The effect of age, diabetes, and other comorbidity on the survival of patients on dialysis: a systematic quantitative overview of the literature

Long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living, life expectancy, and the risk factors for postoperative mortality

BACKGROUND

Because of the high incidence of major perioperative adverse events, spine surgery in dialysis patients should be recommended carefully after consideration of its risks and benefits. However, the benefits of spine surgery in dialysis patients remain unclear because of the lack of long-term outcomes. The purpose of this study is to elucidate the long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living (ADLs), life expectancy, and risk factors for postoperative mortality.

METHODS

Data for 65 dialysis patients who underwent spine surgery at our institution and were followed up for a mean duration of 6.2 years were retrospectively reviewed. ADLs, number of surgeries, and survival times were recorded. The postoperative survival rate was calculated using the Kaplan-Meier method, and risk factors for postoperative mortality were investigated using a generalized Wilcoxon test and multivariate Cox proportional-hazards model.

RESULTS

Compared with preoperative ADLs, ADLs significantly improved at discharge after surgery and at the final follow-up. However, 16 of the 65 patients (24.6%) underwent multiple surgeries, and 34 (52.3%) died during the follow-up period. Kaplan-Meier analysis revealed that the survival rate after spine surgery was 95.4% at 1 year, 86.2% at 3 years, 69.6% at 5 years, 59.7% at 7 years, and 28.7% at 10 years, and the overall median survival time was 99 months. Multivariate Cox regression analysis showed that a dialysis period of ≥10 years was a significant risk factor.

CONCLUSIONS

Spine surgery in dialysis patients improved and maintained ADLs in the long term and did not shorten life expectancy. However, dialysis patients undergoing spine surgery require multiple surgeries more frequently, and a dialysis period of ≥10 years is a significant risk factor for postoperative mortality.

Inflammation in Peritoneal Dialysis: A Latin-American Perspective

Peritoneal dialysis (PD) patients present an extremely high mortality rate, but the mechanisms mediating the increased risk of mortality observed in this group of patients are still largely unknown, which limits the perspective of effective therapeutic strategies. The leading hypothesis that tries to explain this high mortality risk is that PD patients are exposed to a number of traditional risk factors for cardiovascular disease (CVD) already at the onset of their chronic kidney disease (CKD), since many of these risk factors are common to both CVD and CKD. Of particular importance, chronic inflammation recently emerged as an important novel risk factor related to multiple complications of CKD. There are many stimuli of the inflammatory response in CKD patients, such as fluid overload, decreased cytokine clearance, presence of uremia-modified proteins, presence of chronic infections, metabolic disturbances (including hyperglycemia), obesity. Many of these factors are related to PD. Latin America has made some progress in economic issues; however, a large portion of the population is still living in poverty, in poor sanitary conditions, and with many health-related issues, such as an increasing elderly population, low birth weights, and increasingly high energy intake in the adult population, which, in combination with changes in lifestyle, has provoked an increase in the prevalence of obesity, diabetes, and CVD. Therefore, in Latin America, there seems to be a peculiar situation combining high prevalence of low education level, poor sanitary conditions, and poverty with increases in obesity, diabetes, and sedentary lifestyle. Since inflammation and mortality risk are intimately related to both sides of those health issues, in this review we aim to analyze the peculiarities of inflammation and mortality risk in the Latin-American PD population.

Frailty in hemodialysis and prediction of poor short-term outcome: mortality, hospitalization and visits to hospital emergency services

Background: Frailty is an aging-associated state of increased vulnerability, which raises the risk of adverse outcomes. Chronic kidney disease is associated with higher prevalence of frailty. Our aim was to estimate frailty prevalence in a hemodialysis population and its influence on short-term outcomes.

Design: Observational prospective longitudinal study of 277 prevalent hemodialysis patients. Frailty was estimated through the Edmonton Frail Scale (EFS). Demographic and clinical data, comorbidity index, and laboratory parameters were recorded. A 29-month follow-up was conducted on mortality, including hospitalization, and visits to hospital emergency services in the first 12 months of this period.

Results: According to the EFS, 82 patients (29.6%) were frail, 53 (19.1%) were vulnerable, and 142 (51.3%) were non-frail. During follow-up, 58.5% frail patients, 30.2% vulnerable, and 16.2% non-frail ones died (p < .005). In the analysis of survival using an adjusted Cox model, a higher hazard of mortality was observed in frail than in non-frail patients (HR 2.34; 95% CI 1.39–3.95; p = .001). During follow-up the hospitalization rate was 852 episodes/1000 patient-years for frail patients, 784 episodes/1000 patient-years for vulnerable patients, and 417 episodes/1000 patient-years for non-frail patients (p = .0005). The incidence ratio of visits to emergency services was 3216, 1735, and 1545 visits/1000 patient-years for each group (p < .001).

Conclusions: Hemodialysis patients present high frailty prevalence. Frailty is associated with poor short-term outcomes and higher rates of mortality, visits to hospital emergency services, and hospitalization.

A New Prognostic Index for One-Year Survival in Incident Hemodialysis Patients

Purpose

Although scoring comorbidities for patients beginning chronic hemodialysis has proved significant and has led researchers to develop several indexes, none of them has been extensively accepted. The aim of this study was to: 1) develop a prognostic index for patients entering renal replacement therapy; and 2) identify which one of the available scores better predicts one-year survival.

Methods

Records from 5,360 incident dialysis-requiring ESRD individuals were studied and a novel comorbidity index (NI) was developed. The agreement of this NI with the Charlson age-comorbidity, Kahn-Wright, ACPI, and Hemmelgarn indexes was assessed to identify which one better predicts one-year survival. The Cox proportional hazard regression with time-dependent covariates was used to analyze survival and the area under the receiver operating characteristic (ROC) curve was calculated to assess the ability of this score to discriminate between prognoses and to compare this NI with indexes already in use.

Results

16 of the original 19 predictor variables displayed hazard ratios ≥1.2. Although the area under the ROC curves for all the indexes compared were significantly different from 0.5, the NI showed better performance characteristics (0.74 vs. 0.70 for Charlson's, 0.68 for ACPI, 0.67 for Khan-Wright's and 0.63 for Hemmelgarn's). Compared with the Charlson score, the z statistic was 7.78 (p<0.001). One-year survival estimate for the high-risk group was 43% with the NI and ranged from 66% to 72% when assessed through other indexes.

Conclusions

We recommend the use of this NI because it better predicts the one-year survival probability of incident hemodialysis-requiring ESRD individuals.

Relationship between Hemoglobin Levels Corrected by Interdialytic Weight Gain and Mortality in Japanese Hemodialysis Patients: Miyazaki Dialysis Cohort Study

BACKGROUND

Although hemoglobin (Hb) levels are affected by a change in the body fluid status, the relationship between Hb levels and mortality while taking interdialytic weight gain (IDWG) at blood sampling into account has not yet been examined in hemodialysis patients.

STUDY DESIGN

Cohort study.

SETTING, PARTICIPANTS

Data from the Miyazaki Dialysis cohort study, including 1375 prevalent hemodialysis patients (median age (interquartile range), 69 (60-77) years, 42.3% female).

PREDICTOR

Patients were divided into 5 categories according to baseline Hb levels and two groups based on the median value of IDWG rates at blood sampling at pre-HD on the first dialysis session of the week.

OUTCOMES

All-cause and cardiovascular mortalities during a 3-year follow-up.

MEASUREMENTS

Hazard ratios were estimated using a Cox model for the relationship between Hb categories and mortality, and adjusted for potential confounders such as age, sex, dialysis duration, erythropoiesis-stimulating agent dosage, Kt/V, comorbid conditions, anti-hypertensive drug use, serum albumin, serum C-reactive protein, serum ferritin, and serum intact parathyroid hormone. Patients with Hb levels of 9-9.9 g/dL were set as our reference category.

RESULTS

A total of 246 patients (18%) died of all-cause mortality, including 112 cardiovascular deaths. Lower Hb levels (<9.0g/dL) were associated with all-cause mortality (adjusted HRs 2.043 [95% CI, 1.347-3.009]), while Hb levels were not associated with cardiovascular mortality. When patients were divided into two groups using the median value of IDWG rates (high IDWG, ≥5.4% and low IDWG, <5.4%), the correlation between lower Hb levels and all-cause mortality disappeared in high IDWG patients, but was maintained in low IDWG patients (adjusted HRs 3.058 [95% CI,1.575-5.934]). On the other hand, higher Hb levels (≥12g/dL) were associated with cardiovascular mortality in high IDWG patients (adjusted HRs 2.724 [95% CI, 1.010-7.349]), but not in low IDWG patients.

CONCLUSION

In hemodialysis patients, target Hb levels may need to be selected in consideration of IDWG at blood sampling.

Clinical outcomes and mortality in elderly peritoneal dialysis patients

OBJECTIVES

To evaluate the clinical outcomes and identify the predictors of mortality in elderly patients undergoing peritoneal dialysis.

METHODS

We conducted a retrospective study including all incident peritoneal dialysis cases in patients ≥65 years of age treated from 2001 to 2014. Demographic and clinical data on the initiation of peritoneal dialysis and the clinical events during the study period were collected. Infectious complications were recorded. Overall and technique survival rates were analyzed.

RESULTS

Fifty-eight patients who began peritoneal dialysis during the study period were considered for analysis, and 50 of these patients were included in the final analysis. Peritoneal dialysis exchanges were performed by another person for 65% of the patients, whereas 79.9% of patients preferred to perform the peritoneal dialysis themselves. Peritonitis and catheter exit site/tunnel infection incidences were 20.4±16.3 and 24.6±17.4 patient-months, respectively. During the follow-up period, 40 patients were withdrawn from peritoneal dialysis. Causes of death included peritonitis and/or sepsis (50%) and cardiovascular events (30%). The mean patient survival time was 38.9±4.3 months, and the survival rates were 78.8%, 66.8%, 50.9% and 19.5% at 1, 2, 3 and 4 years after peritoneal dialysis initiation, respectively. Advanced age, the presence of additional diseases, increased episodes of peritonitis, the use of continuous ambulatory peritoneal dialysis, and low albumin levels and daily urine volumes (<100 ml) at the initiation of peritoneal dialysis were predictors of mortality. The mean technique survival duration was 61.7±5.2 months. The technique survival rates were 97.9%, 90.6%, 81.5% and 71% at 1, 2, 3 and 4 years, respectively. None of the factors analyzed were predictors of technique survival.

CONCLUSIONS

Mortality was higher in elderly patients. Factors affecting mortality in elderly patients included advanced age, the presence of comorbid diseases, increased episodes of peritonitis, use of continuous ambulatory peritoneal dialysis, and low albumin levels and daily urine volumes (<100 ml) at the initiation of peritoneal dialysis.

Clinical significance of multi-frequency bioimpedance spectroscopy in peritoneal dialysis patients: independent predictor of patient survival

BACKGROUND

It is becoming increasingly evident that the accurate assessment of hydration status is critical to care of a dialysis patient. Using the Body Composition Monitor, different parameters (overhydration (OH), extra-cellular water/total body water (ECW/TBW) or OH/ECW) have been proposed to indicate hydration status. We wished to determine which parameter (if any) was most predictive of all-cause mortality, and if this was independent of nutritional indices.

METHODS

We performed a single-centre retrospective analysis of prospectively collected data of all peritoneal dialysis (PD) patients between 1 January 2008 and 30 March 2012. Record review was undertaken to establish patient survival, clinical and demographic data. Follow-up was continued even after PD technique failure (transfer to haemodialysis) and transplantation.

RESULTS

The study included 529 patients. OH index (OH and OH/ECW) was the independent predictor of mortality in multi-variate analysis. ECW/TBW as a continuous variable was not associated with increased risk of death. In contrast, patients that were severely overhydrated (highest 33%) had hazard ratios (HRs) that were statistically significant irrespective of the parameter used to define hydration. Using OH, severely overhydrated patients had an HR of 1.83 [95% confidence interval (CI) 1.19-2.82, P < 0.01], OH/ECW: 2.09 (95% CI 1.36-3.20, P < 0.001) and ECW/TBW: 2.05 (95% CI 1.31-3.22, P < 0.005).

CONCLUSIONS

Our results also indicated that there was no influence of body mass index (BMI) on the hydration parameter OH/ECW. OH/ECW remained an independent predictor of mortality when the BMI and lean tissue index were included in multivariate model. However, it remains to be determined if correcting the OH status of a patient will lead to improvement in mortality.

Health-related quality of life and long-term survival and graft failure in kidney transplantation: a 12-year follow-up study

BACKGROUND

Although the prognosis of kidney transplantation is generally good, long-term survival varies substantially between patients. This study examined whether health-related quality of life (HRQOL) predicts long-term mortality in kidney transplantation after adjustment for known risk factors.

METHODS

A cohort of 347 (46.77 ± 13.96 years) kidney transplant recipients was followed up for 12 years after enrolment (1999-2001). Patients completed measures of HRQOL and medical records were reviewed to document clinical and cardiovascular risk factors and comorbidities at study entry (mean [SD], 8.57 [6.55] years after transplantation). The primary outcomes were ensuing all-cause mortality and all-cause graft failure (a composite endpoint consisting of return to dialysis therapy, preemptive retransplantation, or death with function). Cox proportional hazards multivariate models were developed to identify predictors of long-term patient and graft survival.

RESULTS

During the 12-year follow-up, 86 (24.8%) patients died, 64 (18.3%) died with a functioning graft, and 35 (11.1%) were placed back to dialysis. Physical QOL impairment increased the risk of mortality and graft failure during the follow-up period. The risk remained significant after adjusting for sociodemographic and clinical risk factors (adjusted hazard ratio, 1.89; 95% confidence interval, 1.09-2.95; P=0.022 and adjusted hazard ratio, 1.68; 95% confidence interval, 1.12-2.52; P=0.012 for patient and graft survival, respectively). Other significant risk factors were older age, time elapsed since transplantation, and Charlson comorbidity index. Risk of graft failure was also associated with glomerular filtration rate.

CONCLUSIONS

Physical HRQOL predicts long-term mortality and graft failure independently of sociodemographic and clinical risk factors in renal transplant patients. Future research should identify the determinants of HRQOL and refine interventions to improve it.

Communicative and critical health literacy, and self-management behaviors in end-stage renal disease patients with diabetes on hemodialysis

OBJECTIVE

Health literacy (HL) has been linked to disease self-management and various health outcomes, and can be separated into components of functional, communicative and critical skills. The high comorbidity between diabetes and end-stage renal disease (ESRD) poses concerns for compromised disease self-management. This study aimed to identify the relationships between HL and self-management behaviors in end-stage renal disease patients with diabetes.

METHODS

Self-report questionnaires measuring HL and self-management with the functional, communicative and critical HL scale and Summary of Diabetes Self-Care Activities, respectively, were implemented with a sample of 63 patients. Socio-demographic and clinical characteristics were obtained from medical records.

RESULTS

Self-management in diabetes was associated with communicative and critical HL, but not functional HL. Educational attainment was associated only with functional HL. No relationship between HL and glycated hemoglobin (HbA1c) was identified.

CONCLUSION

Communicative and critical HL skills are associated with self-management in ESRD patients with diabetes. Education levels are not related to self-management.

PRACTICE IMPLICATIONS

Healthcare professionals and health information aiming to improve self-management in ESRD patients with diabetes should consider their capacities of communicative and critical HL instead of solely assessing functional HL.

A validation study of the Canadian Organ Replacement Register

BACKGROUND AND OBJECTIVES

Accurate and complete documentation of patient characteristics and comorbidities in renal registers is essential to control bias in the comparison of outcomes across groups of patients or dialysis facilities. The objectives of this study were to assess the quality of data collected in the Canadian Organ Replacement Register (CORR) compared with the patient's medical charts.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This cohort study of a representative sample of adult, incident patients registered in CORR in 2005 to 2006 examined the prevalence, sensitivity, specificity, positive and negative predictive values, and κ of comorbid conditions and agreement in coding of patient demographics and primary renal disease between CORR and the patient's medical record. The effect of coding variation on patient survival was evaluated.

RESULTS

Medical records on 1125 patients were reviewed. Agreement exceeded 97% for health card number, date of birth, and sex and 71% (range 46.6 to 89.1%) for the primary renal disease. Comorbid conditions were under-reported in CORR. Sensitivities ranged from 0.89 (95% confidence interval 0.80, 0.92) for hypertension to 0.47 (0.38, 0.55) for peripheral vascular disease. Specificity was >0.93 for all comorbidities except hypertension. Hazard ratios for death were similar whether calculated using data from CORR or the medical record.

CONCLUSIONS

Comorbid conditions are under-reported in CORR; however, the associated risks of mortality were similar whether using the CORR data or the medical record data, suggesting that CORR data can be used in clinical research with minimal concern for bias.

Impact of chronic kidney disease on survival after amputation in individuals with diabetes

OBJECTIVE

To identify factors that influence survival after diabetes-related amputations.

RESEARCH DESIGN AND METHODS

We abstracted medical records of 1,043 hospitalized subjects with diabetes and a lower-extremity amputation from 1 January to 31 December 1993 in six metropolitan statistical areas in south Texas. We identified mortality in the 10-year period after amputation from death certificate data. Diabetes was verified using World Health Organization criteria. Amputations were identified by ICD-9-CM codes 84.11-84.18 and categorized as foot, below-knee amputation, and above-knee amputation and verified by reviewing medical records. We evaluated three levels of renal function: chronic kidney disease (CKD), hemodialysis, and no renal disease. We defined CKD based on a glomerular filtration rate<60 ml/min and hemodialysis from Current Procedural Terminology (CPT) codes (90921, 90925, 90935, and 90937). We used χ2 for trend and Cox regression analysis to evaluate risk factors for survival after amputation.

RESULTS

Patients with CKD and dialysis had more below-knee amputations and above-knee amputations than patients with no renal disease (P<0.01). Survival was significantly higher in patients with no renal impairment (P<0.01). The Cox regression indicated a 290% increase in hazard for death for dialysis treatment (hazard ratio [HR] 3.9, 95% CI 3.07-5.0) and a 46% increase for CKD (HR 1.46, 95% CI 1.21-1.77). Subjects with an above-knee amputation had a 167% increase in hazard (HR 2.67, 95% CI 2.14-3.34), and below-knee amputation patients had a 67% increase in hazard for death.

CONCLUSIONS

Survival after amputation is lower in diabetic patients with CKD, dialysis, and high-level amputations.

Association between arterial stiffness and peritoneal small solute transport rate

While cardiovascular disease accounts for 40-50% of the mortality in dialysis patients, and while a high peritoneal transport in continuous ambulatory peritoneal dialysis (CAPD) is an independent predictor of outcome, it is unclear if there are any links. Aortic stiffness has become established as a cardiovascular risk factor. We thus studied pulse wave velocity (PWV) in CAPD patients to explore the possible link between peritoneal small solute transport and aortic stiffness. CAPD patients (n = 76, 27 M/49 F) in our center were included in the present study. Aortic stiffness was assessed by brachial pulse pressure (PP) and carotid-femoral PWV. Patients' peritoneal small solute transport rate was assessed by D/P(cr) at 4 h. Extracellular water over total body water (E/T ratio) was assessed by means of bioimpedance analysis. C-reactive protein was also measured. Carotid-femoral PWV was positively associated with patients' age (r = 0.555; P < 0.01), time on peritoneal dialysis (r = 0.332; P < 0.01), diabetic status (r = 0.319; P < 0.01), D/P(cr) (r = 0.241; P < 0.05), PP (r = 0.475; P < 0.01), and E/T (r = 0.606; P < 0.01). In a multivariate regression analysis, carotid-femoral PWV was independently determined by E/T (P < 0.01), PP (P < 0.01), age (P < 0.01), and D/P(cr) (P < 0.05). D/P(cr), in addition to E/T, age, and PP, was an independent predictor of elevated carotid-femoral PWV in CAPD patients, suggesting that there might be a link between high aortic stiffness and increased peritoneal small solute transport rate.

Association between arterial stiffness and peritoneal fluid kinetics

BACKGROUND

A high peritoneal transport status in continuous ambulatory peritoneal dialysis (CAPD) patients is associated with a markedly increased morbidity and mortality. While the causes are as yet unknown, overall the proportion of deaths due to cardiovascular disease is estimated at 40-50% among dialysis patients. Arterial stiffness has been established as a cardiovascular risk factor, while the links between peritoneal transport status and aortic stiffness have not yet been investigated.

METHODS

We included 65 prevalent CAPD patients (24 males/41 females) from our center in a cross-sectional study. Arterial stiffness was assessed by brachial pulse pressure (PP) and carotid-femoral pulse wave velocity (C-F PWV). The patients' peritoneal fluid transport was assessed by kinetic modeling. The patients' peritoneal small solute transport rate was assessed by D/P(cr) at 4 h. Extracellular water to total body water (E/T) ratio was assessed by means of bioimpedance analysis. C-reactive protein was also measured.

RESULTS

C-F PWV was positively correlated with patients' age (r = 0.489, p < 0.01), diabetic status (r = 0.327, p < 0.01), peritoneal fluid absorption rate (Ke; r = 0.251, p < 0.05), PP (r = 0.483, p < 0.01), and E/T (r = 0.517, p < 0.01). Multivariate regression analysis showed that C-F PWV was independently related to E/T (p < 0.01), PP (p < 0.01), age (p < 0.05), and Ke (p < 0.05).

CONCLUSION

Peritoneal fluid transport (Ke), as well as E/T, age and PP were found to be independent predictors of elevated C-F PWV in CAPD patients, suggesting that there might be a link between high aortic stiffness and increased Ke rate, hypothetically through generalized vasculopathy.

Altered proximal aortic stiffness and endothelin plasma levels in diabetic patients with end-stage renal disease

Peripheral artery stiffness is altered in diabetic patients with end-stage renal disease (ESRD), whereas few data exist to confirm this trend for proximal aortic stiffness. The pulse wave velocity of the proximal aorta (PWVr) and of the carotid-to-femoral aortic segment (PWVcf) were determined by ultrasound imaging in 160 patients with ESRD (70 diabetic) and in 160 matched control subjects. Also, plasma levels of endothelin, homocysteine, and high-sensitivity C-reactive protein were determined in both groups. Patients with ESRD had increased pulse pressure, left ventricular (LV) end-diastolic diameter, LV mass index, PWVr, and PWVcf compared with control subjects (p < 0.05). Diabetic patients had increased LV mass index, PWVr, and PWVcf compared with nondiabetic patients with ESRD (p < 0.05). Endothelin levels exhibited a strong relation with PWVr (r = 0.32, p < 0.001) and PWVcf (r = 0.33, p < 0.001) measurements in ESRD patients. Multivariate linear regression analysis revealed that age, diabetes, and plasma levels of endothelin were major determinants of increased PWVr measurements in the total ESRD population. After adjustment for age, body surface area, time on dialysis, systolic blood pressure, history of hypertension, and plasma endothelin levels, diabetes was an independent factor associated with PWVr in ESRD subjects. Diabetic patients with ESRD had significantly increased proximal aortic stiffness and significantly altered plasma levels of endothelin as compared with the nondiabetic.

Diabetes, glycaemic control and mortality risk in patients on haemodialysis: the Japan Dialysis Outcomes and Practice Pattern Study

AIMS/HYPOTHESIS

There are few data on the target level of glycaemic control among patients with diabetes on haemodialysis. We investigated the impact of glycaemic control on mortality risk among diabetic patients on haemodialysis.

SUBJECTS AND METHODS

Data were analysed from the Dialysis Outcomes Practice Pattern Study (DOPPS) for randomly selected patients on haemodialysis in Japan. The diagnosis of diabetes at baseline and information on clinical events during follow-up were abstracted from the medical records. A Cox proportional hazards model was used to evaluate the association between presence or absence of diabetes, glycaemic control (HbA(1c) quintiles) and mortality risk.

RESULTS

Data from 1,569 patients with and 3,342 patients without diabetes on haemodialysis were analysed. Among patients on haemodialysis, those with diabetes had a higher mortality risk than those without (multivariable hazard ratio 1.37, 95% CI 1.08-1.74). Compared with those in the bottom quintile of HbA(1c) level, the multivariable-adjusted hazard ratio for mortality was not increased in the bottom second to fourth quintiles of HbA(1c) (HbA(1c) 5.0-5.5% to 6.2-7.2%), but was significantly increased to 2.36 (95% CI 1.02-5.47) in the fifth quintile (HbA(1c) > or = 7.3%). The effect of poor glycaemic control did not statistically correlate with baseline mortality risk (p = 0.27).

CONCLUSIONS/INTERPRETATION

Among dialysis patients, poorer glycaemic control in those with diabetes was associated with higher mortality risk. This suggests a strong effect of poor glycaemic control above an HbA(1c) level of about 7.3% on mortality risk, and that this effect does not appear to be influenced by baseline comorbidity status.

Determinants of Arterial Wall Stiffness and Peripheral Artery Occlusive Disease in Nondiabetic Hemodialysis Patients

Aortic pulse wave velocity (Ao-PWV) and ankle-brachial blood pressure index (ABPI) are significant prognostic factors in patients with end-stage renal disease (ESRD). Diabetes mellitus (DM) promotes changes in arterial walls, including marked increases in Ao-PWV and decreases in ABPI. To determine the prevalence of peripheral arterial occlusive disease (PAOD) as well as the clinical variables useful in predicting these changes in nondiabetic patients with ESRD undergoing hemodialysis (HD), we performed a cross-sectional study in a cohort of 143 patients. Ao-PWV and ABPI were measured simultaneously and compared with several annual biochemical measurements and other clinical variables. The prevalence of PAOD in our cohort was 30.5%. In univariate regression analysis, Ao-PWV correlated positively with age, heart rate (HR), blood pressure (BP), pulse pressure (PP) and HbA1c, and negatively with serum albumin and ABPI. ABPI correlated negatively with age, HD duration, systolic BP, PP, low-density lipoprotein (LDL) cholesterol and hypersensitive C-reactive protein (hs-CRP), and positively with serum albumin and bone mineral density. In a step-down multiple regression analysis, HbA1c was identified as an independent determinant of Ao-PWV along with age, HD duration, HR and mean BP, while hs-CRP was an independent contributor to ABPI along with age, HD duration, PP and LDL cholesterol. Our results suggest that HD promotes aortic wall stiffness and PAOD progression. We recommend the monitoring of HbA1c to allow the prediction of aortic wall stiffness in nondiabetic ESRD patients. Our results did not confirm the influence of insulin resistance on the development of arterial sclerosis lesions.

International differences in dialysis mortality reflect background general population atherosclerotic cardiovascular mortality

Existing national, racial, and ethnic differences in dialysis patient mortality rates largely are unexplained. This study aimed to test the hypothesis that mortality rates related to atherosclerotic cardiovascular disease (ASCVD) in dialysis populations (DP) and in the background general populations (GP) are correlated. In a cross-sectional, multinational study, all-cause and ASCVD mortality rates were compared between GP and DP using the most recent data from the World Health Organization mortality database (67 countries; 1,571,852,000 population) and from national renal registries (26 countries; 623,900 population). Across GP of 67 countries (14,082,146 deaths), all-cause mortality rates (median 8.88 per 1000 population; range 1.93 to 15.40) were strongly related to ASCVD mortality rates (median 3.21; range 0.53 to 8.69), with Eastern European countries clustering in the upper and Southeast and East Asian countries in the lower rate ranges. Across DP (103,432 deaths), mortality rates from all causes (median 166.20; range 54.47 to 268.80) and from ASCVD (median 63.39 per 1000 population; range 21.52 to 162.40) were higher and strongly correlated. ASCVD mortality rates in DP and in the GP were significantly correlated; the relationship became even stronger after adjustment for age (R(2) = 0.56, P < 0.0001). A substantial portion of the variability in mortality rates that were observed across DP worldwide is attributable to the variability in background ASCVD mortality rates in the respective GP. Genetic and environmental factors may underlie these differences.

The impact of new comorbidities on nutritional status in continuous ambulatory peritoneal dialysis patients

OBJECTIVE

To study the prevalence and risk factors for malnutrition in a peritoneal dialysis (PD) center with an active PD program.

METHODS

We assessed the nutritional status in 205 continuous ambulatory peritoneal dialysis (CAPD) patients, including stable and unstable patients, by subjective global assessment (SGA), dietary diaries and biochemistry index. Serum C-reactive protein (CRP) levels were examined as inflammatory marker. Fluid status including extracellular water (ECW), intracellular water, and total body water (TBW) was evaluated by multiple-frequency bioelectrical impedance analysis and brachial blood pressure was measured. New comorbidities included systemic infection, congestive heart failure and trauma that occurred within 1 month or less. Cardiovascular disease (CVD) was recorded too. Dialysis adequacy and residual renal function were calculated by a standard technique.

RESULTS

Based on SGA, 15.6% of our CAPD patients were malnourished. The malnourished patients had advanced age, higher CRP and ECW/TBW levels than normally nourished patients (age: 68.78 +/- 11.92 vs. 59.26 +/- 13.46 years, p = 0.001; CRP: 11.98 +/- 20.22 vs. 5.56 +/- 8.30 mg/l, p = 0.004; ECW/TBW: 0.55 +/- 0.16 vs. 0.52 +/- 0.04, p = 0.049). Patients with malnutrition were more prone to have CVD (53.13 vs. 31.79%, p = 0.004) and new comorbidities (65.62 vs. 4.62%, p = 0.023). Multivariate analysis showed new comorbidities, mostly systemic infection, which were associated with nutritional status (p < 0.001). Both ECW/TBW and new comorbidities were associated with serum CRP, CVD and malnutrition (p < 0.001-0.05). In contrast, some traditional factors which were recognized as contributing to malnutrition such as residual renal function, dialysis adequacy, metabolic acidosis, total protein loss, diabetes and Charlson indexes were not different between normally nourished and malnourished patients in the present study.

CONCLUSIONS

Our results suggest that only 15.6% of patients were malnourished in our PD program. Old age, inflammation, CVD, fluid overload and new comorbidities were all associated with malnutrition, with new comorbidities, mostly systemic infections, being the most significant risk factor. However, many traditional factors such as residual renal function, dialysis adequacy and diabetes were not.

Meta-Analysis: Peritoneal Membrane Transport, Mortality, and Technique Failure in Peritoneal Dialysis

Peritoneal membrane solute transport in peritoneal dialysis (PD) patients is assessed by the peritoneal equilibration test, which measures the ratio of creatinine in the dialysate to plasma after a standardized 4-h dwell (D/Pc). Patients then are classified as high, high-average, low-average, or low transporters on the basis of this result. A meta-analysis of observational studies was carried out to characterize the relationship between D/Pc and mortality and technique failure in patients who are on PD. Citations were identified in Medline by using a combination of Medical Subject Heading search terms and key words related to PD, peritoneal membrane permeability/transport, and mortality and technique failure. The table of contents of relevant journals and bibliographies of relevant citations were reviewed in duplicate. Twenty studies that met study criteria were identified. Nineteen studies were pooled to generate a summary mortality relative risk of 1.15 for every 0.1 increase in the D/Pc (95% confidence interval 1.07 to 1.23; P < 001). This result equated to an increased mortality risk of 21.9, 45.7, and 77.3% in low-average, high-average, and high transporters, respectively, as compared with patients with low transport status. Meta-regression analysis showed that the proportion of patients who were on continuous cycler PD within a study was inversely proportional to the mortality risk (P = 0.05). The pooled summary relative risk for death-censored technique failure was 1.18 (95% confidence interval 0.96 to 1.46; P = 0.12) for every 0.1 increase in the D/Pc. This meta-analysis demonstrates that a higher peritoneal membrane solute transport rate is associated with a higher mortality risk and a trend to higher technique failure.

The Role of Glycosaminoglycans and Sulodexide in the Treatment of Diabetic Nephropathy

Diabetic nephropathy occurs in 20-40% of diabetic patients, making it one of the most important causes of end-stage renal disease (ESRD). It has a large impact in terms of associated morbidity and mortality for the individual patient and in terms of costs for healthcare. Several studies have demonstrated that micro- and macroalbuminuria predict cardiovascular morbidity and mortality in patients with diabetes mellitus.Current nephroprotective therapies for diabetic nephropathy include the pursuit of normoglycemia and normotension, and a consensus is emerging that there is a necessity to also achieve as low a level of albuminuria as possible. However, the search for innovative and ancillary approaches to the prevention and treatment of this diabetic complication is warranted since strict metabolic control can be difficult, and sometimes dangerous, to achieve and even diabetic patients responding to ACE inhibitors (ACEIs) or angiotensin II receptor antagonists (angiotensin receptor blockers; ARBs) and metabolic control show progressive renal damage and eventually ESRD. A number of drugs are currently being investigated; glycosaminoglycans are particularly interesting since, in theory, they target the generalized endothelial dysfunction and metabolic defect in matrix and basement membrane synthesis which, according to the Steno hypothesis, are responsible for diabetic nephropathy and macroangiopathy.Treatment with glycosaminoglycans, and with sulodexide in particular, significantly improves albuminuria in type 1 and type 2 diabetic patients with micro- or macroalbuminuria. The albuminuria-lowering effect of sulodexide enhances the effect of ACEI/ARB therapy. Most studies have shown that the effect of sulodexide on albuminuria is sustained, strongly suggesting that favorable chemical and anatomic remodeling is induced by exogenous glycosaminoglycans in renal tisues, as observed in the experimental model.

Prevalence of co-morbidity in different European RRT populations and its effect on access to renal transplantation

BACKGROUND

This study compared the prevalence of co-morbidity in patients starting renal replacement therapy (RRT) between European countries and further examined how co-morbidity affects access to transplantation.

METHODS

In this ERA-EDTA registry special study, 17907 patients from Austria, Catalonia (Spain), Lombardy (Italy), Norway, and the UK (England/Wales) were included (1994-2001). Co-morbidity was recorded at the start of RRT.

RESULTS

The prevalence of co-morbidity was: diabetes mellitus (DM) (primary renal disease and co-morbidity) 28%, ischaemic heart disease (IHD) 23%, peripheral vascular disease (PVD) 24%, cerebrovascular disease (CVD) 14% and malignancy 11%. With exception of malignancy, the prevalence of co-morbidity was highest in Austria, but differences were small among other countries. With exception of DM, males suffered more often from co-morbidity than females. In general, the percentage of haemodialysis was higher in patients with co-morbidity, but treatment modality differed substantially between countries. Using a Cox regression with adjustment for demographics, country, year of start and other co-morbidities, the presence of each of the co-morbid conditions made it less likely [RR; 95%CI] to receive a transplant within 4 years: DM [0.79; 0.70-0.88], IHD [0.59; 0.50-0.70], PVD [0.57; 0.49-0.67], CVD [0.49; 0.39-0.61], and malignancy [0.32; 0.24-0.42]. The age, gender and year of start adjusted relative risk [95%CI] to receive a renal transplant within 4 years ranged from 0.23 [0.19-0.27] for Lombardy (Italy) to 3.86 [3.36-4.45] for Norway (Austria = reference). These international differences existed for patients with and without co-morbidity.

CONCLUSIONS

The prevalence of co-morbidity was highest in Austria but differences were small among other countries. The access to a renal graft was most affected by the presence of malignancy and least affected by the presence of DM. International differences in access to transplantation were only partly due to co-morbid variability.

Critical limb ischaemia as a main cause of death in patients with end-stage renal disease: a single-centre study

BACKGROUND

Patients with end-stage renal disease (ESRD) have a high overall mortality rate, particularly due to cardiovascular morbidity. In an era of decline in cardiovascular diseases and early cardiovascular intervention, non-cardiac diseases seem to have a larger impact on overall mortality.

METHODS

From 1997 to 2003, all incident haemodialysis patients in a single centre were enrolled in this prospective study. Those with clinical signs of vascular disease were examined by coronary or peripheral angiographies. Physicians took the patients' medical histories, examined them and followed them up until the end of the study or death. Causes of death were defined by the physicians.

RESULTS

In all, 322 patients were enrolled in the study, 38% of whom were diabetic. At the start of dialysis treatment, 38% had coronary artery disease (CAD), defined as >50% stenosis of at least one coronary artery or as definite myocardial infarction, and 14% had critical ischaemia of at least one limb (CLI). In all patients with foot lesions, CLI was defined angiographically, as evidenced by stenosis or rarefication of distal vessels in the legs. Patients who died (n = 121) [due to cardiac causes (n = 25), complications of CLI (n = 22), stroke (n = 10), cachexia following a long-standing, non-malignant disease (n = 6), malignancy (n = 24), infection not related to CLI (n = 18) and other causes (n = 16)] were older (71+/-10 vs 65+/-13 years), more often male [74/121 (61%)] and often diabetic [56/121 (46%)]. CAD was documented in 82/121 (68%). Five-year survivals in patients with no risk and diabetes without CAD or CLI, CAD and CLI were 74%, 73%, 50% and 10%, respectively. Age, CLI and smoking habits independently increased the risk of death (hazard ratios: 1.052, 4.921 and 2.292, respectively).

CONCLUSIONS

These results indicate that CLI with associated complications is not only an indicator of high mortality in patients with ESRD, but is also one of the main causes of death.

Mortality and hospitalization in haemodialysis patients in five European countries: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Mortality and hospitalization rates are reported for nationally representative random samples of haemodialysis patients treated at randomly selected dialysis facilities in five European countries participating in the Dialysis Outcomes and Practice Pattern Study (DOPPS) (France, Germany, Italy, Spain and the UK).

RESULTS

In the UK, 28.1% of haemodialysis patients received prior peritoneal dialysis treatment compared with 4.2-8.3% in other countries. Kidney transplantation rates ranged from 3.3 (per 100 patient years) in Italy to 11.6 in Spain. The relative risk (RR) of mortality, adjusted for age, sex and diabetes status was significantly higher in the UK (RR = 1.39, P = 0.02) compared with Italy (reference) and increased in association with age (RR = 1.60 for every 10 years older, P <0.001), diabetes as cause of end-stage renal disease (ESRD) (RR = 1.55, P < 0.001), male patients <65 years (RR = 1.29, P = 0.02) and peritoneal dialysis in the 12 months prior to starting haemodialysis (RR = 1.72, P = 0.06). Hospitalization for cardiovascular disease was highest in France and Germany (0.40 and 0.43 hospitalizations per patient year, respectively) and lowest in the UK (0.19), although cardiovascular comorbidity was similar in the UK and France. Hospitalization rates for vascular access-related infection ranged from 0.01 hospitalizations per patient year in Italy to 0.08 in the UK, consistent with the higher dialysis catheter use in the UK (25%) vs Italy (5%). Hospitalization risk was significantly higher in France than in other Euro-DOPPS countries and was significantly (P < 0.05) associated with prior peritoneal dialysis therapy, peripheral vascular disease, gastrointestinal bleeding in the prior 12 months, diabetes, cancer, cardiac disease, psychiatric disease and recent onset of ESRD (within 30 days of study entry).

CONCLUSIONS

The large differences in haemodialysis practice and outcomes in the Euro-DOPPS countries suggest opportunities for improvement in patient care.

Adverse Prognostic Indicators in Continuous Ambulatory Peritoneal Dialysis Patients without Obvious Vascular or Nutritional Comorbidities

Objectives

Factors that predict the occurrence of vascular events and poor patient survival in continuous ambulatory peritoneal dialysis (CAPD) patients have not been clearly defined. Previous studies have focused on nonselective CAPD patients, in whom pre-existing comorbidity or poor health might complicate interpretation of the significance of individual factors. The present study was conducted with CAPD patients without severe vascular and nutritional comorbidity.

Patients and Methods

This single-center, prospective, observational study was conducted with 66 prevalent CAPD patients without co-existing severe vascular or nutritional problems. The patients were enrolled in January 1999. We monitored baseline demographic data and clinical and laboratory characteristics including average clinic blood pressure (BP), hemoglobin (Hb), serum albumin, intact parathyroid hormone (iPTH), serum cholesterol, triglycerides, dialysate-to-plasma (D/P) creatinine, dialysis adequacy [Kt/V and creatinine clearance (CCr)], and protein equivalent of nitrogen appearance. We followed the patients for 3 years. Outcome measures were actuarial patient survival, time to occurrence of cerebrovascular accident (CVA) and acute myocardial infarction (AMI), technique survival, and hospitalization rate.

Results

Mean age of the patients was 56.7 ± 10.3 years. Mean duration on CAPD at the time of enrollment was 36.4 ± 21.7 months. Nineteen of the patients (28.8%) had diabetes. Most of the patients [ n = 55 (83.3%)] were using three 2-L exchanges daily. Mean body weight was 56.3 ± 12.2 kg. Mean total weekly Kt/V was 1.91 ± 0.47, and mean total weekly CCr was 75.3 ± 30.6 L/1.73 m2. Actuarial patient survival was 96.9% at 1 year, 90.5% at 2 years, and 75.3% at 3 years. Overall technique survival was 96.9% at 1 year, 95.1% at 2 years, and 89.1% at 3 years. Multivariate analysis showed that age, diabetes mellitus (DM), and body size (weight or surface area) were independent predictors of patient survival. We estimated that a 1-kg increase in body weight was associated with a 6% increase in the relative risk of death ( p = 0.015; 95% confidence interval: 1.013 to 1.126). Patients with a body weight of 60 kg or less showed a significantly better 3-year survival as compared with patients with body weight greater than 60 kg (88.1% vs 58.3%, p = 0.0042). No significant predictors were identified for technique failure or occurrence of a major vascular event. High BP and DM were independent predictors for hospitalization. Dialysis adequacy indices and serum albumin showed no significant effect on any outcome measure.

Conclusions

Our study showed that, in addition to age and DM, body size could also be a significant factor affecting survival of CAPD patients. However, the underlying causative mechanisms remain unclear and require further study.

Effect of diabetes on uremic dyslipidemia

Elevated intermediate-density lipoprotein (IDL), a remnant lipoprotein, is an independent risk factor for atherosclerosis in patients with end-stage renal disease (ESRD). Since the presence of diabetes mellitus further increases the risk of cardiovascular mortality in ESRD, we examined the effect of diabetes on IDL among ESRD patients. The subjects were 330 healthy control subjects and 287 patients with end-stage renal disease including 80 patients with type 2 diabetes. As compared with the healthy subjects, the nondiabetic ESRD patients had increased plasma triglyceride and IDL cholesterol. Diabetic patients with ESRD showed a further increase in plasma triglyceride and IDL cholesterol compared with the nondiabetic group. However, the difference in IDL levels between the ESRD groups was no longer significant when subjects were stratified by plasma triglyceride. Plasma triglyceride was correlated with IDL cholesterol. Increased hemoglobin A(1c) was significantly associated with IDL cholesterol in a multiple regression model including age, gender, and the presence of ESRD. Such an association was no longer significant in another model including plasma triglyceride as an additional covariate. Further analysis indicated the positive effects of diabetes and hyperglycemia on plasma triglyceride. These results indicate that increased IDL in ESRD is further deteriorated in the presence of diabetes, and that the adverse effect is accounted for at least partly by hypertriglyceridemia associated with chronic hyperglycemia.

Octogenarians reaching end-stage renal disease: cohort study of decision-making and clinical outcomes

The fate of octogenarians reaching end-stage renal disease (ESRD) is poorly defined, and implicit dialysis rationing may be practiced in this age group. The main objectives of this study were to analyze the characteristics of pre-ESRD octogenarians offered dialysis or not and to identify factors influencing mortality while on dialysis, to improve prognosis assessment and decision-making. In this single-center cohort, 146 consecutive pre-ESRD octogenarians were referred to a nephrology unit over a 12-yr period (1989 to 2000). Main outcome measures were baseline characteristics of patients offered dialysis and conservative therapy and overall and 1-yr survival according to effective treatment. A therapeutic decision was made for 144 patients. Octogenarians who were not proposed dialysis (n = 37) differed from those who were proposed dialysis (n = 107) mainly in terms of social isolation (43.3% versus 14.7%; P = 0.03), late nephrologic referral (51.4% versus 28.9%; P = 0.01), Karnofsky score (55 +/- 18 versus 63 +/- 20; P = 0.03), and diabetic status (22.2% versus 6.5%, P = 0.008). Six patients refused the dialysis proposal. During the 12-yr observation period, 99 patients died (68.7%). Median survival was 28.9 mo (95% CI, 24 to 38) in patients undergoing dialysis, compared with 8.9 mo (95% CI, 4 to 10) in patients treated conservatively (P < 0.0001). In multivariable piecewise Cox analysis, independent predictors of death within 1 yr on dialysis were poor nutritional status, late referral, and functional dependence. Included in a survivor function, these covariates predict groups with low and high 1-yr mortality risk. Beyond 1 yr on dialysis, the only independent predictor of death was the presence of peripheral vascular disease. It is concluded that beside a patient's individual refusal, late referral, social isolation, low functional capacity, and diabetes may have oriented medical decision toward withholding dialysis in a significant proportion of pre-ESRD octogenarians. Although most patients on dialysis experienced a substantial prolongation of life, identification of mortality predictors in this age group should improve the process of decision-making regarding the expected benefit of renal replacement therapy.

Renal services for people with diabetes in the UK

Diabetic nephropathy is a serious complication of diabetes that can lead to endstage renal failure (ESRF). It is now the most common cause of ESRF in patients accepted onto renal replacement therapy (RRT) programmes in the UK. Rates of diabetic ESRF are more common in ethnic minority populations. The risk of developing diabetic ESRF is higher in Type 1 diabetes but in absolute terms more patients with Type 2 diabetes develop ESRF and are treated. There is still unmet need for RRT amongst patients with diabetes who develop ESRF. The shortage of organ donors, especially amongst ethnic minorities, means that dialysis is the mainstay of treatment in patients with diabetes and ESRF. This is now largely hospital haemodialysis with an increasing proportion being delivered in satellite units. Demand for RRT from patients with diabetes will increase due to demographic change and the increasing prevalence of diabetes, particularly Type 2, in the population. To meet this challenge closer liaison between those primarily caring for patients with diabetes (primary care physicians and diabetologists) and nephrologists is required to ensure effective surveillance of renal function, to increase early referral and to agree protocols of subsequent care. Continued expansion of high-quality RRT is needed that ensures equity of access with particular targeting in areas with large ethnic minority populations. A national priority must be an increase in the kidney transplant rate.

Oral sulodexide reduces albuminuria in microalbuminuric and macroalbuminuric type 1 and type 2 diabetic patients: the Di.N.A.S. randomized trial

Diabetic nephropathy may be effectively prevented and treated by controlling glycemia and administering angiotensin-converting enzyme (ACE) inhibitors. However, strict metabolic control can be difficult, and ACE inhibitors may be poorly tolerated and only partially effective, particularly in diabetes mellitus type 2 (DM2), warranting the search for ancillary treatment. Sulodexide is a glycosaminoglycan, a new class of drug that has demonstrated nephroprotective activity in experimental investigations. The Di.N.A.S. study was a randomized, double-blind, placebo-controlled, multicenter, dose-range finding trial to evaluate the extent and duration of the hypoalbuminuric effect of oral sulodexide in diabetic patients. A total of 223 microalbuminuric and macroalbuminuric DM1 and DM2 patients with serum creatinine < or =150 micromol/L and stable BP and metabolic control were recruited. They were randomly allocated to one of four groups: 50 mg/d, 100 mg/d, or 200 mg/d sulodexide daily or placebo for 4 mo (T0 to T4), with 4 mo of follow-up after drug suspension (T4 to T8). Treatment with 200 mg/d sulodexide for 4 mo significantly reduced log albumin excretion rate (logAER) from 5.25 +/- 0.18 at T0 to 3.98 +/- 0.11 at T4 (P < 0.05), which was maintained till T8 (4.11 +/- 0.13; P < 0.05 versus T0). Moreover, the sulodexide-induced percent reductions in AER at T4 were significantly different from the placebo value at T4 and approximately linear to dose increments (30% [confidence limits, 4 to 49%], P = 0.03; 49% [30 to 63%], P = 0.0001; and 74% [64 to 81%], P = 0.0001 in the sulodexide 50, 100, and 200 mg/d groups, respectively. At T8, the sulodexide 200 mg/d group maintained a 62% (45 to 73%) AER significant reduction versus placebo (P = 0.0001). Subanalysis by type of diabetes (DM1 versus DM2, microalbuminuric versus macroalbuminuric, or on concomitant ACE inhibitors versus not on ACE inhibitors) demonstrated similar findings. These effects were obtained without any significant variation in metabolic control and BP or serum creatinine. Very few adverse events were reported; none were serious. In conclusion, a 4-mo course of high doses of sulodexide significantly and dose-dependently improves albuminuria in DM1 and DM2 patients and micro- or macroalbuminuric patients with or without concomitant ACE inhibition. The effect on albuminuria is long-lasting and seemingly additive to the ACE inhibitory effect.

Effects of increased peritoneal clearances on mortality rates in peritoneal dialysis: ADEMEX, a prospective, randomized, controlled trial

Small-solute clearance targets for peritoneal dialysis (PD) have been based on the tacit assumption that peritoneal and renal clearances are equivalent and therefore additive. Although several studies have established that patient survival is directly correlated with renal clearances, there have been no randomized, controlled, interventional trials examining the effects of increases in peritoneal small-solute clearances on patient survival. A prospective, randomized, controlled, clinical trial was performed to study the effects of increased peritoneal small-solute clearances on clinical outcomes among patients with end-stage renal disease who were being treated with PD. A total of 965 subjects were randomly assigned to the intervention or control group (in a 1:1 ratio). Subjects in the control group continued to receive their preexisting PD prescriptions, which consisted of four daily exchanges with 2 L of standard PD solution. The subjects in the intervention group were treated with a modified prescription, to achieve a peritoneal creatinine clearance (pCrCl) of 60 L/wk per 1.73 m(2). The primary endpoint was death. The minimal follow-up period was 2 yr. The study groups were similar with respect to demographic characteristics, causes of renal disease, prevalence of coexisting conditions, residual renal function, peritoneal clearances before intervention, hematocrit values, and multiple indicators of nutritional status. In the control group, peritoneal creatinine clearance (pCrCl) and peritoneal urea clearance (Kt/V) values remained constant for the duration of the study. In the intervention group, pCrCl and peritoneal Kt/V values predictably increased and remained separated from the values for the control group for the entire duration of the study (P < 0.01). Patient survival was similar for the control and intervention groups in an intent-to-treat analysis, with a relative risk of death (intervention/control) of 1.00 [95% confidence interval (CI), 0.80 to 1.24]. Overall, the control group exhibited a 1-yr survival of 85.5% (CI, 82.2 to 88.7%) and a 2-yr survival of 68.3% (CI, 64.2 to 72.9%). Similarly, the intervention group exhibited a 1-yr survival of 83.9% (CI, 80.6 to 87.2%) and a 2-yr survival of 69.3% (CI, 65.1 to 73.6%). An as-treated analysis revealed similar results (overall relative risk = 0.93; CI, 0.71 to 1.22; P = 0.6121). Mortality rates for the two groups remained similar even after adjustment for factors known to be associated with survival for patients undergoing PD (e.g., age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria). This study provides evidence that increases in peritoneal small-solute clearances within the range studied have a neutral effect on patient survival, even when the groups are stratified according to a variety of factors (age, diabetes mellitus, serum albumin levels, normalized protein equivalent of total nitrogen appearance, and anuria) known to affect survival. No clear survival advantage was obtained with increases in peritoneal small-solute clearances within the range achieved in this study.

Dementia in patients undergoing long-term dialysis: aetiology, differential diagnoses, epidemiology and management

Dementia in patients undergoing long-term dialysis has not been clearly defined; however, four different entities have been described. Uraemic encephalopathy is a complication of uraemia and responds well to dialysis. Dialysis encephalopathy syndrome, the result of acute intoxication of aluminium caused by the use of an aluminium-containing dialysate, was a common occurrence prior to 1980. However, using modern techniques of water purification, such acute intoxication can now be avoided. Dialysis-associated encephalopathy/dementia (DAE) is always associated with elevated serum aluminium levels. Pathognomonic morphological changes in the brain have been described, but the mechanism for the entry of aluminium into the CNS is incompletely understood. The mechanisms involved in the pathogenesis of the neurotoxicity associated with aluminium are numerous. Although only a very small fraction of ingested aluminium is absorbed, the continuous oral aluminium intake from aluminium-based phosphate binders, and also of dietary or environmental origin, is responsible for aluminium overload in dialysis patients. Age-related dementia, especially vascular dementia, occurs in patients undergoing long-term dialysis as frequently as it does in the general population. The differential diagnoses of dialysis-associated dementias should include investigation for metabolic encephalopathies, heavy metal or trace element intoxications, and distinct structural neurological lesions such as subdural haematoma, normal pressure hydrocephalus, stroke and, particularly, hypertensive encephalopathy and multi-infarct dementia. To prevent DAE, dietary training programmes should aim to achieve the lowest phosphate intake and pharmacological tools should be used to keep serum phosphate levels below 2 mmol/L. To prevent vascular dementia, lifestyle modification should be undertaken, including optimal physical activity and fat intake, nicotine abstinence, and targeting optimal blood glucose, cholesterol and triglyceride levels, and blood pressure, to those outlined in current recommendations.

Diabetes mellitus, aortic stiffness, and cardiovascular mortality in end-stage renal disease

Cardiovascular mortality is elevated in patients with end-stage renal disease (ESRD), especially in those with diabetes mellitus. Although the higher cardiovascular death rate in diabetic ESRD patients may be the result of more advanced atherosclerotic changes of the arterial wall, this has not been documented previously. Aortic stiffness was compared between ESRD patients with and without diabetes, and the impact of aortic stiffness on cardiovascular mortality was examined in a prospective, observational cohort study. The cohort consisted of 265 ESRD patients on hemodialysis, including 50 diabetic patients studied between June 1992 and December 1998. At baseline, the diabetic ESRD patients had significantly higher aortic pulse wave velocity (PWV), a noninvasive measure of aortic stiffness, than the nondiabetic patients. During a mean follow-up period of 63 mo, 81 deaths, including 36 cardiovascular deaths, were recorded. Kaplan-Meier analysis revealed higher all-cause or cardiovascular mortality rates in the diabetic as compared with the nondiabetic patients and also in those with higher aortic PWV than those with lower aortic PWV. The effect of diabetes on cardiovascular death was significant in the Cox model, including age, years on hemodialysis, gender, smoking, C-reactive protein, hematocrit, and body mass index as covariates. However, when aortic PWV was included as a covariate, the impact of diabetes was no longer significant, whereas aortic PWV was a significant predictor. In a model including 13 covariates, aortic PWV remained a significant predictor for cardiovascular and overall mortality but not for non-cardiovascular death. These results demonstrate that the increased aortic stiffness of the ESRD patients with diabetes mellitus contributed to the higher all-cause and cardiovascular mortality rates.

Risk of death and liver cirrhosis in anti-HCV-positive long-term haemodialysis patients

BACKGROUND

Hepatitis C virus (HCV) infection is the most common cause of chronic liver disease in haemodialysis patients. The aim of this study was to assess the impact of HCV infection on patient survival in a cohort of long-term haemodialysis patients and to evaluate the percentage of anti-HCV-positive patients that evolve to liver cirrhosis.

METHODS

In 1992, 175 patients who had been on intermittent haemodialysis therapy for at least 6 months were included in the study (57 anti-HCV-positive and 118 anti-HCV-negative patients). Evaluation of patient outcome included date and cause of death, kidney transplantation, and the diagnosis of liver cirrhosis. Patient survival was estimated by the Kaplan-Meier method and compared by the log-rank test. The Cox proportional hazards model was used to estimate the risk of death among dialysis patients who were anti-HCV positive. Other prognostic variables studied included age, gender, diabetes mellitus as cause of end-stage renal disease (ESRD), history of previous transplant, transplantation during follow-up, and time on haemodialysis treatment. The diagnosis of liver cirrhosis was made based on clinical and/or histological criteria.

RESULTS

Eight-year patient survival in anti-HCV-positive subjects was lower (32%) than in anti-HCV-negative patients (52%) (log-rank, P=0.03). Four variables were found to be independent prognostic factors in patient survival: age (relative risk (RR) 1.04); diabetes as cause of ESRD (RR 3.6); transplantation during follow-up (RR 0.66) and presence of HCV antibodies (RR 1.62). The causes of death did not differ significantly between groups, except that four anti-HCV-positive patients died from liver disease. Ten (17.5%) of the 57 anti-HCV-positive patients were diagnosed to have liver cirrhosis at a median of 10 years after renal replacement therapy initiation and a median of 7 years after the first ALT level increase.

CONCLUSION

In conclusion, our study shows an increased risk of death among long-term haemodialysis patients infected with HCV compared with non-infected patients. This might be partly explained by the high proportion of these patients that evolve to liver cirrhosis.

The effect of altering eligibility criteria for entry onto a kidney transplant waiting list

BACKGROUND

This paper concerns the allocation of kidneys from cadaveric donors to patients with end-stage renal disease (ESRD). Currently, the decision as to whether or not a particular patient should go onto the renal transplant waiting list is left to the discretion of the local dialysis centre, and is usually based almost entirely upon consideration of each case on its individual merits. Would this person like to have a renal transplant, is this possible, and would it seem reasonable to give them a chance? It could be argued that such an approach may not make best use of a scarce national resource. In this study we explore the effects of altering the eligibility criteria for transplantation to take explicit and quantitative account of the fact that some patients are more likely to die than others.

METHODS

We performed a survey of one unit's dialysis patients to ascertain the characteristics used in practice to determine who should go onto the transplant waiting list and who should not. We then created a computer model to simulate a cohort of ESRD patients, initially of the same size and characteristics as that in the unit surveyed, receiving renal replacement therapy over a period of 10 years. Using this model, we compared four strategies for defining eligibility for transplantation: (1) all patients eligible; (2) standard and medium risk patients eligible; (3) only standard risk patients eligible; and (4) no regrafts performed (standard and medium risk according to definitions in the Renal Association Standards Document).

RESULTS

Strategies of allowing only standard or standard and medium risk patients onto the waiting list most closely reflected the current decisions made regarding eligibility. The different strategies considered in the models necessarily gave rise to very considerable variation in the size of the waiting list at the end of the 10 year period (range 98-368), which would have important practical implications. The predicted mean time of kidney function varied from 9.8 years for strategy 4 (no regrafts) to 10.8 years for strategy 3 (only standard risk patients eligible). However, the different strategies had very little effect on other parameters, such as numbers of deaths and the size of the dialysis population.

CONCLUSIONS

Variation in decision making from centre to centre regarding access to renal transplantation could make up to a 10% (1 year) difference in the expected half-life of renal transplants performed. Information about recipient characteristics is therefore required when making comparisons between outcome in one transplant unit with that in another, or when comparing one immunosuppressive regime with another.