Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis

We investigated patient and technique survival and factors affecting mortality in Turkish peritoneal dialysis (PD) patients.

This was a retrospective study. 423 PD patients were included. The demographic, clinical, and biochemical data were collected from the medical records. Clinical outcomes were mortality and technique failure.

Mean age at the start of PD was 46.0 ± 14.3 years and mean PD duration was 37.1 ± 28.3 (median: 30, range: 4 – 137) months. Diabetes mellitus was the most common cause of end-stage renal disease (35.2%), followed by hypertension (14.7%). There were 89 (21.0%) deaths. 25 (5.9%) patients received a kidney transplant, 74 (17.4%) patients were transferred to hemodialysis. Estimation of technique survival by Kaplan–Meier was 96.1%, 83.2%, 67.6%, 45.8%, and 33.6% at 1, 3, 5, 8, and 10 years. Technique failure was associated with peritonitis rate [relative risk (RR): 3.22, p < 0.001] and peritoneal Kt/V urea (RR: 0.38, p = 0.001) in the Cox proportional hazards model analysis. Estimation of patient survival by Kaplan–Meier was 96.9%, 83.8%, 68.8%, 50.2%, and 40.7% at 1, 3, 5, 8, and 10 years, respectively. In the Cox proportional hazards model analysis, age (RR: 1.01, p = 0.05), transfer to PD from hemodialysis (RR: 1.84, p = 0.03), comorbid cardiovascular disease (RR: 1.90, p = 0.004), serum creatinine level (RR: 0.75, p < 0.001), total Kt/V urea (RR: 0.34, p < 0.001), peritonitis rate (RR: 1.87, p < 0.001), and dialysate-to-plasma creatinine ratio (RR: 6.49, p = 0.04) predicted mortality.

Even though we cannot conclude with certainty that survival rates in Turkish patients are better than those in the United States and Europe, our results seem to suggest this and warrant further studies adjusted for more extensive demographic features and comorbidities. The factors affecting mortality in Turkish PD patients are similar to other populations.

Peritonitis caused by enteric organisms in peritoneal dialysis (PD) patients is associated with greater morbidity and mortality than peritonitis with non-enteric organisms. One reported risk factor for enteric peritonitis (EP) is gastric acid suppression, with two small studies providing conflicting results. The objective of this study was to determine, using a larger patient population, whether gastric acid suppressants are associated with an increased risk of EP.

Using a single-center case-control design, information on episodes of EP occurring between 2003 and 2006 was collected. Control episodes were all non-enteric episodes of peritonitis that occurred during the same time interval. Proton pump inhibitor (PPI) or H₂-blocker (H₂B) use prior to development of peritonitis was documented.

A total of 228 peritonitis episodes among 137 patients met inclusion criteria. In 32% of episodes, the causative organism was enteric. Gastric acid suppressant use was documented in 46% of episodes, with the majority on PPIs. Overall, gastric acid suppression was not associated with a higher EP risk (p = 0.17). In a post hoc analysis, PPIs were not associated with EP [odds ratio (OR) 1.3, 95% confidence interval (CI) 0.7 – 2.4; p = 0.42], whereas H₂Bs were associated with a higher risk of EP (OR 2.9, 95% CI 1.1 – 7.7; p = 0.04), although the number of patients on H₂Bs was small.

Overall, gastric acid suppression was not associated with an increased risk of peritonitis with enteric organisms. While PPI use appears to be safe for PD patients with appropriate indications, the potential risk of EP with H₂Bs requires further investigation.

Social support is an independent risk factor for mortality among new hemodialysis patients. We evaluated the effect of social support on the outcome of Chinese peritoneal dialysis (PD) patients.

We studied 167 prevalent PD patients. They completed the Medical Outcomes Study Social Support Survey, Chinese Version (MOS-SSS-C) questionnaire. Patients were followed for 1 year. Outcome measures included change in nutritional status, hospitalization, and technique and actuarial patient survival.

Actuarial survival was 57.1%, 72.7%, 85.3%, and 88.6% for MOS-SSS-C total score quartiles I, II, III, and IV, respectively (log rank test, p = 0.037). Technique survival was 57.1%, 81.9%, 91.9%, and 91.4% (log rank test, p = 0.0044). By multivariate analysis with the Cox proportional hazard model to adjust for confounders, every 1 point increase in MOS-SSS-C total score was associated with a 0.6% [95% confidence interval (CI) 0.2% – 0.9%, p = 0.003] reduction in the risk of death and a 0.5% (95%CI 0.1% – 1.0%, p = 0.037) reduction in the risk of technique failure. The MOS-SSS-C score had no significant effect on change in nutritional or dialysis adequacy indices, hospitalization, or number of peritonitis episodes in 1 year.

The degree of social support is an important predictor of actuarial and technique survival in Chinese PD patients. Measures to enhance social support may represent an easily achievable means of improving the clinical outcome of PD patients.

The technique failure rate on peritoneal dialysis (PD) remains high despite technical progress. There are no data concerning the contribution of early failure to outcome on PD.

To analyze the importance of early treatment failure in PD and to compare early with late failures with respect to reasons and predictors of risk for failure.

We performed a retrospective study of all patients admitted for PD from October 1983 to June 2005. The end point was PD failure-free survival. Differences between reasons for failure with respect to early (within 6 months) and late failure were analyzed. Multivariate associations of baseline covariates with early and late failure were investigated.

We included 279 patients. 153 (55%) patients experienced PD failure: 97 (63%) of them had technique failure; 56 (37%) patients died due to non-PD-related causes. 29% (n = 44) of all PD failures and 40% (n = 39) of all technique failures occurred within 6 months. Catheter and psychosocial problems contributed more often to early than to late failure, whereas infections, leakages, and hernias contributed equally to early and late failure. Death was the predominant reason for late failure. Female sex was a risk factor for early failure and older age a risk factor for late failure. Higher cholesterol levels were associated with a decreased risk for both early and late failure.

The contribution of early failure to outcome on PD is important, as one third of all PD failures and 40% of all technique failures may occur within the first 6 months, as shown in our study. Due to the retrospective nature and the single-center character, the results cannot be generalized. However, it is important to enhance recognition of patients at high risk for early PD failure prior to initiation of PD, in order to avoid unnecessary surgical interventions and medical complications, and for rational resource allocation.

We previously reported a very high incidence of calciphylaxis, mainly in peritoneal dialysis (PD) patients. Although we identified several risk factors for the condition, including PD, we were unable to identify why our particular unit had such a high frequency of the condition and a reliable treatment.

To assess the apparent changing frequency of the condition and the response to therapy, and to attempt to determine putative factors that might explain our uniquely high incidence of calciphylaxis.

A prospective clinical record was kept on all patients that developed calciphylaxis in our center [both PD and hemodialysis (HD) units] between 1998 and 2006.

Of the 59 patients that developed calciphylaxis, 54 were on PD, 4 were on HD, and 1 was in predialysis. In the PD population, the mean yearly incidence from 1998 to 2003 was 4.5/100 patient-years, falling to 1.3/100 patient-years in 2004 – 2006. The percent of patients not taking calcium salts fell during this time period. Conversion to HD led to marked early improvement. A marked discrepancy between the levels of ionized calcium (routinely used in our center) and corrected serum calcium was found, with most cases of hypercalcemia (corrected) being missed by using ionized values.

The incidence of calciphylaxis is falling dramatically. This may be related partially to reduction in usage of calcium salts. Conversion to HD is beneficial. Our uniquely high incidence of calciphylaxis may be related to our use of ionized calcium levels to monitor these patients.

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis (PD). Gastrointestinal (GI) symptoms affect appetite and dietary intake. Adequate nutrition is especially important if surgical interventions are required.

To investigate the nutritional management of 23 EPS patients that underwent surgical intervention between 1999 and 2005 at Manchester Royal Infirmary, United Kingdom.

EPS was recognized by GI symptoms and diagnostically confirmed by laparotomy, computed tomographic scanning, or biopsy.

Mean time on PD was 74 months (interquartile range 42 – 89 months). During the 12 months pre-diagnosis, 65% of the group showed significant weight loss (p = 0.0001), with 8 patients losing >10% of body weight; 74% of patients experienced significant albumin decrease (p = 0.001); and 56% of patients experienced GI symptoms during the 6 months pre-diagnosis. Nasogastric (NG) feeding was recommended for 8 patients but continued in only 1. 15 patients (mean albumin 27 g/L) commenced parenteral nutrition (PN); 9 patients recovered, with albumin increasing over the 6-month follow-up. Mean hospital time was 62 days for the group receiving neither NG nor PN, compared with 124.3 for the PN/NG group (p = 0.04). In patients that died of EPS, albumin continued to fall at 3 months post-diagnosis.

There is currently little guidance for nutritional management of EPS. From this study we recommend (1) a high level of clinical suspicion for EPS, especially if PD patients have weight loss; (2) PN may be better than NG feeding but further studies into dual enteral nutrition and PN are needed; (3) aggressive nutritional supplementation pre- and postoperatively; and (4) dietitians need to recognize the high risk of refeeding syndrome.

Glucose degradation products (GDPs) are important in the outcome of peritoneal dialysis (PD) treatment. 3,4-dideoxyglucosone-3-ene (3,4-DGE) is the most cytotoxic GDP found in conventionally manufactured fluids and may, in addition, be recruited from 3-deoxyglucosone (3-DG). It is not known what happens with those GDPs in patients during PD. The aim of this study was to investigate if the 3,4-DGE and 3-DG in PD fluids can be found in plasma during treatment.

PD patients were dialyzed with a conventional PD fluid containing 43 μmol/L 3,4-DGE and 281 μmol/L 3-DG. Parallel experiments were performed in rats as well as in vitro with human plasma. The rats were dialyzed with a PD fluid containing 100 μmol/L 3,4-DGE and 200 μmol/L 3-DG.

The concentration of 3,4-DGE in the peritoneum decreased at a much higher rate than 3-DG during the dwell. 3,4-DGE was not, however, detected in the plasma of patients or rats during dialysis. The concentration of 3-DG in plasma peaked shortly after infusion of the fluid to the peritoneal cavity. The concentration of 3,4-DGE during experimental incubation in plasma decreased rapidly, while the concentration of 3-DG decreased only 10% as rapidly or less.

3,4-DGE could not be detected in plasma from either PD patients or rats during dialysis. This is presumably due to its high reactivity. 3-DG may, on the other hand, pass through the membrane and be detected in the blood.

Conventional peritoneal dialysis (PD) solutions elicit vasodilation, which is implicated in the variable rate of solute transport during the dwell. The components causing such vasoactivity are still controversial. This study was conducted to define the vasoactive components of conventional and new PD solutions.

Three visceral peritoneal microvascular levels were visualized by intravital video microscopy of the terminal ileum of anesthetized rats. Anesthesia-free decerebrate conscious rats served as control. Microvascular diameter and blood flow by Doppler measurements were conducted after topical peritoneal exposure to 4 clinical PD solutions and 6 prepared solutions designed to isolate potential vasoactive components of the PD solution.

All clinically available PD solutions produced a rapid and generalized vasodilation at all intestinal microvascular levels, regardless of the osmotic solute. The pattern and magnitude of this dilation was not affected by anesthesia but was determined by arteriolar size, the osmotic solute, and the solution's buffer anion system. The greatest dilation occurred in the small precapillary arterioles and was elicited by conventional PD solution and heat re-sterilized solution containing low glucose degradation products (GDPs). Hypertonic mannitol solutions produced a dilation that was approximately 50% less than the dilation obtained with glucose solutions with identical osmolarity and buffer. Increasing a solution's osmolarity did not produce a parallel increase in the magnitude of dilation, suggesting a nonlinear relationship between the two variables. Lactate dissolved in an isotonic solution was completely non-vasoactive unless the solution's H⁺ concentration was increased. At low pH, isotonic lactate produced a rapid but transient vasodilation. This vascular reactivity was similar in magnitude and pattern to that obtained with the isotonic 7.5% icodextrin solution (Extraneal; Baxter Healthcare, Deerfield, Illinois, USA).

(1) Hyperosmolarity is the major vasoactive component of PD solution. (2) Hyperosmolarity and active intracellular glucose uptake account together for approximately 75% of PD solution-induced dilation, whereas GDPs contribute to approximately 25%. (3) Lactate is vasoactive only at low pH (high [H⁺]). (4) The magnitude of PD solution-mediated vasodilation is partially dependent on the nature of the osmotic solute, the GDP contents, and the [H⁺], which determine the vasoactivity of the lactate-buffer anion system. Studies are required to define the molecular mechanisms of PD-induced vasodilation and to determine the vasoactive properties of these solutions after chronic infusion.

Plasma α–amylase activity is elevated in uremic patients but lower in peritoneal dialysis (PD) patients using icodextrin in comparison to healthy controls. We studied the rate by which an exogenous oligosaccharide (maltoheptaose; G7) is degraded ex vivo by amylase in plasma from PD patients treated with glucose or icodextrin PD solutions.

Plasma amylase (pancreatic and total) activity and concentration were measured in 11 controls and in PD patients treated with glucose (n = 11) and icodextrin (n = 19). The plasma was spiked with G7 and/or synthetic amylase and the metabolites formed were measured by HPLC following incubation at 37°C for 4 hours.

The relationship between amylase activity and amylase concentration was similar in all patients and controls. The G7 degradation rate was slower in plasma from icodextrin patients but it was also reduced in patients using glucose compared with the controls, in spite of the higher amylase activity in the glucose group. Normalization (by spiking) of patient plasma with porcine amylase increased but did not normalize the speed of G7 degradation. At a given endogenous amylase activity level, the efficiency of G7 degradation was similar for both patient groups.

An ex vivo model to study the relationship between amylase activity and the actual rate of carbohydrate (represented by G7) breakdown was developed and showed that PD patients using glucose and icodextrin degrade G7 at a slower speed than controls. This suggests that amylase-mediated carbohydrate metabolism is reduced in PD patients. Further clinical studies are needed to confirm if these findings hold true also in other groups of uremic patients with varying degrees of kidney failure, as well as in patients undergoing hemodialysis.