Can we reduce the cardiovascular risk in peritoneal dialysis patients?

Serum Lipoprotein(a) Levels as a Predictor of Aortic Stiffness in Patients on Long-Term Peritoneal Dialysis

BACKGROUND Lipoprotein (a) [Lp(a)] is associated with atherosclerosis and cardiovascular mortality in patients with kidney failure. Aortic stiffness (AS), measured primarily by carotid-femoral pulse wave velocity (cfPWV), reflects vascular aging and precedes end-organ failure. This study aimed to evaluate the association between serum Lp(a) levels and cfPWV in patients undergoing peritoneal dialysis (PD). MATERIAL AND METHODS In this cross-sectional study, which included 148 patients with long-term PD for end-stage kidney failure, cfPWV was measured using a cuff-based method. AS was defined as a cfPWV exceeding 10 m/s, and an enzyme-linked immunosorbent assay was used to determine serum Lp(a) levels. Univariate and multivariate regression analyses were performed to identify the clinical correlates of AS. RESULTS There were 32 (21.6%) patients diagnosed with AS. Based on the multivariate logistic regression analysis, the odds ratio for AS was 1.007 (95% confidence interval, 1.003-1.011; P=0.001) for every 1 mg/L increase in Lp(a) levels. Multivariate linear regression analysis showed that Lp(a) (P<0.001), age (P=0.003), waist circumference (P=0.008), systolic blood pressure (P=0.010), and diabetes mellitus (P<0.001) were positively associated with cfPWV. The area under the receiver operating characteristic curve for Lp(a) in differentiating AS from non-AS was 0.770 (95% confidence interval, 0.694-0.835; P<0.0001). CONCLUSIONS Serum Lp(a) level was independently associated with cfPWV and AS in patients with PD.

Improvement of clinical outcomes in patients undergoing peritoneal dialysis using hydroxymethylglutaryl-CoA reductase inhibitors: A systematic review and meta-analysis

BACKGROUND

It is unclear whether hydroxymethylglutaryl-CoA reductase inhibitor (statin) therapy decreases the risk of mortality and cardiovascular disease (CVD) in patients undergoing peritoneal dialysis (PD).

METHODS

We performed a literature search of PubMed, Cochrane Library, Embase, and other databases for research publications up to June 2022. The outcomes of interest were fatal and nonfatal CVDs, all-cause mortality, and changes in the biochemical profiles. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled and synthesized using a random-effects model. The certainty of the evidence was determined using Grading of Recommendations, Assessment, Development, and Evaluation.

RESULTS

Nine studies, including 2,933 patients undergoing PD, were included. Among them, three studies, including 2,099 patients, reported all-cause mortality, and three, including 1,571 patients, reported CVDs. In these patients, pooling results of two observational studies (very low-certainty evidence) showed that statin therapy significantly reduced CVDs (HR = 0.67; 95% CI = 0.54-0.84; p = 0.0004). Moreover, statin therapy was associated with significantly reduced low-density lipoprotein cholesterol, total cholesterol, and C-reactive protein levels (very low certainty of evidence). However, the effects of statin therapy on triglyceride, high-density lipoprotein, and albumin levels were not statistically significant.

CONCLUSION

Although statin therapy was associated with significantly reduced low-density lipoprotein cholesterol, total cholesterol, and C-reactive protein levels, the probable beneficial effect of statins on CVD risk in patients undergoing PD could not be concluded firmly. Additional high-quality studies are required to assess the potential beneficial effects of statin therapy in PD patients.

Nutritional and Hydration Status and Adherence to Dietary Recommendations in Dalmatian Dialysis Patients

Protein-energy wasting (PEW) is considered one of the major complications of chronic kidney disease (CKD), particularly in dialysis patients. Insufficient energy and protein intake, together with clinical complications, may contribute to the onset and severity of PEW. Therefore, the aim of the study was to analyze the differences in nutritional and hydration status and dietary intake among Dalmatian dialysis patients. Fifty-five hemodialysis (HD) and twenty peritoneal dialysis (PD) participants were included. For each study participant, data about body composition, anthropometric, laboratory, and clinical parameters were obtained. The Malnutrition Inflammation Score (MIS) and two separate 24-h dietary recalls were used to assess nutritional status and dietary intake. The Nutrient Adequacy Ratio (NAR) and Mean Adequacy Ratio (MAR) were calculated to compare actual dietary intake with recommended intake. Additionally, the estimated 10-year survival was calculated using the Charlson Comorbidity Index. The prevalence of malnutrition according to MIS was 47.3% in HD and 45% in PD participants. Significant differences in fat tissue parameters were found between HD and PD participants, whereas significant differences in hydration status and muscle mass parameters were not found. A significant difference in NAR between HD and PD participants was noticed for potassium and phosphorus intake, but not for MAR. MIS correlated negatively with anthropometric parameters, fat mass, visceral fat level and trunk fat mass, and iron and uric acid in HD participants, whereas no significant correlations were found in PD participants. The estimated 10-year survival correlated with several parameters of nutritional status in HD and PD participants, as well as nutrient intake in HD participants. These results indicate a high prevalence of malnutrition and inadequate dietary intake in the Dalmatian dialysis population which, furthermore, highlights the urgent need for individualized and structural nutritional support.

Dyslipidemia and Intraperitoneal Inflammation Axis in Peritoneal Dialysis Patients: A Cross-Sectional Pilot Study

Background

We have hypothesized that the problem of dyslipidemia in peritoneal dialysis (PD) patients lies beyond certain levels of plasma lipoprotein and involves cardiovascular risk, but can also influence the development of chronic intraperitoneal inflammation.

Objectives

The aim of our work was to define whether the association of dyslipidemia with intraperitoneal inflammation really exists and if it could it be used in a prospective cohort of PD patients.

Patients and Methods

We performed a cross-sectional, single-center, pilot study involving 40 nondiabetic PD patients (27 men and 13 women with an average age of 49.3 ± 12.2 years). The median time on PD was 29 (18.5-37) months. The parameters dialysis adequacy, blood lipid profile, and the concentrations of tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and interleukin (IL)-10 in peritoneal dialysate effluent (PDE) were determined. Cohen's d effect size was computed post hoc to determine the differences between groups in the concentrations of pro- and anti-inflammatory mediators.

Results

PD patients with atherogenic dyslipidemia had significantly high levels of MCP-1 compared with dyslipidemia-free patients (Cohen's d = 1.32). A reduced high-density lipoprotein cholesterol level was associated with a high intraperitoneal production of the proinflammatory mediator TNF-α (p < 0.0001) and anti-inflammatory IL-10 (p < 0.0001). Atherogenic index of plasma was directly correlated with MCP-1 (p < 0.0001) and TNF-α (p < 0.0001). In multiple regression analysis, MCP-1 appeared to predict PD inadequacy (R ² = 0.58; F ratio = 9.4; p = 0.006) independently of age and blood C-reactive protein level. Effect size was 1.38 with α = 0.05, n = 40, and 3 predictors.

Conclusions

Our cross-sectional pilot study first demonstrated a close interaction between the atherogenic lipid profile and a high concentration of MCP-1 in PDE; this might be a prognostic marker for PD inadequacy. The potential significance of our finding is that it provides useful preliminary information necessary for further research into this area.

Association between Dyslipidemia and Peritoneal Dialysis Technique Survival

BACKGROUND:

A large body of research has investigated the effects of pro-atherogenic lipid profile on cardiovascular diseases (CVD) in peritoneal dialysis (PD) patients. However, there is a general lack of research on the association between atherogenic dyslipidemia and PD technique survival.

AIM:

The study aimed to define the association between dyslipidemia and PD technique survival.

METHODS:

It was a prospective single-centre observational study involving 40 outpatients on continuous ambulatory PD treatment for more than 3 months between 2010 and 2016 in a single centre in Ukraine. There were 27 males and 13 females. The mean age of the participants was 49.3 ± 12.2 years. The primary outcome measures were all-cause technique failure.

RESULTS:

Atherogenic dyslipidemia was identified in 28/40 (70 %) patients and correlated with PD adequacy parameters. During the 36-month- follow-up period technique failure occurred in 2/12 (16.6 %) patients with atherogenic dyslipidemia compared with 12 / 28 (42.9 %) patients without atherogenic dyslipidemia (χ² = 2.5; p = 0.12). In the univariate Cox regression model, atherogenic dyslipidemia at baseline was significantly associated with a higher risk of all-cause PD technique failure (HR 4.5; 95% CI 1.6 to 12.9; χ² = 5.5, p = 0.019).

CONCLUSION:

The presence of atherogenic dyslipidemia was significantly associated with a higher risk of technique failure in PD patients. This is an important issue for future research. Further well-designed clinical trials are needed to determine the impact of dyslipidemia on PD adequacy and technique survival.

Expanded peripheral CD4+CD28null T cells and its association with atherosclerotic changes in patients with end stage renal disease on hemodialysis

End-stage renal disease (ESRD) patients, including those on hemodialysis, possess a high risk for cardiovascular diseases, as the first leading cause of death among them. Traditional risk factors do not utterly elucidate this. Throughout the last two decades, CD4⁺CD28^null T cells; an unusual subset of T lymphocytes, was detected high with excess cardiovascular (CV) mortality. We aimed to investigate the circulating CD4⁺CD28^null T cells frequency in ESRD patients on hemodialysis and to evaluate their relationship with atherosclerotic changes. High-resolution carotid ultrasonography was done to assess the common carotid artery intima media thickness in a number of ESRD patients, accordingly patients were selected and subdivided into two groups; 30 with atherosclerosis (mean [SD] age, 51.6 [6.3] years) and 30 without (mean [SD] age, 48.9 [5.5] years). Another 30 healthy individuals (mean [SD] age, 48.5 [6.8] years) were enrolled. Analysis of CD4⁺CD28^null T-cells frequency by flow-cytometry was performed in all studied subjects. CD4⁺CD28^null T cell percentage was significantly higher in ESRD patients, (mean [SD], 7.3 [2.7] %) compared to healthy individuals (mean [SD], 3.0 [0.8] %), (p < 0.001). Additionally, the expansion of these unusual T lymphocytes was significantly higher in ESRD patients with atherosclerotic changes (mean [SD], 9.47 [0.75] %) compared to those without atherosclerosis (mean [SD], 5.22 [2.14] %), (p < 0.001). In conclusion circulating CD4⁺CD28^null T lymphocyte population showed expansion in ESRD patients, and of interest in correlation to preclinical atherosclerotic changes.

Higher serum triglyceride to high-density lipoprotein cholesterol ratio was associated with increased cardiovascular mortality in female patients on peritoneal dialysis

BACKGROUND AND AIMS

High serum triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio has been found to be an independent predictor for cardiovascular events in the general population. We aimed to evaluate whether a high TG/HDL-C ratio was associated with an increased risk of mortality in patients on continuous ambulatory peritoneal dialysis (CAPD).

METHODS AND RESULTS

In this single-center retrospective cohort study, 1170 incident patients on peritoneal dialysis (PD) from 1 January 2007 to 31 December 2011 were recruited and followed up until 31 December 31 2013. The mean age was 47.4 ± 15.2 years, and 24.7% were diabetic. During a median of the 34.5-month follow-up period, 213 (18.2%) deaths occurred, 121 of which (56.8%) were caused by cardiovascular disease (CVD). The serum median TG/HDL-C ratio at baseline was 2.57 (range: 0.06-39.39). On multivariate Cox regression analysis, the highest quartile of the TG/HDL-C ratio (≥4.19) was associated with increased risk of all-cause mortality (hazard ratio (HR) 1.98, 95% confidence interval (CI), 1.17-3.36; P = 0.011) and CVD mortality (HR 2.28, 95% CI, 1.16-4.47; P = 0.017). For female patients, each one-unit higher baseline TG/HDL-C was associated with 13% (95% CI 1.06-1.22; P = 0.001) increased risk of CVD mortality, whereas such an association was not observed for male patients, (HR 1.00, 95% CI 0.92-1.08; P = 0.977).

CONCLUSIONS

A higher serum TG/HDL-C ratio was associated with an increased risk of all-cause and CVD mortality in PD patients. Moreover, the increased risk of CVD mortality was significantly higher in female than male PD patients.

Predictors of left ventricular hypertrophy and their cutoffs in peritoneal dialysis patients

Cardiovascular complications are the main cause of morbidity and mortality in peritoneal dialysis (PD) patients. Left ventricular hypertrophy (LVH) is a major predictor of the development of cardiovascular events. This study aimed to identify risk factors that contribute to the development of LVH and to determine their cutoffs in patients on maintenance peritoneal dialysis.In this cross sectional study we evaluated the association of 23 variables including age, PD vintage, ultrafiltration, urine volume, residual renal function, mean daily SBP, mean daily DBP, fasting glucose, HbA1c, peritoneal glucose load index (PGLI), fluid overload (FO), plasma brain natriuretic peptide (BNP), plasma hsCRP and IL-6, serum albumin, white blood cell (WBC) count, hemoglobin, hematocrit, triglycerides, LDL-C (low density lipoprotein cholesterol), HDL-C (high density lipoprotein cholesterol), and PTH with LVH in 38 stable patients on maintenance PD ≥ 24 months.LVH was detected in 57.9% of patients. Logistic regression and receiver operating characteristics (ROC) analysis revealed that HbA1c, PGLI, FO, plasma BNP, hsCRP and IL-6 seem to be possible predictors of LVH. The cutoffs associated with the presence of LVH were: 7.5%, 3.2 g/kg/day, 1.7 L, 330 pg/mL, 7.5 mg/dL and 3.3 pg/mL for HbA1c, PGLI, FO, plasma BNP, hsCRP and IL-6, respectively (sensitivity 72.8 to 81.8% and specificity 75.0 to 93.8%).The results suggest that efforts should be made to reduce the peritoneal glucose load (PGL), to improve the hydration status, and to attenuate the inflammatory process in order to reduce the risk of the development of LVH among PD patients.

Associations between the duration of dialysis, endotoxemia, monocyte chemoattractant protein-1, and the effects of a short-dwell exchange in patients requiring continuous ambulatory peritoneal dialysis

Background

Endotoxemia is exaggerated and contributes to systemic inflammation and atherosclerosis in patients requiring continuous ambulatory peritoneal dialysis (CAPD). The risk of mortality is substantially increased in patients requiring CAPD for >2 years. However, little is known about the effects of long-term CAPD on circulating endotoxin and cytokine levels. Therefore, the present study evaluated the associations between plasma endotoxin levels, cytokine levels, and clinical parameters with the effects of a short-dwell exchange on endotoxemia and cytokine levels in patients on long-term CAPD.

Methods

A total of 26 patients were enrolled and divided into two groups (short-term or long-term CAPD) according to the 2-year duration of CAPD. Plasma endotoxin and cytokine levels were measured before and after a short-dwell exchange (4-h dwell) during a peritoneal equilibration test (a standardized method to evaluate the solute transport function of peritoneal membrane). These data were analyzed to determine the relationship of circulating endotoxemia, cytokines and clinical characteristics between the two groups.

Results

Plasma endotoxin and monocyte chemotactic protein-1 (MCP-1) levels were significantly elevated in the long-term group. PD duration was significantly correlated with plasma endotoxin (r = 0.479, P = 0.016) and MCP-1 (r = 0.486, P = 0.012). PD duration was also independently associated with plasma MCP-1 levels in multivariate regression. Plasma MCP-1 levels tended to decrease (13.3% reduction, P = 0.077) though endotoxin levels did not decrease in the long-term PD group after the 4-h short-dwell exchange.

Conclusion

Long-term PD may result in exaggerated endotoxemia and elevated plasma MCP-1 levels. The duration of PD was significantly correlated with circulating endotoxin and MCP-1 levels, and was an independent predictor of plasma MCP-1 levels. Short-dwell exchange seemed to have favorable effects on circulating MCP-1 levels in patients on long-term PD.

Comparative mortality-predictability using alkaline phosphatase and parathyroid hormone in patients on peritoneal dialysis and hemodialysis

BACKGROUND

In hemodialysis (HD) patients, serum alkaline phosphatase (ALP) and parathyroid hormone (PTH) derangements are associated with mortality, but outcome-predictability using ALP and PTH in peritoneal dialysis (PD) patients remains uncertain.

METHODS

In a cohort of 9244 adult PD patients from a large national dialysis organization (entry period 2001 - 2006, with follow-up through 2009), we used multivariable Cox models adjusted for case-mix and laboratory covariates to examine the associations of time-averaged ALP and PTH with all-cause mortality. We then compared mortality-predictability using ALP and PTH in 9244 PD and 99 323 HD patients.

RESULTS

In PD patients, ALP concentrations exceeding 150 U/L were associated with increased mortality (reference ALP: 70 to <90 U/L). Hazard ratios (HRs) and 95% confidence intervals (CIs) were 1.18 (1.03 to 1.36), 1.27 (1.08 to 1.50), 1.49 (1.23 to 1.79), and 1.35 (1.19 to 1.53) for ALP concentrations of 150 to <170 U/L, 170 to <190 U/L, 190 to <210 U/L, and ≥210 U/L respectively. In contrast, we observed a U-shaped association between PTH concentration and death risk in PD patients, with PTH concentrations of less than 200 pg/mL and 700 pg/mL or more associated with increased mortality (reference PTH: 200 to <300 pg/mL). Hazard ratios and 95% CIs were 1.25 (1.12 to 1.41), 1.12 (1.02 to 1.23), 1.06 (0.96 to 1.18), 1.09 (0.97 to 1.24), 1.12 (0.97 to 1.29), 1.18 (0.99 to 1.40), and 1.23 (1.09 to 1.38) for PTH concentrations of <100 pg/mL, 100 to <200 pg/mL, 300 to <400 pg/mL, 400 to <500 pg/mL, 500 to <600 pg/mL, 600 to <700 pg/mL, and ≥700 pg/mL respectively. Compared with PD patients having serum concentrations of ALP and PTH within reference ranges, patients on HD experienced increased mortality across all ALP and PTH concentrations, particularly those in the lowest and highest categories.

CONCLUSIONS

In summary, higher ALP concentrations are associated with increased mortality, and lower and higher PTH concentrations are both associated with death risk in PD patients. The utility of ALP in the management of chronic kidney disease mineral bone disorders in PD patients warrants further study.

Associations between bioelectrical impedance parameters and cardiovascular events in chronic dialysis patients

PURPOSE

Malnutrition and fluid overload contribute to the poor cardiovascular prognosis of dialysis patients. Since bioelectrical impedance analysis is an option for the evaluation of body composition and for the monitoring of hydration state, it may assist in the identification of subjects at high cardiovascular risk. The objective of this study was to evaluate the association between bioelectrical impedance parameters and cardiovascular events.

METHODS

The association between bioelectrical impedance parameters and fatal and non-fatal cardiovascular outcome was evaluated in 145 dialysis patients.

RESULTS

The mean age of the population studied was 54.9 ± 15.4 years, 49.7 % were males, and 35.9 % had diabetes. Forty (27.6 %) patients developed cardiovascular events during the 16 months (8; 32) of follow-up. Comparison of patients with and without cardiovascular events revealed higher extracellular mass/body cell mass (ECM/BCM) and extracellular water/total body water ratios and higher C-reactive protein levels in the former. Survival analysis showed that an ECM/BCM ratio >1.2 and a phase angle <6° were associated with poor cardiovascular prognosis. Among nondiabetic patients, these parameters and capacitance were independently associated with cardiovascular events, suggesting that poor nutritional status and fluid overload are associated with the occurrence of these events.

CONCLUSIONS

Phase angle, capacitance and ECM/BCM ratio are valuable parameters for the evaluation of cardiovascular prognosis, supporting the use of bioelectrical impedance for the clinical assessment of dialysis patients.

Peritoneal dialysis in diabetics: there is room for more

End stage renal disease diabetic patients suffer from worse clinical outcomes under dialysis-independently of modality. Peritoneal dialysis offers them the advantages of home therapy while sparing their frail vascular capital and preserving residual renal function. Other benefits and potential risks deserve discussion. Predialysis intervention with early nephrology referral, patient education, and multidisciplinary support are recommended. Skilled and updated peritoneal dialysis protocols must be prescribed to assure better survival. Optimized volume control, glucose-sparing peritoneal dialysis regimens, and elective use of icodextrin are key therapy strategies. Nutritional evaluation and support, preferential use of low-glucose degradation products solutions, and prescription of renin-angiotensin-aldosterone system acting drugs should also be part of the panel to improve diabetic care under peritoneal dialysis.

Plasma fatty acid composition in continuous ambulatory peritoneal dialysis patients: an increased omega-6/omega-3 ratio and deficiency of essential fatty acids

Patients with end-stage renal disease, including those treated with peritoneal dialysis, have a high risk for death, particularly from cardiovascular causes. Plasma fatty acid (FA) composition is used as an indicator of disease risk, because its alteration has been related to metabolic disease and cardiovascular disease. For this purpose, we have measured plasma FA composition in continuous ambulatory peritoneal dialysis (CAPD) patients and compared them with those of healthy subjects. This study was performed on 51 (21 M, 30 F) CAPD patients at least 6 months under dialysis, aged 20-75 years (mean 47.81 ± 11.8 years) and 45 (25 M, 20 F) healthy control subjects aged 20-60 years (mean 38.62 ± 12.9 years). Plasma 10-cis-pentadecanoic acid, 10-cis-heptadecanoic acid, heneicosanoic acid, tricosanoic acid, nervonic acid, saturated fatty acid, and monounsaturated FA levels and delta 9 desaturase activity were significantly higher whereas linoleic acid, linolenic acid, 11,14-eicosedienoic acid, arachidonic acid, docosahexaenoic acid, and omega-3 FA levels were significantly lower in the CAPD group than those in the healthy group. Our results show that there are FA abnormalities and especially a depletion in essential FA levels and a high level of omega-6/omega-3 ratio in CAPD patients, the underlying mechanism of which is not known and needs to be investigated. Therefore, we believe that essential FA supplementation should be encouraged for CAPD patients.

CD4+CD28null cells are expanded and exhibit a cytolytic profile in end-stage renal disease patients on peritoneal dialysis

BACKGROUND

End-stage renal failure patients, including those on peritoneal dialysis (PD), exhibit several nontraditional cardiovascular (CV) risk factors. A role of CD4(+)CD28(null) T lymphocytes in the genesis of coronary artery disease (CAD) has been proposed. We investigated this cell population and examined its phenotype in a cohort of PD patients without CV disease.

METHODS

The frequency of the peripheral blood CD4(+)CD28(null) T-cell compartment and cytotoxic characteristic of these cells (as assessed by perforin and granzyme B expressions) were determined in 33 PD patients without CAD and 20 healthy subjects by two- and three-color flowcytometry. High-sensitivity C-reactive protein (hs-CRP) was determined by enzyme-linked immunosorbent assay. We investigated whether there was a correlation between these cells and traditional CV risk factors.

RESULTS

Compared to healthy controls, CD4(+)CD28(null) T cells were significantly expanded in PD patients (10.30 ± 2.03% versus 3.55 ± 0.67%, mean ± SE, P = 0.0007). Perforin and granzyme B expressions were restricted to CD4(+)CD28(null) T cells compared to CD4(+)CD28(+) T cells (<0.0001). A greater proportion of CD4(+)CD28(null) T cells in PD patients expressed these molecules (P = 0.007 and 0.04). hs-CRP level was increased in PD patients (P < 0.0001) but did not correlate with the CD4(+)CD28(null) T-cell frequency. Increasing age correlated with the CD4(+)CD28(null) cells.

CONCLUSIONS

PD patients exhibit a substantially increased number of circulating CD4(+)CD28(null) T cells that show a cytolytic profile before the onset of clinically significant CAD. Their significance as a nontraditional CV risk factor needs further studies.