a cohort study in China

BACKGROUND

It remains controversial to claim blood pressure (BP) as a leading risk factor for high risk of death in peritoneal dialysis patients, and less is known about the relationship between BP and mortality in Chinese peritoneal dialysis patients.

METHODS

From Zhejiang Renal Data System in China, we collected data on patients treated and followed up at 98 peritoneal dialysis centres from 2008 to 2016. The associations of BP parameters [SBP, DBP, mean arterial pressure (MAP) and pulse pressure (PP)] with all-cause and cardiovascular mortality were examined. We fitted Cox models for mortality with penalized splines using nonparametric smoothers. Several sensitivity analyses were performed to confirm the robustness of our primary findings.

RESULTS

A total of 7335 Chinese peritoneal dialysis patients were included. During a median follow-up of 35.8 months, 1281 (17.5%) patients died. SBP, DBP, MAP follow a U-shaped pattern of both all-cause and cardiovascular mortality. PP presents a reverse L-shaped association with all-cause mortality. Either a higher (SBP >141, DBP >85 or MAP >102 mmHg) or lower (SBP <119, DBP <67 or MAP <88 mmHg) BP tends to have a significantly higher all-cause and cardiovascular mortality risk. Higher PP (>60 mmHg) is related to a higher risk of all-cause mortality, but not cardiovascular mortality. These associations remain the same in our competing risk analysis and subgroup analyses.

CONCLUSION

These data indicate U-shaped associations of SBP, DBP and MAP with all-cause mortality and cardiovascular mortality, respectively, and a reverse L-shaped association of PP with all-cause mortality. Further studies are needed to reliably establish the optimal BP targets for better hypertension control in peritoneal dialysis patients.

The Relation of Clinic and Ambulatory BP with the Risk of Cardiovascular Events and All-Cause Mortality among Patients on Peritoneal Dialysis

Large observational studies showed a U-shaped association of clinic blood pressure (BP) with mortality among patients undergoing peritoneal dialysis (PD). Whether ambulatory BP provides a more direct risk signal in this population remains unknown. In a prospective cohort of 108 PD patients, standardized clinic BP was recorded at baseline with the validated device HEM-705 (Omron, Healthcare, Bannockburn, IL, USA) and 24-h ambulatory BP monitoring was performed using the Mobil-O-Graph monitor (IEM, Stolberg, Germany). Over a median follow-up of 16 months (interquartile range: 19 months), 47.2% of the overall population reached the composite outcome of non-fatal myocardial infarction, non-fatal stroke, or all-cause death. In Cox-regression analysis, systolic but not diastolic BP was prognostically informative. Compared with the reference quartile 1 of 24-h systolic BP (SBP), the multivariate-adjusted hazard ratio for the composite outcome was 1.098 (95% confidence interval (CI): 0.434–2.777) in quartile 2, 1.004 (95% CI: 0.382–2.235) in quartile 3 and 2.449 (95% CI: 1.156–5.190) in quartile 4. In contrast, no such association was observed between increasing quartiles of clinic SBP and composite outcome. The present study shows that among PD patients, increasing ambulatory SBP is independently associated with higher risk of adverse cardiovascular events and mortality, providing superior prognostic information than standardized clinic SBP.

Serum Sodium Modifies the Association of Systolic Blood Pressure with Mortality in Peritoneal Dialysis Patients

INTRODUCTION

High serum sodium is associated with increased blood pressure (BP) in dialysis patients, which is a risk factor for cardiovascular (CV) disease. However, the interaction between serum sodium and BP and their association with clinical outcomes in peritoneal dialysis (PD) patients is uncertain.

METHODS

We analyzed a retrospective cohort of 1,656 incident PD patients from January 2006 to December 2013, who were followed up until December 2018. Cox proportional hazards regression models were used to evaluate the association of serum sodium and BP with all-cause and CV mortality. A priori interaction between serum sodium and systolic BP (SBP) was explored, and a subgroup analysis was performed by stratifying SBP into the following 3 groups: <110, 110-130, and >130 mm Hg.

RESULTS

Mean baseline serum sodium was 140.2 ± 3.6 mmol/L, mean SBP was 137 ± 20 mm Hg, and diastolic BP was 85 ± 14 mm Hg. During a median (range) follow-up time of 46.5 (2.6-154.3) months, 507 patients died, 252 of whom died due to CV disease. SBP did not predict all-cause and CV mortality when BP was assessed as a continuous variable. However, SBP >130 or <110 mm Hg was associated with higher risk of all-cause and CV mortality compared with SBP of 110-130 mm Hg. There was a significant interaction between baseline serum sodium and SBP for all-cause mortality (p for interaction = 0.016). In subgroup analysis, among those with SBP >130 mm Hg, the risk of all-cause mortality was elevated in those with serum sodium ≥140 mmol/L (adjusted hazard ratio [aHR] 1.45 [95% confidence interval (CI): 1.07-1.98]), but not for those with serum sodium <140 mmol/L (aHR 1.27 [95% CI: 0.89-1.82]). Conversely, among those with SBP <110 mm Hg, those with serum sodium <140 mmol/L had an elevated risk of mortality (aHR 1.99 [95% CI: 1.31-3.02]), but not those with serum sodium ≥140 mmol/L (aHR 1.15 [95% CI: 0.74-1.79]) (p for interaction = 0.028).

CONCLUSION

The association of BP with mortality was modified by serum sodium levels in PD patients. Further studies are needed to evaluate whether individualized BP control based on serum sodium levels contributes to improve patient outcomes.

Uncertainties in BP management in dialysis patients

Hypertension in dialysis patients is extremely common. In this article, we review the current evidence for blood pressure (BP) goals in hemodialysis patients, and consider the effectiveness of interventions by which BP may be lowered, including manipulation of dietary and dialysate sodium; optimization of extracellular water; prolongation of dialysis time; and antihypertensive medication. Although two meta-analyses suggest lowering BP using antihypertensive drugs might be beneficial in reducing cardiovascular events and mortality, there are insufficient rigorously designed trials in hypertensive hemodialysis populations to determine preferred antihypertensive drug classes. We suggest aiming for predialysis systolic BP between 130 and 159 mm Hg, while at the same time acknowledge the significant limitations of the data upon which it is based. We conclude by summarizing current knowledge as regards management of hypertension in the peritoneal dialysis population and make recommendations for future research in this field.

Volume management as a key dimension of a high-quality PD prescription

BACKGROUND

Appropriate volume control is one of the key goals in a peritoneal dialysis (PD) prescription. As such it is an important component of the International Society of Peritoneal Dialysis (ISPD) guideline for "High-quality PD prescription" necessitating a review of the literature on volume management. The workgroup recognized the importance of including within its scope measures of volume status and blood pressure in prescribing high-quality PD therapy.

METHODS

A Medline and PubMed search for publications addressing volume status and its management in PD since the publication of the 2015 ISPD Adult Cardiovascular and Metabolic Guidelines, from October 2014 through to July 2019, was conducted.

RESULTS

There were no randomized controlled trials on blood pressure intervention and six randomized trials of bioimpedance-guided volume management. Generally, all studies were of small sample size, short duration, and used surrogate markers as primary outcomes. As a consequence, only "practice points" were drawn. High-quality goal-directed PD prescription should aim to achieve and maintain clinical euvolemia taking residual kidney function and its preservation into account, so that both fluid removal from peritoneal ultrafiltration and urine output are considered and residual kidney function is not compromised. Blood pressure should be included as a key objective parameter in assessing the quality of PD prescription but there is currently no evidence for a specific target in PD. Clinical examination remains the keystone of routine clinical care.

CONCLUSIONS

High-quality goal-directed PD prescription should include volume management as one of the key dimensions.

Assessment and Management of Hypertension among Patients on Peritoneal Dialysis

Approximately 7%-10% of patients with ESKD worldwide undergo peritoneal dialysis (PD) as kidney replacement therapy. The continuous nature of this dialytic modality and the absence of acute shifts in pressure and volume parameters is an important differentiation between PD and in-center hemodialysis. However, the burden of hypertension and prognostic association of BP with mortality follow comparable patterns in both modalities. Although management of hypertension uses similar therapeutic principles, long-term preservation of residual diuresis and longevity of peritoneal membrane function require particular attention in the prescription of the appropriate dialysis regimen among those on PD. Dietary sodium restriction, appropriate use of icodextrin, and limited exposure of peritoneal membrane to bioincompatible solutions, as well as adaptation of the PD regimen to the peritoneal transport characteristics, are first-line therapeutic strategies to achieve adequate volume control with a potential long-term benefit on technique survival. Antihypertensive drug therapy is a second-line therapeutic approach, used when BP remains unresponsive to the above volume management strategies. In this article, we review the available evidence on epidemiology, diagnosis, and treatment of hypertension among patients on PD and discuss similarities and differences between PD and in-center hemodialysis. We conclude with a call for randomized trials aiming to elucidate several areas of uncertainty in management of hypertension in the PD population.

The Optimal Blood Pressure Target in Different Dialysis Populations

Hypertension is common and contributes to adverse outcomes in patients undergoing dialysis. However, the proper blood pressure (BP) target remains controversial and several factors make this difficult. This study aimed to investigate the adequate BP target in patients undergoing prevalent dialysis. Data were retrieved from the Clinical Research Center for End-Stage Renal Disease (2009–2014). 2,299 patients undergoing dialysis were evaluated. Patients were assigned into eight groups according to predialysis systolic blood pressure (SBP). The primary outcome was all-cause mortality. During the median follow-up of 4.5 years, a U-shape relation between SBP and mortality was found. The risk of mortality was increased in the SBP <110 and ≥170 mmHg groups. In subgroup analysis, the risk of mortality was similarly shown U-shape with SBP in subjects with no comorbidities, and no use of antihypertensive agents. However, only lowest SBP was a risk factor for mortality in patients with older, having diabetes or coronary artery disease, whereas highest SBP was an only risk factor in younger patients. In respect of dialysis characteristics, patients undergoing hemodialysis showed U-shape between SBP and mortality, while patients undergoing peritoneal dialysis did not. Among hemodialysis patients, patients with shorter dialysis vintage and less interdialytic weight gain showed U-shape association between SBP and mortality. This study showed that the lowest or highest SBP group had higher risk of mortality. Nevertheless, the optimal target BP should be applied according to individual condition of each patient.

Nonparallel Progression of Left Ventricular Structure and Function in Long-Term Peritoneal Dialysis Patients

BACKGROUND/AIMS

Left ventricular hypertrophy and dysfunction are key cardiovascular risk factors of patients on peritoneal dialysis (PD). The purpose of this study was to investigate the dynamic changes of left ventricular (LV) structure and function in patients on long-term PD.

METHODS

Patients who underwent PD catheter insertions from January 2010 to December 2012 in our PD center were enrolled into this study. Cardiac structure and function of those patients were determined by echocardiography (4 times) at 12-month intervals. Patients' biochemical parameters, body mass index, blood pressure, urine output, ultrafiltration, and total fluid removal volume were collected. The use of antihypertensive drugs and active vitamin D₃ was also recorded.

RESULTS

A total of 40 patients were included. After 3 years of follow-up, patients' PD duration time, LV mass/height^2.7 (p = 0.580), interventricular septal thickness (p = 0.216), left ventricular posterior wall thickness (p = 0.216), and LV ejection fraction (p = 0.270) did not show significant changes during the follow-up. In contrast, the E/A ratio (p = 0.004) and e' (p < 0.001) were statistically decreased, and the E/e' ratio (p = 0.006) was increased. Left atrial diameter was increased (p = 0.008), but the changes in left atrial diameter index did not reach statistical significance (p = 0.090).

CONCLUSION

Long-term PD patients maintain stable LV structure and cardiac systolic function, but cardiac diastolic function declines over time.

Overhydration Is a Strong Predictor of Mortality in Peritoneal Dialysis Patients - Independently of Cardiac Failure

Background

Overhydration is a common problem in peritoneal dialysis patients and has been shown to be associated with mortality. However, it still remains unclear whether overhydration per se is predictive of mortality or whether it is mainly a reflection of underlying comorbidities. The purpose of our study was to assess overhydration in peritoneal dialysis patients using bioimpedance spectroscopy and to investigate whether overhydration is an independent predictor of mortality.

Methods

We analyzed and followed 54 peritoneal dialysis patients between June 2008 and December 2014. All patients underwent bioimpedance spectroscopy measurement once and were allocated to normohydrated and overhydrated groups. Overhydration was defined as an absolute overhydration/extracellular volume ratio > 15%. Simultaneously, clinical, echocardiographic and laboratory data were assessed. Heart failure was defined either on echocardiography, as a reduced left ventricular ejection fraction, or clinically according to the New York Heart Association functional classification. Patient survival was documented up until December 31^st 2014. Factors associated with mortality were identified and a multivariable Cox regression model was used to identify independent predictors of mortality.

Results

Apart from higher daily peritoneal ultrafiltration rate and cumulative diuretic dose in overhydrated patients, there were no significant differences between the 2 groups, in particular with respect to gender, body mass index, comorbidity and cardiac medication. Mortality was higher in overhydrated than in euvolemic patients. In the univariate analysis, increased age, overhydration, low diastolic blood pressure, raised troponin and NTproBNP, hypoalbuminemia, heart failure but not CRP were predictive of mortality. After adjustment, only overhydration, increased age and low diastolic blood pressure remained statistically significant in the multivariate analysis.

Conclusions

Overhydration remains an independent predictor of mortality even after adjustment for heart failure in peritoneal dialysis patients and should therefore be actively sought and managed in order to improve survival in this population.