Clinical significance of serum glucose to lymphocyte ratio as a prognostic marker in peritoneal dialysis patients

BACKGROUND

The glucose-to-lymphocyte ratio (GLR), a glucose metabolism and systemic inflammatory response parameter, is associated with an adverse prognosis for various diseases. However, the association between serum GLR and prognosis in patients undergoing peritoneal dialysis (PD) is poorly understood.

METHODS

In this multi-center cohort study, 3236 PD patients were consecutively enrolled between 1 January 2009 and 31 December 2018. Patients were divided into four groups according to the quartiles of baseline GLR levels (Q1: GLR ≤ 2.91, Q2:2.91 < GLR ≤ 3.91, Q3:3.91 < GLR < 5.59 and Q4: GLR ≥ 5.59). The primary endpoint was all-cause and cardiovascular disease (CVD) related mortality. The correlation between GLR and mortality was examined using Kaplan-Meier and multivariable Cox proportional analyses.

RESULTS

During the follow-up period of 45.93 ± 29.01 months, 25.53% (826/3236) patients died, of whom 31% (254/826) were in Q4 (GLR ≥ 5.59). Multivariable analysis revealed that GLR was significantly associated with all-cause mortality (adjusted HR 1.02; CI 1.00 ∼ 1.04, p = .019) and CVD mortality (adjusted HR 1.02; CI 1.00 ∼ 1.04, p = .04). Compared with the Q1 (GLR ≤ 2.91), placement in Q4 was associated with an increased risk of all-cause mortality (adjusted HR: 1.26, 95% CI: 1.02 ∼ 1.56, p = .03) and CVD mortality (adjusted HR 1.76; CI 1.31 ∼ 2.38, p < .001). A nonlinear relationship was found between GLR and all-cause or CVD mortality in patients undergoing PD (p = .032).

CONCLUSION

A higher serum GLR level is an independent prognostic factor for all-cause and CVD mortality in patients undergoing PD, suggesting that more attention should be paid to GLR.

Peritonitis as a risk factor for long-term cardiovascular mortality in peritoneal dialysis patients: The case of a friendly fire?

AIM

Since the impact of peritonitis on long-term non-infectious mortality has not been investigated until the present, the aim of this study was to analyze the impact of peritonitis on long-term cardiovascular (CV) mortality in a large peritoneal dialysis (PD) cohort.

METHODS

The analysis was based on BRAZPD II, a national prospective cohort study that recruited patients in Brazilian centres from December 2004 to January 2011. Incident adult PD patients with at least 90 days on treatment were included in the analysis. Cardiovascular death occurring after a minimum of 30 days after a peritonitis episode was considered the primary endpoint. Cox regression analysis for time-dependent variables was used for the adjustments.

RESULTS

There were 2405 episodes of peritonitis in 5707 patients (48% males, 44% diabetes, 73% hypertensive). Patients with one episode of peritonitis presented a 22% increase in the hazard ratio of late CV mortality compared to those who never experienced peritonitis (HR1.22; CI95%1.01-1.47). Adjusted hazard for CV mortality showed a stepwise negative effect on survival for each additional peritonitis episode of infection: two episodes (HR1.78; CI95%1.31-2.42), three episodes (HR2.81; CI95%1.83-4.32) and four episodes (HR3.84; CI95%2.01-7.32).

CONCLUSION

Peritonitis was an independent predictor of CV mortality and the frequency of peritonitis was strongly associated with an increase in this risk. This is the first study to demonstrate the impact of peritonitis on late cardiovascular mortality of PD patients, suggesting a link between acute inflammation and cardiovascular outcomes.

Oxidative Stress in Patients Undergoing Peritoneal Dialysis: A Current Review of the Literature

Peritoneal dialysis (PD) patients manifest excessive oxidative stress (OS) compared to the general population and predialysis chronic kidney disease patients, mainly due to the composition of the PD solution (high-glucose content, low pH, elevated osmolality, increased lactate concentration and glucose degradation products). However, PD could be considered a more biocompatible form of dialysis compared to hemodialysis (HD), since several studies showed that the latter results in an excess accumulation of oxidative products and loss of antioxidants. OS in PD is tightly linked with chronic inflammation, atherogenesis, peritoneal fibrosis, and loss of residual renal function. Although exogenous supplementation of antioxidants, such as vitamins E and C, N-acetylcysteine, and carotenoids, in some cases showed potential beneficial effects in PD patients, relevant recommendations have not been yet adopted in everyday clinical practice.

Influence of Residual Renal Function in Carotid Modeling as a Marker of Early Atherosclerosis in Dialysis Patients

Atherosclerosis is frequently present in patients with chronic kidney disease (CKD) treated with dialysis. We evaluated the association between residual renal function (RRF), phosphate level, inflammation and other risk factors in carotid modeling as a marker of early atherosclerosis in peritoneal dialysis (PD) compared with hemodialysis (HD) patients. We studied 39 stable PD and 53 HD patients on renal replacement therapy (RRT) for 3 to 36 months duration. B-mode ultrasonography was used to determine carotid artery intima media thickness (CIMT). We classified patients with atherosclerosis if they have CIMT >10 mm and or presence of plaque. Out of our total dialysis population studied of 92 patients, 16.3% were diabetics and 57.6% were on hemodialysis. Expectedly, PD patients had a higher RRF (P < 0.001), 24 h urine volume (P < 0.001); C-reactive protein (P = 0.047), and a lower serum phosphate (P = 0.01), PTH (P < 0.05), alkaline phosphatase (P < 0.05), and albumin levels (P < 0.001) compared to hemodialysis patients. Atherosclerosis was found in 66.3% of patients and in 100% of a diabetic population. There was no significant difference in the presence of atherosclerosis between PD and HD patients [56.4 vs 73.6% HD, respectively]. Multiple regression analysis showed age, diabetes, HD modality, RRF, phosphate, PTH and pulse pressure as independent parameters associated with atherosclerosis. Apart from the traditional risk factors like age and diabetes, our study showed a link of atherosclerosis with metabolic abnormalities secondary to renal failure. We demonstrated a novel, independent association between RRF and atherosclerosis, underlining the importance of preservation of the RRF in dialysis patients.

Linkage of some trace elements, peripheral blood lymphocytes, inflammation, and oxidative stress in patients undergoing either hemodialysis or peritoneal dialysis

BACKGROUND

Changes in essential trace elements may affect the inflammatory and immunological state of patients on hemodialysis (HD) or peritoneal dialysis (PD). Therefore, we aimed to determine trace element content and markers of oxidative stress, inflammation, and immune status in HD and PD patients and to assess the relationships among these parameters.

METHODS

Patients on either HD (n = 20) or PD (n = 20) and age-, sex-, body mass index-matched healthy individuals (n = 20) were enrolled in the study. The trace elements zinc, copper, selenium, and iron; markers of oxidative stress thiobarbituric acid reactive substances (TBARS) and protein carbonyl levels; activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase; percentages of CD3 T lymphocytes and the subsets CD4 and CD8; the CD4/CD8 ratio; and C-reactive protein (CRP) were measured.

RESULTS

All dialysis patients had low levels of albumin and hemoglobin. Significantly decreased percentages of CD3 and CD4 T lymphocytes and increased levels of CRP, TBARS, and carbonyl compounds were observed in HD patients. HD patients also had elevated erythrocyte SOD, lower GPx and catalase activities, and decreased levels of Se, Zn, and Fe in comparison to PD patients and healthy subjects. In addition, CRP was positively associated with TBARS and carbonyl levels, but was significantly inversely associated with Zn and Se levels. Positive correlations were found between T lymphocyte CD3 and CD4 percentages and Zn, Se, and Fe levels.

CONCLUSIONS

There were significant decreases in T lymphocyte-related immunological regulation and increased inflammation and oxidative stress in dialysis patients. Essential trace element status was independently related to immune status, inflammation, and oxidative damage.

Inflammation and oxidative stress in end-stage renal disease patients treated with hemodialysis or peritoneal dialysis

PURPOSE

The impact of different dialysis modalities on oxidative stress and inflammation and the factors implicated in this interrelationship have not been adequately studied. This study was designed to comparatively evaluate the effect of hemodialysis (HD) and peritoneal dialysis (PD) on oxidative stress and inflammatory biomarkers and to search for associated factors.

METHODS

We studied 20 HD, 11 PD patients and 11 healthy controls. Calculations were based on total antioxidant capacity (TAC) and superoxide dismutase (SOD), by spectrophotometry, as oxidative stress biomarkers; and high sensitivity CRP (hs-CRP), Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-alpha), by ELISA, as inflammation biomarkers.

RESULTS

HD and PD patients showed significantly increased levels of TA C, SOD and hs-CRP compared to healthy controls. No significant difference was observed in TNF-alpha and IL-6. Compared to HD patients, PD patients showed TNF-alpha levels that were increased, although non-significantly, and significantly higher homocysteine (Hcy). No differences were observed for IL-6, hs-CRP, TA C and SOD. In HD patients, significant positive correlations were found between intact parathyroid hormone (iPTH) and TNF-alpha, and between uric acid (UA) and TAC. Beta2-microglobulin (Beta2M) was negatively correlated with TAC, total cholesterol (TC) positively with TNF-alpha and negatively with SOD, and triglycerides (TG) correlated positively with TNF-alpha. In PD patients, TG correlated positively with TNF-alpha, HDL-cholesterol negatively with TNF-alpha, LDL-cholesterol negatively with SOD, and Beta2M negatively with SOD.

CONCLUSIONS

HD and PD patients show similar degrees of inflammation and oxidative stress activation. Factors such as UA, iPTH, Beta2M and lipid profile correlate to oxidative stress and inflammatory biomarkers in both HD and PD patients.

Effect of oral N-acetylcysteine treatment on plasma inflammatory and oxidative stress markers in peritoneal dialysis patients: a placebo-controlled study

BACKGROUND

Inflammation and oxidative stress (OS) are cardiovascular risk factors in patients with chronic kidney disease. N-acetylcysteine (NAC) is a thiol-containing antioxidant with anti-inflammatory properties and has been shown to reduce the number of cardiovascular events in hemodialysis patients.

METHODS

The current study aimed to determine the effect of oral NAC (2 x 600 mg/daily) on plasma levels of inflammatory and OS markers in peritoneal dialysis (PD) patients. We performed a placebo-controlled study over 8 weeks in 30 patients (40% males, age 52 +/- 13 years) on regular PD. Before the study was started, the patients were divided into 2 groups of 15 patients matched for age and gender. 22 patients completed the study (12 on NAC, 10 on placebo). Proinflammatory cytokines [high-sensitivity C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-alpha, and pentraxin 3] and markers of OS (pentosidine, advanced oxidation protein products, homocysteine, glutathione, asymmetric dimethylarginine, and free sulfhydryls) were measured before and after treatment with NAC.

RESULTS

Treatment with NAC for 8 weeks increased mean baseline plasma NAC levels from 2.6 to 24.8 mumol/L (p = 0.007). This intervention, which caused no side effects, significantly diminished IL-6 levels, from 9.4 (4.5 - 31) to 7.6 (4.9 - 13.5) pg/mL (p = 0.006), whereas no such changes were observed in the placebo group. NAC treatment did not significantly affect the other inflammatory and OS markers.

CONCLUSION

Short-term oral NAC treatment resulted in reduction of circulating IL-6, suggesting that such treatment could be a useful strategy in blunting the inflammatory response in PD patients.

Applying Translational Research in Understanding Complications and Defining Targets for Intervention: Inflammation in PD as a Model

The bench-to-bedside approach to translational research is becoming increasingly important to efficiently advance understanding of the mechanisms underlying disease and to improve the quality of patient care. Although this investigation model has been practiced since the early days of the therapy, robust research platforms built to practice translational research have only recently been structured in the field of peritoneal dialysis. Experience with a translational research environment that generated most of the information cited in this overview is the core of this manuscript. The central investigation theme described is how to approach the cardiovascular complications of peritoneal dialysis. The research question was, could the continuous activation of inflammatory pathways be central in this process and represent a relevant target for interventions?