Peritoneal dialysis in diabetic patients

Increased Access, Persistent Disparities: Trends in Disparities in Peritoneal Dialysis (PD) Use, 2009-2019

Peritoneal dialysis (PD) use has increased in the United States since 2009, but how this has affected disparities in PD use is unclear. We used data from the United States Renal Data System to identify a cohort of incident dialysis patients from 2009 to 2019. We used logistic regression models to examine how odds of PD use changed by demographic characteristics. The incident PD population increased by 203% from 2009 to 2019, and the odds of PD use increased in every subgroup. PD use increased more among older people because the odds for those aged 75 years or older increased 15% more per 5-year period compared with individuals aged 18-44 years (odds ratio [OR] 1.68, 95% confidence interval [CI], 1.64 to 1.73 versus OR 1.46, 95% CI, 1.42 to 1.50). The odds of PD use increased 5% more per 5-year period among Hispanic people compared with White people (OR 1.58, 95% CI, 1.53 to 1.63 versus OR 1.51, 95% CI, 1.48 to 1.53). There was no difference in odds of PD initiation among people who were Black, Asian, or of another race. The odds of PD use increased 5% more for people living in urban areas compared with people living in nonurban areas (5-year OR 1.54, 95% CI, 1.52 to 1.56 versus 5-year OR 1.46, 95% CI, 1.42 to 1.50). The odds of PD use increased 7% more for people living in socioeconomically advantaged areas compared with people living in more deprived areas (5-year OR 1.60, 95% CI, 1.56 to 1.63 for neighborhoods with lowest Social Deprivation Index versus 5-year OR 1.50, 95% CI, 1.48 to 1.53 in the most deprived areas). Expansion of PD use led to a reduction in disparities for older people and for Hispanic people. Although PD use increased across all strata of socioeconomic deprivation, the gap in PD use between people living in the least deprived areas and those living in the most deprived areas widened.

Long-Term Clinical Outcomes of Peritoneal Dialysis Patients: Single Center Experience from Korea

Of a large body of literature reporting clinical outcomes for patients maintained on peritoneal dialysis (PD), most publications have focused on relatively short-term results. Few reports have focused on long-term survival in PD patients. Here, we present our experience with long-term patient outcomes and further analyses of the trends in demographics and clinical outcomes of 2301 end-stage renal disease (ESRD) patients treated with continuous ambulatory PD (CAPD) during a 25-year period (1981 – 2005) at our institute. Outcomes were analyzed for 1656 patients, excluding those younger than 15 years of age at initiation of CAPD, those having less than 3 months’ follow-up, or those who had been on hemodialysis or who received a kidney graft before starting CAPD.

In the study patients, technique survival at 5 and 10 years was 71.9% and 48.1% respectively. Patient survival was 69.8% and 51.8%. Mean age at the start of PD (50.4 ± 13.9 years vs. 44.2 ± 13.9 years, p < 0.01), ESRD incidence as a result of diabetic nephropathy (30.5% vs. 19.5%, p < 0.01), and incidence of cardiovascular comorbidities (26.6% vs. 20.5%, p < 0.01) were all significantly greater in patients who started PD during the second half of the study period (1993 – 2005) as compared with the first half (1981 – 1992). A multivariate analysis adjusting for these changes in demographics and comorbid conditions revealed that PD therapy starting in 1993 – 2005 was associated with a significant reduction in technique failure [hazard ratio (HR): 0.65; p < 0.01] and mortality (HR: 0.68; p < 0.01) as compared with the earlier period. However, in subgroup analyses, technique survival was not observed to be significantly improved in patients with diabetes.

In summary, technique and patient survival have significantly improved despite increases in patient age, cardiovascular comorbidity, and ESRD caused by diabetes. Although diabetes, older age, and cardiovascular comorbidities are not factors that are easily modifiable to improve PD outcomes, results at our institution are encouraging in an era of declining PD utilization.

The Fate of Older Diabetic Patients on Peritoneal Dialysis: Myths and Mysteries and Suggestions for Further Research

The outcome of older and especially of female diabetic patients appears to be worse on peritoneal dialysis (PD) than on hemodialysis (HD). This opinion is based mostly on data coming from the USA, whereas data from other regions seem to give a more balanced picture. The questions arise whether indeed outcome is worse in this patient group, and what might be the underlying reasons for this; further research to unravel this phenomenon is warranted. This review proposes several suggestions for further exploration. The observed differences in outcome might be attributable to differences in treatment practices and experience with PD versus HD. As cardiovascular mortality is a major killer in end-stage renal disease patients, differences in fluid homeostasis and how it is achieved are potential explanations. Fluid balance is potentially more difficult to obtain in PD patients, especially as in the past it was spuriously suggested that fluid restriction was less important in PD patients. PD and HD might also have different impacts on factors related to inflammation, insulin resistance, and hormone balance. The adipocytokine network is of special interest in this respect. It is also possible that bias introduced by the way we measure body composition might have a more negative impact on PD than on HD patients. Finally, it still is not fully established that if diabetic patients are treated appropriately, their outcome on PD is worse than that on HD; further observational trials in this respect are needed. All these topics require further clarification and investigation.

Negotiated Care Improves Fluid Status in Diabetic Peritoneal Dialysis Patients

Background

Volume overload is common in diabetic patients on continuous ambulatory peritoneal dialysis (PD), especially when the patient's residual renal function decreases with time on PD. Due to the higher dietary salt and fluid intake, diabetic PD patients tend to use more hyper-tonic glucose solution to remove excess fluid, which in turn may lead to increased membrane permeability. In the present study, we investigated the effect of negotiated care on fluid status in diabetic PD patients.

Methods

All diabetic PD patients who had been on PD for at least 3 months by the end of year 2002 in the First Hospital of Peking University were included in the present study. A primary nurse was assigned to each patient and intensive patient education was implemented, focusing on the importance of dietary salt and fluid restriction, the detrimental effect of using more hypertonic glucose solution, and the consequence of fluid overload. Decisions on dialysis prescriptions were made after extensive discussion among the primary nurse, nephrologists, patients, and patients’ families. A patient support group was also involved when it was necessary. All the patients were followed for 1 year and fluid status, compliance to dietary restriction, and dialysis prescription were evaluated before the start and at the end of the study.

Results

There were 30 diabetic PD patients (age 65.4 ± 10.3 years; on PD for 24.5 ± 19.9 months, range 3 – 66 months) included in the study when it was started. During the 1 year of follow-up, 4 patients died of diabetic complications, 3 patients were transferred to hemodialysis due to resistant peritonitis, and 2 patients were transplanted. By the end of follow-up, 21 patients remained on PD, among whom 15 had improved fluid status, 4 did not change, and 2 had worsened fluid status as assessed by clinical and bio-impedance evaluation. Patient compliance to dietary salt and fluid restriction had increased from 19.5% to 76.2%. During the follow-up, 8 patients were anuric at the beginning of the study and the remaining 22 patients had declining residual renal function. Only 4 patients increased their use of hypertonic solution including 2.5% (3 patients) and 4.25% (1 patient) glucose, whereas 5 patients decreased their use of 2.5% dialysis solution. By the end of follow-up, only 1 of the 21 patients was using 4.25% glucose solution and all the patients had good blood glucose control.

Conclusions

Our results suggest that negotiated care can be successfully used in diabetic PD patients. It helps to minimize the use of hypertonic glucose solution and improves patient compliance to dietary restriction of salt and fluid intake, and thus improves their fluid status.

Improving Outcome of Capd: Twenty-Five Years’ Experience in a Single Korean Center

Background

Continuous ambulatory peritoneal dialysis (CAPD) is an established treatment for end-stage renal disease (ESRD). We investigated the outcome of CAPD over a period of 25 years at our institution.

Methods

CAPD has been performed in 2301 patients in 25 years. After excluding patients with less than 3 months of follow-up and missing data, we evaluated 1656 patients who started peritoneal dialysis between November 1981 and December 2005. Data for sex, age, primary disease, co-morbidities, follow-up duration, cause of death, and cause of technique failure were collected. We also examined data for urea kinetic modeling (UKM), beginning in 1990, and peritonitis episodes, including causative organisms, starting in 1992.

Results

Compared to incident patients from 1981 – 1992, mean age and incidence of ESRD caused by diabetic nephropathy increased in patients from 1993 to 2005. Technique survival after 5 and 10 years was 71.9% and 48.1% respectively. Technique survival was significantly higher in patients who started CAPD after 1992 than in those who started before 1992. Peritonitis was the main reason for technique failure. Overall peritonitis rate was 0.38 episodes per patient-year, with a significant downward trend to 0.29 per patient-year over 10 years, corresponding to a decrease in gram-positive peritonitis. Patient survival after 5 and 10 years was 69.8% and 51.8% respectively. Patient survival improved significantly during 1992 – 2005 compared to 1981 – 1992 after adjustment for age, gender, diabetes, and cardiovascular comorbidities [hazard ratio (HR) 0.68, p < 0.01]. Subgroup analysis based on UKM revealed that dialysis adequacy did not affect patient survival. However, diabetes (HR 2.78, p < 0.001), older age (per 1 year: HR 1.06; p < 0.001), serum albumin level (per 1 g/dL: increase, HR 0.52; p < 0.05), and cardiovascular comorbidities (HR 2.32, p < 0.01) were identified as significant risk factors.

Conclusion

Technique survival has improved due partly to a decrease in peritonitis, which was attributed to a decrease in gram-positive peritonitis. Patient survival has also improved considering increases in aged patients and ESRD caused by diabetes. The mortality rate of CAPD is still high in older, diabetic, malnourished, and cardiovascular diseased patients. A more careful management of higher risk groups will be needed to improve the outcome of CAPD patients in the future.

Uremic Toxicity of Advanced Glycation End Products in CKD

Advanced glycation end products (AGEs), a heterogeneous group of compounds formed by nonenzymatic glycation reactions between reducing sugars and amino acids, lipids, or DNA, are formed not only in the presence of hyperglycemia, but also in diseases associated with high levels of oxidative stress, such as CKD. In chronic renal failure, higher circulating AGE levels result from increased formation and decreased renal clearance. Interactions between AGEs and their receptors, including advanced glycation end product-specific receptor (RAGE), trigger various intracellular events, such as oxidative stress and inflammation, leading to cardiovascular complications. Although patients with CKD have a higher burden of cardiovascular disease, the relationship between AGEs and cardiovascular disease in patients with CKD is not fully characterized. In this paper, we review the various deleterious effects of AGEs in CKD that lead to cardiovascular complications and the role of these AGEs in diabetic nephropathy. We also discuss potential pharmacologic approaches to circumvent these deleterious effects by reducing exogenous and endogenous sources of AGEs, increasing the breakdown of existing AGEs, or inhibiting AGE-induced inflammation. Finally, we speculate on preventive and therapeutic strategies that focus on the AGE-RAGE axis to prevent vascular complications in patients with CKD.

Metabolic regulation and function of glutathione peroxidase-1

Glutathione peroxidase-1 (GPX1) represents the first identified mammalian selenoprotein, and our understanding in the metabolic regulation and function of this abundant selenoenzyme has greatly advanced during the past decade. Selenocysteine insertion sequence-associating factors, adenosine, and Abl and Arg tyrosine kinases are potent, Se-independent regulators of GPX1 gene, protein, and activity. Overwhelming evidences have been generated using the GPX1 knockout and transgenic mice for the in vivo protective role of GPX1 in coping with oxidative injury and death mediated by reactive oxygen species. However, GPX1 exerts an intriguing dual role in reactive nitrogen species (RNS)-related oxidative stress. Strikingly, knockout of GPX1 rendered mice resistant to toxicities of drugs including acetaminophen and kainic acid, known as RNS inducers. Intracellular and tissue levels of GPX1 activity affect apoptotic signaling pathway, protein kinase phosphorylation, and oxidant-mediated activation of NFkappaB. Data are accumulating to link alteration or abnormality of GPX1 expression to etiology of cancer, cardiovascular disease, neurodegeneration, autoimmune disease, and diabetes. Future research should focus on the mechanism of GPX1 in the pathogeneses and potential applications of GPX1 manipulation in the treatment of these disorders.

Effects of icodextrin on glycemic and lipid profiles in diabetic patients undergoing peritoneal dialysis

AIM

Icodextrin reduces glucose absorption from the peritoneal dialysate. We conducted this prospective, open-labeled, multicenter study to determine the effects of icodextrin on glycemic and lipid parameters in diabetic patients undergoing continuous ambulatory peritoneal dialysis (PD) or automated PD.

METHODS

Patients were recruited from 15 institutions in Japan, and a total of 51 patients (15 women and 36 men, mean age: 59 +/- 10 years, median duration of PD: 13 months) were enrolled. The patients were administered an overnight or daytime dwell of 1.5 or 2.0 l of 7.5% icodextrin-containing solution. At baseline and 3, 6, 9 and 12 months after the start of icodextrin, nonfasting blood was drawn for measurement of glycated hemoglobin (HbA1C) and serum lipids.

RESULTS

During icodextrin treatment, there was no change in overall HbA1C levels compared to baseline values; however, for those with baseline HbA1C > or =6.5% (n = 22), significant decreases in HbA1C were observed. Mean total/LDL cholesterol and triglycerides were decreased significantly during icodextrin treatment, with greater decreases for patients with baseline total cholesterol > or =220 mg/dl, LDL cholesterol > or =120 mg/dl or triglycerides > or =150 mg/dl. HDL cholesterol did not differ at any time point; however, values for patients with baseline HDL cholesterol <40 mg/dl tended to increase with marginal significance.

CONCLUSIONS

In the current study, switching from glucose-containing dialysis solution to icodextrin resulted in improved lipid profiles and possibly a favorable metabolic profile, particularly in patients with poor glycemic control. These hypotheses remain to be proven in controlled clinical trials.

The pathogenesis of myocardial fibrosis in the setting of diabetic cardiomyopathy

Diabetes has emerged as a major threat to worldwide health. The increasing incidence of diabetes in young individuals is particularly worrisome given that the disease is likely to evolve over a period of years. In 1972, the existence of a diabetic cardiomyopathy was proposed based on the experience with four adult diabetic patients who suffered from congestive heart failure in the absence of discernible coronary artery disease, valvular or congenital heart disease, hypertension, or alcoholism. The exact mechanisms underlying the disease are unknown; however, an important component of the pathological alterations observed in these hearts includes the accumulation of extracellular matrix (ECM) proteins, in particular collagens. The excess deposition of ECM in the heart mirrors what occurs in other organs such as the kidney and peritoneum of diabetics. Mechanisms responsible for these alterations may include the excess production, reduced degradation, and/or chemical modification of ECM proteins. These effects may be the result of direct or indirect actions of high glucose concentrations. This article reviews our state of knowledge on the effects that diabetes-like conditions exert on the cells responsible for ECM production as well as relevant experimental and clinical data.

Vascular Endothelial Growth Factor in Gingival Tissues and Crevicular Fluids of Diabetic and Healthy Periodontal Patients

BACKGROUND

Periodontal disease is one of the major oral problems encountered in patients with diabetes mellitus (DM). Vascular changes, neutrophil dysfunction, altered collagen synthesis, and genetic predisposition observed in DM may contribute to periodontitis; and the vascular alterations observed in such patients may depend on vascular endothelial growth factor (VEGF) actions. Few reports are available about the mechanism of neovascularization and the angiogenic factors that contribute to the periodontal pathology and the role of VEGF in periodontal diseases. The aim of this study is to compare VEGF expression in healthy and periodontally diseased tissues with gingival crevice fluid (GCF) of healthy persons and diabetic patients.

METHODS

Gingival tissue and GCF samples were collected from sites of periodontitis in 10 healthy subjects and in 10 type 2 diabetic patients, and from the sites of healthy gingiva within the same groups. Therefore, each patient became his/her own control. Additionally, 10 people without any systemic or periodontal diseases were enrolled, forming a negative control group. Thus, a total of 50 tissue and 50 GCF samples were provided.

RESULTS

No VEGF staining was observed in the negative control group or in the systemically healthy people's healthy tissue samples, whereas four samples of diabetic patients showed positive staining (P < 0.05). However, VEGF was revealed in two tissue samples of periodontal sites of systemically healthy people and in six samples of the diabetic patients (P > 0.05). In all test groups, GCF VEGF levels were higher in periodontal sites (P < 0.05) than in healthy sites.

CONCLUSION

The results of this study showed that VEGF is increased in all periodontal tissues of both groups and in the healthy sites of diabetic patients. Additionally, GCF VEGF values increased in periodontal sites of all test groups.

Combined ETA/ETB receptor blockade of human peritoneal mesothelial cells inhibits collagen I RNA synthesis

BACKGROUND

Peritoneal fibrosis is a serious complication of peritoneal dialysis; however, the mechanisms are poorly understood. We studied osmolarity and physical stress-induced effects on collagen I RNA synthesis in human peritoneal mesothelial cells (HPMCs) and focused on endothelin as a possible mediator.

METHODS

HPMCs were grown in a medium containing either d-glucose or glycerol to analyze the impact of osmolarity on mesothelial endothelin-1 (ET-1) release and on collagen I RNA synthesis [reverse transcription-polymerase chain reaction (RT-PCR)]. A cellular model of nonlaminar fluid shear stress and cellular stretch was used to analyze the effects of physical forces. To neutralize the endothelin effects, a combined ETA/ETB receptor antagonist (LU 302 872) was chosen.

RESULTS

Glucose, but not glycerol, increased mesothelial ET-1 release in a concentration and time-dependent manner (P < 0.05 vs. controls). Collagen I RNA synthesis was significantly higher in glucose-challenged cell cultures (P < 0.05 vs. controls). The glucose-mediated collagen I RNA synthesis was completely inhibited by adding the combined ETA/ETB receptor antagonist to the medium. Fluid shear stress, but not cellular stretch, led to a significant increase in the mesothelial ET-1 release (P < 0.005 vs. controls) and collagen I RNA synthesis (P < 0.05 vs. controls). LU 302 872 completely inhibited these effects.

CONCLUSION

We found that glucose and fluid shear stress are potent stimuli for ET-1 release and collagen I RNA synthesis in a model cellular system. Although our system is highly artificial, our findings raise the hypothesis that similar effects may occur in the peritoneal membranes of peritoneal dialysis patients and suggest that endothelin might be involved.

Expression of vascular endothelial growth factor in human periodontal tissues: comparison of healthy and diabetic patients

BACKGROUND

Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells, stimulates angiogenesis, and increases vascular permeability, but information about its role in periodontal lesions is limited. The aim of this study is to determine the association between VEGF expression in healthy and periodontally diseased tissues of healthy and diabetic patients.

METHODS

Ten systemically healthy and 10 Type 2 diabetic patients (DM) all diagnosed with periodontitis were enrolled into the study. Gingival samples were collected from both periodontal and healthy sites in all patients. Each patient served as his/her own control. Additionally, 10 people without any systemic or periodontal diseases were enrolled as a negative control group.

RESULTS

In the negative control group tissue samples, no VEGF expression was observed. Among the 10 systemically healthy people, no evidence of VEGF was observed in healthy gingival samples, but was found in diseased tissues in 2 cases. In the diabetic patients, VEGF was observed in 4 healthy gingival tissues and in 6 periodontal sites. VEGF was intensely present in monocytes and macrophages.

CONCLUSION

The results of this study show that VEGF is increased in gingival tissues of diabetic patients, especially those with periodontal disease.