Comparison of patient survival in non-diabetic transplant-listed patients initially treated with haemodialysis or peritoneal dialysis.

BACKGROUND: It is still not known whether patients survive longer on one modality of dialysis compared to the other. We have tried to answer this question using data from the Scottish Renal Registry. METHODS: To avoid the confounding effects of co-morbidity, we limited our survival analysis to those patients listed for a renal transplant and excluded patients with a primary renal diagnosis (PRD) of diabetic nephropathy. We studied patients starting dialysis between 01 January 1982 and 31 December 2006. RESULTS: Three thousand one hundred and ninety-seven patients fulfilled our criteria. A Kaplan-Meier plot showed no difference in survival between initial dialysis modality (log-rank P = 0.996). In the Cox regression model, initial dialysis modality was not a significant predictor of survival; hazard ratio = 0.97 (95% CI 0.80 to 1.18) after adjusting for age, sex and PRD. Age at the start of dialysis, hazard ratio = 1.05 (95% CI 1.04 to 1.06) and a PRD group of 'multi-system disease' or 'unknown' were found to significantly influence survival. When survival was also censored for change in modality, there was no difference in survival over the whole study period with the hazard of death for patients on haemodialysis compared to those on peritoneal dialysis being 1.04 (95% CI 0.78 to 1.38; P = 0.803). Age at the start of dialysis remained a significant predictor of death. CONCLUSIONS: This study shows that there was no survival advantage between initial dialysis modalities in non-diabetic patients who are deemed healthy enough for listing for a renal transplant.

Incidence and outcome of encapsulating peritoneal sclerosis.

BACKGROUND: Studies report variation in the incidence and outcomes of encapsulating peritoneal sclerosis (EPS). This study reports the incidence and outcome of EPS cases in a national cohort of peritoneal dialysis (PD) patients. METHODS: The incident cohort of adult patients who started PD between 1 January 2000 and 31 December 2007 in Scotland (n = 1238) was identified from the Scottish Renal Registry. All renal units in Scotland identified potential EPS cases diagnosed from 1 January 2000 to 31 December 2014, by which point all patients had a minimum of 7 years follow-up from start of PD. RESULTS: By 31 December 2014, 35 EPS cases were diagnosed in the 1238 patient cohort: an overall incidence of 2.8%. The incidence for subgroups with longer PD duration rises exponentially: 1.1% by 1 year, 3.4% by 3 years, 8.8% at 4 years, 9.4% at 5 years and 22.2% by 7 years. Outcomes are poor with mortality of 57.1% by 1 year after diagnosis. Survival analysis demonstrates an initial above-average survival in patients who later develop EPS, which plummets to well below average after EPS diagnosis. CONCLUSIONS: The incidence of EPS is reassuringly low provided PD exposure is not prolonged and this supports ongoing use of PD. However, continuing PD beyond 3 years results in an exponential rise in the risk of developing EPS and deciding whether this risk is acceptable should be made on an individual patient basis.

Derived equations are not precise enough to predict the adequacy of creatinine clearance in peritoneal dialysis patients.

BACKGROUND: Most renal units assess dialysis adequacy in peritoneal dialysis (PD) patients by formal 24-hour collections of urine and effluent dialysate. We sought a reliable method of predicting dialysis adequacy that allows a decrease in the frequency of these formal and cumbersome measurements. METHODS: We created a formula for estimating total creatinine clearances, then assessed the clinical utility of this formula and other published formulae in predicting adequate and inadequate dialysis in PD patients. We collected data over a 6-month period in 2001 from 288 PD patients from 9 centers in Scotland. Four out of every 5 patients were selected at random to create a formula for estimating total creatinine clearance per week, and the fifth patient was used to form a validation group. We plotted creatinine excretion against age, and the resultant linear regression equation was transformed to produce a formula for predicting total creatinine clearance per week, based on patient sex, weight, and serum creatinine. We used the data from the validation subgroup to calculate predictive values for our derived formula and data from all of the patients to calculate predictive values for the Cockcroft and Gault, Jones, and Modification of Diet in Renal Disease Study formulae. RESULTS: Neither our derived formula nor the three published formulae were sufficiently powerful to predict accurately either adequate or inadequate PD clearance. Receiver operator characteristic curves showed that no significant improvement in these predictive values could be achieved by altering either the sensitivity or the specificity. CONCLUSION: Prediction formulae are not accurate enough to detect underdialysis in PD patients.

Predicting 30-minute postdialysis blood urea concentrations using the stop dialysate flow method.

The stop dialysate flow (SDF) method has been the recommended method of postdialysis urea sampling by the Scottish Renal Association since November 1998. However, this method does not lend itself to calculation of Kt/V using currently favored formulas, which require either a 30-minute postdialysis sample or a 20-second "slow flow" sample. We, therefore, derived a formula that uses a 5-minute postdialysis urea sample using the SDF method to estimate the urea concentration at 30 minutes. Blood samples were obtained from 70 hemodialysis patients immediately before dialysis and at 0, 5, and 30 minutes postdialysis. Half of the patients from each unit were randomly selected to form the linear regression equation: Estimated 30-minute urea concentration = 1.06 x (5-minute urea concentration) + 0.22. This equation was validated using the data from the remaining 35 patients. This showed a very close correlation between measured and estimated urea concentration at 30 minutes (R2 = 0.97), and a Bland-Altman plot confirmed this close relationship. The sensitivity, specificity, positive, and negative predictive values of this equation were high when used to estimate 30-minute urea reduction ratio (URR) greater than 65% (100%, 85.7%, 97%, and 100%, respectively) and 30-minute Kt/V greater than 1. 2 (96.7%, 100%, 100%, and 80%, respectively). The coupling of the SDF method with the above formula combines the advantages of simple and reproducible postdialysis blood sampling with an accurate estimation of the 30-minute postdialysis blood urea concentration, URR, and Kt/V. This method should be a useful tool for comparative audit of hemodialysis adequacy.

Peritoneal dialysis-associated peritonitis rates and outcomes in a national cohort are not improving in the post-millennium (2000-2007).

BACKGROUND: Peritoneal dialysis (PD)-related peritonitis remains the leading cause of technique failure and a significant cause of morbidity among PD patients. Rates in the literature vary, reflecting differences in study design and in populations. The objective of the present study was to determine peritonitis incidence and outcomes in Scotland and to compare them with national guidelines. METHODS: All 10 adult renal units in Scotland prospectively collect data relating to peritonitis for all PD patients in Scotland. Complete audit data between 1 January 2000 and 31 December 2007 were analyzed for the study. RESULTS: The 1918 peritonitis episodes in 38 106 PD treatment months yielded a national rate of 1 episode every 19.9 months. The UK Renal Association standard was met every year, but is not consistently improving. The median peritonitis-free survival was 526 days (95% confidence interval: 463 to 589 days). The spectrum of causative organisms reflected those in previous reports, with a culture-negative rate of 19.4%. Nationally, the cure rate was 74.6%, the refractory rate was 22.6%, and the death rate was 2.8%. Outcome varied by organism. Recurrences represented 9.3% of episodes, and technique failure occurred in 14.9%. The peritonitis rate was higher for continuous ambulatory PD patients than for automated PD patients (1 episode every 17.6 months vs 1 episode every 22.3 months, p < 0.001, relative risk: 1.27). There were significant differences between renal units. CONCLUSIONS: This large national PD cohort met targets for peritonitis rates every year during the 8 years covered by the present report, but showed no consistent trend for improvement. Peritonitis remains the main cause of technique failure in Scotland. Peritonitis rates varied widely between the units, which suggests that we should look to the units and countries with lower peritonitis rates to see if we can adopt successful elements of their practice before resigning ourselves to our ongoing peritonitis burden.

AA amyloidosis in a patient with Langerhans cell histiocytosis.

We report the case of a 37-year-old woman who presented with progressive renal dysfunction and proteinuria, in whom renal biopsy confirmed a diagnosis of AA amyloidosis. No evidence of chronic suppurative infection, connective tissue disease or malignancy was found. A past history of Langerhans cell histiocytosis (LCH) diagnosed in childhood was noted for which the patient had been successfully treated with surgical excision, corticosteroids, radiotherapy and chemotherapy. Renal disease in LCH is not widely recognized and thus we describe a patient with LCH in whom AA amyloidosis developed in the absence of any other established cause.

Effectiveness and safety of recombinant human erythropoietin beta in maintaining common haemoglobin targets in routine clinical practice in Europe: the GAIN study.

OBJECTIVE: The Gain effectiveness in Anaemia treatment wIth NeoRecormon (epoetin beta) study (GAIN) evaluated the effectiveness and safety of recombinant human erythropoietin beta in correcting and/or maintaining common haemoglobin (Hb) targets in routine clinical practice in Europe. RESEARCH DESIGN AND METHODS: European 18-month observational, prospective clinical practice study across 217 centres from 13 countries. During a 3-month retrospective period, patients received any erythropoiesis stimulating agent (ESA). For the subsequent 18-month study phase, patients receiving intravenous (IV) epoetin beta or any other ESA were recommended to be switched to subcutaneous (SC) epoetin beta. Presence of anti-erythropoietin antibodies (AEAB) and related outcomes was investigated before and during the study. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov number: NCT00551603. MAIN OUTCOME MEASURES: Correction and maintenance of Hb levels within recommended target range and mean dose requirement to correct and maintain target Hb levels. RESULTS: A total of 4264 patients on haemodialysis received an ESA for treatment of renal anaemia. During the study period, the number of patients who maintained Hb levels in the recommended target range of 10-12 g/dL increased from 57% to 62%. Administration of SC epoetin beta resulted in a 24% lower mean dose requirement to maintain target Hb levels compared to IV administration (p < 0.001). Considerable differences were observed between countries in the study. No patients developed pure red cell aplasia associated with AEAB during observation. CONCLUSION: This observational study suggests that haemodialysis patients who are receiving any ESA via SC or IV administration for treatment of their renal anaemia can be safely and effectively switched to SC epoetin beta to achieve or maintain the currently recommended Hb targets. SC required a lower dose than IV administration to maintain similar efficacy, thereby potentially lowering the drug costs.

Encapsulating peritoneal sclerosis in the new millennium: a national cohort study.

BACKGROUND AND OBJECTIVES: The study aim was to establish the incidence and characterize all encapsulating peritoneal sclerosis (EPS) cases in patients treated by peritoneal dialysis (PD). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The patient cohort, which started PD from January 1, 2000, to December 31, 2007, was identified from the Scottish Renal Registry (n = 1238). Possible EPS cases were identified by the ten adult Scottish renal units. Patient records were examined to ensure cases met diagnostic criteria. RESULTS: Forty-six cases were identified; 19 had their first PD exposure after January 1, 2000. The rate was 1.5%, an incidence of 4.9 per 1000 person-years. The incidence increased with PD duration, with rates of 0, 0.6, 2.0, 3.5, 8.1, 8.8 and 5% at <1, 1 to 2, >2 to 3, >3 to 4, >4 to 5, >5 to 6 and >6 yr PD exposure, respectively. The median PD duration of EPS cases was 5.1 yr (interquartile range [IQR] 3.4 to 6.1 yr). At diagnosis, 12 (26%) were on PD and 33 (72%) were diagnosed <2 yr after PD stopped. The cases had a median of 3.3 episodes of peritonitis (range 0 to 20, IQR 1 to 4.5). Thirty (65%) had used 3.86% dextrose dialysate and 45 (98%) had used Extraneal. The mortality was 42% at 1 yr postdiagnosis with a median survival of 149 d (IQR 61 to 408 d). CONCLUSIONS: The incidence reported in this study may be used to inform patients of the minimum risk of developing EPS on PD.

Peritoneal dialysis-associated peritonitis in Scotland (1999-2002).

BACKGROUND: Peritonitis is a major complication of peritoneal dialysis (PD). We have performed a national study of all patients on PD in Scotland over a 3.5 year period examining the causes of technique failure, rates of peritonitis, causative organisms, clinical outcomes and differences between automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD). METHODS: All 10 adult renal units in Scotland participated in the study and the data include all 1205 patients who were on PD in Scotland from January 1999 to June 2002. The data were collected prospectively by the PD nurses and reported to the Scottish Renal Registry every 6 months. RESULTS: Refractory or recurrent peritonitis was the cause of technique failure in 167 patients (42.6% of all cases of technique failure). There were 928 cases of peritonitis in 1487 patient-years, which equates to an overall peritonitis rate of one episode every 19.2 months. The peritonitis rates for APD and CAPD were similar at one episode every 20.3 months and one episode every 18.6 months, respectively. These results include 88 cases of peritonitis due to relapse or re-infection. There was a statistically significant difference (P = 0.012) in peritonitis rates between units using nasal mupiricin (one episode every 21.9 months) and those that did not (one episode every 18.3 months). Coagulase-negative Staphylococcus was the most common cause of peritonitis (29%), although this rate is lower than in historic studies. The overall initial cure rate was 75%. The initial cure rate for APD was 77.2% and for CAPD was 73.7%. No causative organism was isolated in 17% of cases. CONCLUSION: PD-associated peritonitis is the leading cause of technique failure in Scotland. We validate previous studies showing a decrease in the proportion of peritonitis episodes that are caused by coagulase-negative staphylococci. APD peritonitis rates are not significantly better than CAPD peritonitis rates in Scotland, and the initial cure rates for APD and CAPD are similar.