Confounding effect of comorbidity in survival studies in patients on renal replacement therapy

A Longitudinal Dose-Response Curve Between Leisure-Time Physical Activity and the Prevalence of Diabetes Based on the Different Levels of Cognitive Function Among Older Adults

This study investigated a dose-response relationship between Leisure-Time Physical Activity participation (LTPA) and the risk of diabetes and a comparison of the risk across different cognitive function groups among older adults. The Health and Retirement Study data were used from 2012 to 2020 (n = 18 746). This study conducted a Cox Proportional Hazard Regression to investigate the Dose-Response Curve between the prevalence of diabetes and the covariates following a level of LTPA participation. The result presented that the Odds Ratio continuously decreased as the level of LTPA participation increased. Among the three cognitive function groups, the high group (OR = .43, P < .05) and the mid group (OR = .71, P < .05) had a larger negative slope coefficient than the low group. This study found that LTPA participation reduces the risk of diabetes and gives evidence for the importance of cognitive function in reducing the prevalence of diabetes.

Increasing numbers and improved overall survival of patients on kidney replacement therapy over the last decade in Europe: an ERA Registry study

INTRODUCTION

The aim of this study was to describe the trends in the incidence, prevalence and survival of patients on kidney replacement therapy (KRT) for end-stage kidney disease (ESKD) across Europe from 2008 to 2017.

METHODS

Data from renal registries in 9 countries and 16 regions that provided individual patient data to the ERA Registry from 2008 to 2017 were included. These registries cover 34% of the general population in Europe. Crude and standardized incidence and prevalence per million population (pmp) were determined. Trends over time were studied using Joinpoint regression. Survival probabilities were estimated using Kaplan-Meier analysis and hazard ratios (HRs) using Cox regression analysis.

RESULTS

The standardized incidence of KRT was stable (annual percentage change [APC]: -1.48 [-3.15; 0.21]) from 2008 (146.0 pmp) to 2011 (141.6 pmp), followed by a slight increase (APC: 1.01 [0.43; 1.60]) to 148.0 pmp in 2017, although trends in incidence varied across countries. This increase was primarily due to a rise in the incidence of KRT in men older than 65 years. Moreover, as a cause of kidney failure, diabetes mellitus is increasing. The standardized prevalence increased from 2008 (990.0 pmp) to 2017 (1166.8 pmp) (APC: 1.82 [1.75; 1.89]). Patient survival on KRT improved in the time period 2011-2013 compared with 2008-2010 (adjusted HR: 0.94 [0.93; 0.95).

CONCLUSION

This study showed an overall increase in the incidence and prevalence of KRT for ESKD as well as an increase in the KRT patient survival over the last decade in Europe.

Survival and predictors of mortality among chronic kidney disease patients on hemodialysis in Amhara region, Ethiopia, 2021

BACKGROUND

Despite the high economic and mortality burden of chronic kidney disease, studies on survival and predictors of mortality among patients on hemodialysis in Ethiopia especially in the Amhara region are scarce considering their importance to identify some modifiable risk factors for early mortality to improve the patient's prognosis. So, this study was done to fill the identified gaps. The study aimed to assess survival and predictors of mortality among end-stage renal disease patients on hemodialysis in Amhara regional state, Ethiopia, 2020/2021.

METHOD

Institution-based retrospective record review was conducted in Felege Hiwot, Gonder, and Gambi hospitals from March 5 to April 5, 2021. A total of 436 medical records were selected using a simple random sampling technique. A life table was used to estimate probabilities of survival at different time intervals. Multivariable cox regression was used to identify risk factors for mortality.

RESULT

Out of the 436 patients 153 (35.1%) had died. The median survival time was 345 days with a mortality rate of 1.89 per 1000 person-days (95%CI (1.62, 2.22)). Patients live in rural residences (AHR = 1.48, 95%CI (1.04, 2.12)), patients whose cause of CKD was hypertension (AHR = 1.49, 95%CI (1.01, 2.23)) and human immune virus (AHR = 2.22, 95%CI (1.41, 3.51)), and patients who use a central venous catheter (AHR = 3.15, 95%CI (2.08, 4.77)) had increased risk of death while staying 4 h on hemodialysis (AHR = 0.43, 95%CI (0.23, 0.80)) decreases the risk of death among chronic kidney disease patients on hemodialysis.

CONCLUSIONS

The overall survival rate and median survival time of chronic kidney disease patients on hemodialysis were low in the Amhara region as compared with other developing Sub-Saharan African counties.

Primary kidney disease modifies the effect of comorbidities on kidney replacement therapy patients' survival

BACKGROUND

Comorbidities are associated with increased mortality among patients receiving long-term kidney replacement therapy (KRT). However, it is not known whether primary kidney disease modifies the effect of comorbidities on KRT patients' survival.

METHODS

An incident cohort of all patients (n = 8696) entering chronic KRT in Finland in 2000-2017 was followed until death or end of 2017. All data were obtained from the Finnish Registry for Kidney Diseases. Information on comorbidities (coronary artery disease, peripheral vascular disease, left ventricular hypertrophy, heart failure, cerebrovascular disease, malignancy, obesity, underweight, and hypertension) was collected at the start of KRT. The main outcome measure was relative risk of death according to comorbidities analyzed in six groups of primary kidney disease: type 2 diabetes, type 1 diabetes, glomerulonephritis (GN), polycystic kidney disease (PKD), nephrosclerosis, and other or unknown diagnoses. Kaplan-Meier estimates and Cox regression were used for survival analyses.

RESULTS

In the multivariable model, heart failure increased the risk of death threefold among PKD and GN patients, whereas in patients with other kidney diagnoses the increased risk was less than twofold. Obesity was associated with worse survival only among GN patients. Presence of three or more comorbidities increased the age- and sex-adjusted relative risk of death 4.5-fold in GN and PKD patients, but the increase was only 2.5-fold in patients in other diagnosis groups.

CONCLUSIONS

Primary kidney disease should be considered when assessing the effect of comorbidities on survival of KRT patients as it varies significantly according to type of primary kidney disease.

One- and 2-Year Mortality Prediction for Patients Starting Chronic Dialysis

Introduction

Mortality risk of patients with end-stage renal disease (ESRD) is highly elevated. Methods to estimate individual mortality risk are needed to provide individualized care and manage expanding ESRD populations. Many mortality prediction models exist but have shown deficiencies in model development (data comprehensiveness, validation) and in practicality. Therefore, our aim was to design 2 easy-to-apply prediction models for 1- and 2-year all-cause mortality in patients starting long-term renal replacement therapy (RRT).

Methods

We used data from the Finnish Registry for Kidney Diseases with complete national coverage of RRT patients. Model training group included all incident adult patients who started long-term dialysis in Finland in 2000 to 2008 (n = 4335). The external validation cohort consisted of those who entered dialysis in 2009 to 2012 (n = 1768). Logistic regression with stepwise variable selection was used for model building.

Results

We developed 2 prognostic models, both of which only included 6 to 7 variables (age at RRT start, ESRD diagnosis, albumin, phosphorus, C-reactive protein, heart failure, and peripheral vascular disease) and showed sufficient discrimination (c-statistic 0.77 and 0.74 for 1- and 2-year mortality, respectively). Due to a significantly lower mortality in the newer cohort, the models, to a degree, overestimated mortality risk.

Discussion

Mortality prediction algorithms could be more widely implemented into management of ESRD patients. The presented models are practical with only a limited number of variables and fairly good performance.

Factors affecting outcomes in patients reaching end-stage kidney disease worldwide: differences in access to renal replacement therapy, modality use, and haemodialysis practices

More than 2 million people worldwide are being treated for end-stage kidney disease (ESKD). This Series paper provides an overview of incidence, modality use (in-centre haemodialysis, home dialysis, or transplantation), and mortality for patients with ESKD based on national registry data. We also present data from an international cohort study to highlight differences in haemodialysis practices that affect survival and the experience of patients who rely on this therapy, which is both life-sustaining and profoundly disruptive to their quality of life. Data illustrate disparities in access to renal replacement therapy of any kind and in the use of transplantation or home dialysis, both of which are widely considered preferable to in-centre haemodialysis for many patients with ESKD in settings where infrastructure permits. For most patients with ESKD worldwide who are treated with in-centre haemodialysis, overall survival is poor, but longer in some Asian countries than elsewhere in the world, and longer in Europe than in the USA, although this gap has reduced. Commendable haemodialysis practice includes exceptionally high use of surgical vascular access in Japan and in some European countries, and the use of longer or more frequent dialysis sessions in some countries, allowing for more effective volume management. Mortality is especially high soon after ESKD onset, and improved preparation for ESKD is needed including alignment of decision making with the wishes of patients and families.

Prediction of Mortality in Incident Hemodialysis Patients: A Validation and Comparison of CHADS2, CHA2DS2, and CCI Scores

Background

The CHADS2 and CHA2DS2 scores are usually applied for stroke prediction in atrial fibrillation patients, and the Charlson comorbidity index (CCI) is a commonly used scale for assessing morbidity. The role in assessing mortality with score system in hemodialysis is not clear and comparisons are lacking. We aimed at evaluating CHADS2, CHA2DS2, and CCI scores to predict mortality in incident hemodialysis patients.

Methods

Using data from the Nation Health Insurance system of Taiwan (NHIRD) from 1 January 2005 to 31 December 2009, individuals ≧20 y/o who began hemodialysis identified by procedure code and receiving dialysis for > 3 months were included for our study. Renal transplantation patients after dialysis or PD patients were excluded. We calculated the CHADS2, CHA2DS2, and CCI score according to the ICD-9 code and categorized the patients into three groups in each system: 0–1, 2–3, over 4. A total of 3046 incident hemodialysis patients enrolled from NHIRD were examined for an association between the separate scoring systems (CHADS2, CHA2DS2, and CCI score) and mortality.

Results

CHADS2 and CHA2DS2 scores revealed good predictive value for total mortality (CHADS2 AUC = 0.805; CHA2DS2 AUC = 0.790). However, the CCI score did not reveal a similarly satisfying result (AUC = 0.576).

Conclusions

Our results show that CHADS2 and CHA2DS2 scores can be applied for mortality prediction in incident hemodialysis patients.

Association between Hemodialysis Patient Outcomes and Compliance with KDOQI and KDIGO Targets for Mineral and Bone Metabolism

BACKGROUND

Increased mortality of hemodialysis (HD) patients is associated with chronic kidney disease-mineral and bone disorders (CKD-MBD), and therefore, their correction may improve patient survival. Differences in targets recommended by KDOQI and KDIGO CKD-MBD guidelines directed us to compare the relative numbers of patients achieving these targets and to examine possible associations between compliance with the targets and patient outcome.

METHODS

A total of 1,744 patients (61.2% males, aged 58.7 ± 12.5 years) dialyzed in 20 HD centers in Serbia were monitored for 3 years. The number of participants achieving KDOQI/KDIGO guideline targets for serum phosphorus, calcium, and iPTH was determined. The Cox proportional hazards model was used to select variables significantly associated with risk of time to death.

RESULTS

A majority of patients were dialyzed thrice weekly for 4 h; 86.3% of them used phosphate binders and 49.3% vitamin D3. Proportions of patients achieving KDOQI and KDIGO targets were 49.5 and 44.4% for phosphorus, 53.2 and 76.7% for calcium, 21 and 42.8% for iPTH. Multivariate Cox analysis selected serum phosphorus level outside the KDIGO target, as well as serum iPTH levels outside KDOQI and KDIGO targets as significant mortality predictors. Areas under the receiver operating characteristic curves showed that achievement of both guideline targets for iPTH had similar survival predictive values.

CONCLUSION

Serum phosphorus levels outside KDIGO targets and iPTH levels outside both KDOQI and KDIGO targets were associated with a significantly higher risk of death. These findings may be useful in the management of CKD-MBD and for establishing local guidelines.

Medical Nutrition Therapy for Chronic Kidney Disease Improves Biomarkers and Slows Time to Dialysis

OBJECTIVE

To investigate whether medical nutrition therapy (MNT) provided by a registered dietitian experienced in chronic kidney disease (CKD) slows the progression of disease and improves nutrition-related biomarkers.

DESIGN

Retrospective cohort study.

SUBJECTS

The cohort included 265 participants from a regional nephrology center in a rural state; 147 of who received MNT were compared to a group that did not receive MNT and had started dialysis over a 10-year period.

INTERVENTION

MNT by a registered dietitian with expertise in CKD.

MAIN OUTCOME MEASURE

Average time to dialysis, based on stage of CKD at baseline, was compared between groups. In addition, the effect of MNT on the change in biochemical measures for estimated glomerular filtration rate, blood urea nitrogen, albumin, CKD Mineral and Bone Disorder (MBD) markers (phosphorous, calcium, and intact parathyroid hormone) at baseline and at follow-up (dialysis initiation or most recent laboratories if dialysis was not started) was assessed.

RESULTS

MNT group had less of a decline in estimated glomerular filtration rate than the non-MNT group (0.3 vs. 9.9 mL/minute/1.73 m(2), respectively) a mean difference of 9.6 (P < 0.001). When adjusted for stage using linear regression, the mean difference was greater (11.4, P < .001). Using survival analysis and Cox proportional hazards regression, the non-MNT group was 3.15 more likely to initiate dialysis. Stratified by Stages 3 and 4 that hazard ratio increased (3.47 and 3.45, respectively). Albumin and markers of CKD-MBD were more likely to be within normal limits in the MNT group. The results indicate that better outcomes occur when MNT is given at CKD Stage 3 or 4 rather than CKD Stage 5.

CONCLUSIONS

Results suggest that people with CKD who received MNT were less likely to start dialysis and had improved nutritional biomarkers than participants who did not receive MNT.

Compliance with guidelines and predictors of mortality in hemodialysis. Learning from Serbia patients

OBJECTIVES

The aims of the study were to determine the percentage of patients on regular hemodialysis (HD) in Serbia failing to meet KDOQI guidelines targets and find out factors associated with the risk of time to death and the association between guidelines adherence and patient outcome.

METHODS

A cohort of 2153 patients on regular HD in 24 centers (55.7% of overall HD population) in Serbia were followed from January 2010 to December 2012. The percentage of patients failing to meet KDOQI guidelines targets of dialysis dose (Kt/V>1.2), hemoglobin (>110g/L), serum phosphorus (1.1-1.8mmol/L), calcium (2.1-2.4mmol/L) and iPTH (150-300pg/mL) was determined. Cox proportional hazards analysis was used to select variables significantly associated with the risk of time to death.

RESULTS

The patients were on regular HD for 5.3±5.3 years, dialyzed 11.8±1.9h/week. Kt/V<1.2 had 42.4% of patients, hemoglobin <110g/L had 66.1%, s-phosphorus <1.1mmol/L had 21.7% and >1.8mmol/L 28.6%, s-calcium <2.1mmol/L had 11.7% and >2.4mmol/L 25.3%, iPTH <150pg/mL had 40% and >300pg/mL 39.7% of patients. Using Cox model (adjustment for patient age, gender, duration of HD treatment) age, duration of HD treatment, hemoglobin, iPTH and diabetic nephropathy were selected as significant independent predictors of time to death. When targets of five examined parameters were included in Cox model, target for KtV, hemoglobin and iPTH were found to be significant independent predictors of time to death.

CONCLUSION

Substantial proportion of patients examined failed to meet KDOQI guidelines targets. The relative risk of time to death was associated with being outside the targets for Kt/V, hemoglobin and iPTH.

Renal transplantation in elderly patients. How to select the candidates to the waiting list?

Today, old age does not represent a formal contraindication to kidney transplantation. Rather, there is evidence that in elderly patients renal transplantation offers longer life expectancy and better quality of life in comparison with dialysis. Yet, the results of renal transplantation in recipients older than 65years are inferior to those observed in younger adults, death with functioning graft representing a major cause of failure. Therefore, the selection of aged patients is of paramount importance. Apart from the routine clinical and biological investigations, three aspects have been relatively neglected by the transplant community and may require a careful analysis in elderly candidates to transplantation: the presence and degree of frailty, the presence of comorbidities and the adherence to prescriptions. Although there are rapid and simple tests for assessing the degree of frailty in the elderly, there is no clear cut-off value to decide whether a patient should be accepted or not. With advanced age the prevalence and severity of cardiovascular events and other diseases tend to increase. The use of combined age-comorbidity indices may be helpful to identify patients at high risk of mortality. Another critical point is the poor unintentional adherence to treatment, often caused by forgetfulness and mild cognitive impairment. These drawbacks may be further enhanced by a high number of pills to take and by changes in the dosage or type of prescriptions. A careful screening of the presence and degree of frailty, comorbidity and poor compliance to treatment is highly recommended before admitting older candidates to the waiting list for transplantation.

Impact of patient characteristics and comorbidity profile on activation of patients on the kidney transplantation waiting list

BACKGROUND

The aim of this study was to examine which demographic and comorbidity factors affected the activation of patients with end-stage renal disease on the national kidney transplantation waiting list.

METHODS

This was a prospective cohort study across 13 transplantation centers in the United Kingdom from October 1, 2006 to September 30, 2007. Data were collected for all new adult patients (n = 1530) referred to the renal transplantation assessment clinic. The proportion of patients who were activated to the waiting list after a minimum one year follow-up was estimated. Factors influencing activation of patients on the waiting list were examined.

RESULTS

A total of 872 (58.9%) patients were activated to the transplantation waiting list. The likelihood of activation to the transplantation waiting list was lower in patients older than 65 years (P = .021), nonwhite ethnicity (P < .0001), smokers (P < .0001), and those in whom diabetes was the cause of renal failure (P = .004). Multivariate analysis showed that there was an adverse impact of comorbidity such as ischemic heart disease (P = .003), diabetes (P = .006), and peripheral vascular disease (P = .007) on the likelihood of activation to the waiting list.

CONCLUSION

Patient characteristics and comorbidity are associated with the probability of activation of patients to the waiting list.

Renal replacement therapy in Ukraine: epidemiology and international comparisons

BACKGROUND

Little is known about the status of renal replacement therapy (RRT) in the post-Soviet countries. We therefore investigated the epidemiology and treatment outcomes of RRT in Ukrainian patients and put the results into an international perspective.

METHODS

Data from the Ukrainian National Renal Registry for patients on RRT between 1 January 2010 and 31 December 2012 were selected. We calculated the incidence and prevalence of RRT per million population (pmp) and the 3-, 12- and 24-month patient survival using the Kaplan-Meier method and Cox regression.

RESULTS

There were 5985 prevalent patients on RRT on 31 December 2012 (131.2 pmp). Mean age was 46.5 ± 13.8 years, 56% men and 74% received haemodialysis (HD), while peritoneal dialysis and kidney transplantation both represented 13%. The most common cause of end-stage renal disease was glomerulonephritis (51%), while only 12% had diabetes. In 2012, 1129 patients started dialysis (incidence 24.8 pmp), with 80% on HD. Mean age was 48 ± 14 years, 58% men and 20% had diabetes. Three, 12- and 24-month patient survival on dialysis was 95.1%, 86.0% and 76.4%, respectively. The transplant rate in 2012 was 2.1 pmp.

CONCLUSIONS

The incidence and prevalence of RRT and the transplantation rate in Ukraine are among the lowest in Europe, suggesting that the need for RRT is not being met. Strategies to reduce the RRT deficit include the development and improvement of transplantation and home-based dialysis programmes. Further evaluation of the quality of Ukrainian RRT care is needed.

Survival prognosis after the start of a renal replacement therapy in the Netherlands: a retrospective cohort study

Background

There is no single model available to predict the long term survival for patients starting renal replacement therapy (RRT). The available models either predict survival on dialysis until transplantation, survival on the transplant waiting list, or survival after transplantation. The aim of this study was to develop a model that includes dialysis survival and survival after an eventual transplantation.

Methods

From the Dutch renal replacement registry, patients of 16 years of age or older were included if they started RRT between 1995 and 2005, still underwent RRT at baseline (90 days after the start of RRT) and were not registered at a non-renal organ transplant waiting list (N = 13868). A prediction model of 10-year patient survival after baseline was developed through multivariate Cox regression analysis, in one half of the research group. Age at start, sex, primary renal disease (PRD) and therapy at baseline were included as possible predictors. A sensitivity analysis has been performed to determine whether listing on the transplant waiting list should be added. The predictive performance of the model was internally validated. Calibration and discrimination were computed in the other half of the research group. Another sensitivity analysis was to assess whether the outcomes differed if the model was developed and tested in two geographical regions, which were less similar than the original development and validation group. No external validation has been performed.

Results

Survival probabilities were influenced by age, sex, PRD and therapy at baseline (p < 0.001). The calibration and discrimination both showed very reasonable results for the prediction model (C-index = 0.720 and calibration slope for the prognostic index = 1.025, for the 10 year survival). Adding registration on the waiting list for renal transplantation as a predictor did not improve the discriminative power of the model and was therefore not included in the model.

Conclusions

With the presented prediction model, it is possible to give a reasonably accurate estimation on the survival chances of patients who start with RRT, using a limited set of easily available data.

Variation in centre-specific survival in patients starting renal replacement therapy in England is explained by enhanced comorbidity information from hospitalization data

BACKGROUND

Unadjusted survival on renal replacement therapy (RRT) varies widely from centre to centre in England. Until now, missing data on case mix have made it impossible to determine whether this variation reflects genuine differences in the quality of care. Data linkage has the capacity to reduce missing data.

METHODS

Modelling of survival using Cox proportional hazards of data returned to the UK Renal Registry on patients starting RRT for established renal failure in England. Data on ethnicity, socioeconomic status and comorbidity were obtained by linkage to the Hospital Episode Statistics database, using data from hospitalizations prior to starting RRT.

RESULTS

Patients with missing data were reduced from 61 to 4%. The prevalence of comorbid conditions was remarkably similar across centres. When centre-specific survival was compared after adjustment solely for age, survival was below the 95% limit for 6 of 46 centres. The addition of variables into the multivariable model altered the number of centres that appeared to be 'outliers' with worse than expected survival as follows: ethnic origin four outliers, socioeconomic status eight outliers and year of the start of RRT four outliers. The addition of a combination of 16 comorbid conditions present at the start of RRT reduced the number of centres with worse than expected survival to one.

CONCLUSIONS

Linked data between a national registry and hospital admission dramatically reduced missing data, and allowed us to show that nearly all the variation between English renal centres in 3-year survival on RRT was explained by demographic factors and by comorbidity.

Increased risk of fatal infections in women starting peritoneal dialysis

BACKGROUND AND OBJECTIVES

Although cardiovascular disease (CVD) is an important cause of morbidity and mortality in patients with end-stage renal disease, non-CVD causes account for more than 50% of total deaths. We previously showed that, compared with men, women starting dialysis-- both hemodialysis and peritoneal dialysis (PD)--have higher non-CVD mortality rates. Here, we evaluate sex-specific outcomes in a large cohort of incident PD patients.

METHODS

Incident de novo PD patients from the Andalusian SICATA Registry for 1999 - 2010, with follow-up until 31 December 2010 or up to 5 years, were investigated for fatal outcomes. Causes of death were extracted from medical records. The analysis used traditional and competing-risk Cox models for all-cause and cause-specific mortality in men and women, correcting in the competing-risk models for the events of kidney transplantation and transfer to hemodialysis.

RESULTS

A total of 1458 patients (57% men; mean overall age: 55.3 ± 17.0 years) initiated PD in Andalusia during the study period. During follow-up, 350 deaths, 355 renal transplantation procedures, and 331 transfers to hemodialysis were recorded. Vascular disease and diabetic nephropathy were the most frequent causes of kidney failure in men; other causes were more common in women. In the traditional Cox model, both sexes showed a similar all-cause mortality risk [crude hazard ratio (HR): 0.90; 95% confidence interval (CI): 0.72 to 1.12]. However, with respect to specific causes of death, women showed a borderline lower risk of both CVD (crude HR: 0.71; 95% CI: 0.50 to 0.99) and non-CVD mortality from other than infection (crude HR: 0.81; 95% CI: 0.57 to 1.15). In contrast, the risk of death from infection was almost doubled in women compared with men (crude HR: 1.92; 95% CI: 1.15 to 3.20), a finding that held true after multivariate adjustment for age, primary renal disease, period of inclusion, and initial PD modality (adjusted HR: 1.76; 95% CI: 1.03 to 3.01). This result was confirmed even taking into consideration the competing events of kidney transplantation and transfer to hemodialysis.

CONCLUSIONS

Compared with men starting PD, women starting PD are at higher risk of mortality from infection. More stringent screening measures and corrective efforts in women might be indicated.

The role of peritoneal dialysis in modern renal replacement therapy

Most patients starting dialysis can choose between peritoneal dialysis and haemodialysis. There is little evidence proving that one form of dialysis is better than the other; although there may be an early advantage to peritoneal dialysis (PD) in young patients with residual function this effect is short-lived. Technique failure develops after years on PD so dialysis modality will often change during a long dialysis career. Quality of life studies, which must be interpreted carefully, indicate that patients require information about the impact of dialysis on their lifestyle as well as health-related outcomes so that they can choose the most suitable dialysis modality. Increasing numbers of frail elderly patients are starting dialysis; support in the home by nursing staff may facilitate the use of PD in this group. In the UK guidelines prioritise the patient's choice of dialysis modality (where feasible) based on good quality predialysis education. Cost of treatment is generally lower on PD, which is particularly recommended for patients with residual renal function and few comorbidities.

Association between pre-transplant dialysis modality and patient and graft survival after kidney transplantation

BACKGROUND

Previous studies have found inconsistent associations between pre-transplant dialysis modality and subsequent post-transplant survival. We aimed to examine this relationship using the instrumental variable method and to compare the results with standard Cox regression.

METHODS

We included 29 088 patients (age >20 years) from 16 European national or regional renal registries who received a first kidney transplant between 1 January 1999 and 31 December 2008 and were on dialysis before transplantation for a period between 90 days and 10 years. Standard multivariable Cox regression examined the association of individually assigned pre-transplant dialysis modality with post-transplant patient and graft survival. To decrease confounding-by-indication through unmeasured factors, we applied the instrumental variable method that used the case-mix adjusted centre percentage of peritoneal dialysis (PD) as predictor variable.

RESULTS

Standard analyses adjusted for age, sex, primary renal disease, donor type, duration of dialysis, year of transplantation and country suggested that PD before transplantation was associated with better patient [hazard ratio, HR (95% CI) = 0.83 (0.76-0.91)] and graft survival (HR (95% CI) 0.90 (0.84-0.96)) when compared with haemodialysis (HD). In contrast, the instrumental variable analysis showed that a 10% increase in the case-mix adjusted centre percentage of patients on PD was neither associated with post-transplant patient survival [HR (95% CI = 1.00 (0.97-1.04)] nor with graft survival [HR (95% CI) = 1.01 (0.98-1.04)].

CONCLUSIONS

The instrumental variable method failed to confirm the associations found in standard Cox regression between pre-transplant dialysis modality and patient and graft survival after transplantation. The lack of association in instrumental variable analysis may be due to better control of residual confounding.

Impact of a modified data capture period on Liu comorbidity index scores in Medicare enrollees initiating chronic dialysis

Background

The Liu Comorbidity Index uses the United States Renal Data System (USRDS) to quantify comorbidity in chronic dialysis patients, capturing baseline comorbidities from days 91 through 270 after dialysis initiation. The 270 day survival requirement results in sample size reductions and potential survivor bias. An earlier and shorter time-frame for data capture could be beneficial, if sufficiently similar comorbidity information could be ascertained.

Methods

USRDS data were used in a retrospective observational study of 70,114 Medicare- and Medicaid-eligible persons who initiated chronic dialysis during the years 2000–2005. The Liu index was modified by changing the baseline comorbidity capture period to days 1–90 after dialysis initiation for persons continuously enrolled in Medicare. The scores resulting from the original and the modified comorbidity indices were compared, and the impact on sample size was calculated.

Results

The original Liu comorbidity index could be calculated for 75% of the sample, but the remaining 25% did not survive to 270 days. Among 52,937 individuals for whom both scores could be calculated, the mean scores for the original and the modified index were 7.4 ± 4.0 and 6.4 ± 3.6 points, respectively, on a 24-point scale. The most commonly calculated difference between scores was zero, occurring in 44% of patients. Greater comorbidity was found in those who died before 270 days.

Conclusions

A modified version of the Liu comorbidity index captures the majority of comorbidity in persons who are Medicare-enrolled at the time of chronic dialysis initiation. This modification reduces sample size losses and facilitates inclusion of a sicker portion of the population in whom early mortality is common.

Outcomes of male patients with Alport syndrome undergoing renal replacement therapy

BACKGROUND AND OBJECTIVES

Patients with the hereditary disease Alport syndrome commonly require renal replacement therapy (RRT) in the second or third decade of life. This study compared age at onset of RRT, renal allograft, and patient survival in men with Alport syndrome receiving various forms of RRT (peritoneal dialysis, hemodialysis, or transplantation) with those of men with other renal diseases.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with Alport syndrome receiving RRT identified from 14 registries in Europe were matched to patients with other renal diseases. A linear spline model was used to detect changes in the age at start of RRT over time. Kaplan-Meier method and Cox regression analysis were used to examine patient and graft survival.

RESULTS

Age at start of RRT among patients with Alport syndrome remained stable during the 1990s but increased by 6 years between 2000-2004 and 2005-2009. Survival of patients with Alport syndrome requiring dialysis or transplantation did not change between 1990 and 2009. However, patients with Alport syndrome had better renal graft and patient survival than matched controls. Numbers of living-donor transplantations were lower in patients with Alport syndrome than in matched controls.

CONCLUSIONS

These data suggest that kidney failure in patients with Alport syndrome is now being delayed compared with previous decades. These patients appear to have superior patient survival while undergoing dialysis and superior patient and graft survival after deceased-donor kidney transplantation compared with patients receiving RRT because of other causes of kidney failure.

Exploring the association between macroeconomic indicators and dialysis mortality

BACKGROUND AND OBJECTIVES

Mortality on dialysis varies greatly worldwide, with patient-level factors explaining only a small part of this variation. The aim of this study was to examine the association of national-level macroeconomic indicators with the mortality of incident dialysis populations and explore potential explanations through renal service indicators, incidence of dialysis, and characteristics of the dialysis population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Aggregated unadjusted survival probabilities were obtained from 22 renal registries worldwide for patients starting dialysis in 2003-2005. General population age and health, macroeconomic indices, and renal service organization data were collected from secondary sources and questionnaires. Linear modeling with log-log transformation of the outcome variable was applied to establish factors associated with survival on dialysis.

RESULTS

Two-year survival on dialysis ranged from 62.3% in Iceland to 89.8% in Romania. A higher gross domestic product per capita (hazard ratio=1.02 per 1000 US dollar increase), a higher percentage of gross domestic product spent on healthcare (1.10 per percent increase), and a higher intrinsic mortality of the dialysis population (i.e., general population-derived mortality risk of the dialysis population in that country standardized for age and sex; hazard ratio=1.04 per death per 10,000 person years) were associated with a higher mortality of the dialysis population. The incidence of dialysis and renal service indicators were not associated with mortality on dialysis.

CONCLUSIONS

Macroeconomic factors and the intrinsic mortality of the dialysis population are associated with international differences in the mortality on dialysis. Renal service organizational factors and incidence of dialysis seem less important.

Incidence of invasive breast cancer in the presence of competing mortality: the Canadian National Breast Screening Study

Mortality due to causes other than breast cancer is a potential competing risk which may alter the incidence probability of breast cancer and as such should be taken into account in predictive modelling. We used data from the Canadian National Breast Screening Study (CNBSS), which consist of two randomized controlled trials designed to evaluate the efficacy of mammography among women aged 40-59. The participants in the CNBSS were followed up for incidence of breast cancer and mortality due to breast cancer and other causes; this allowed us to construct a breast cancer risk prediction model while taking into account mortality for the same study population. In this study, we use 1980-1989 as the study period. We exclude the prevalent cancers from the CNBSS to estimate the probability of developing breast cancer, given the fact that women were cancer-free at the beginning of the follow-up. By the end of 1989, from 89,434 women, 944 (1.1 %) were diagnosed with invasive breast cancer, 922 (1.0 %) died from causes other than breast cancer, and 87,568 (97.9 %) were alive and not diagnosed with invasive breast cancer. We constructed a risk prediction model for invasive breast cancer based on 39 risk factors collected at the time of enrolment or the initial physical examination of the breasts. Age at entry (HR 1.07, 95 % CI 1.05-1.10), lumps ever found in left or right breast (HR 1.92, 95 % CI 1.19-3.10), abnormality in the left breast (HR 1.26, 95 % CI 1.07-1.48), history of other breast disease, family history of breast cancer score (HR 1.01, 95 % CI 1.00-1.01), years menstruating (HR 1.02, 95 % CI 1.01-1.03) and nulliparity (HR 1.70, 95 % CI 1.23-2.36) are the model's predictors. We investigated the effects of time-dependent factors. The model is well calibrated with a moderate discriminatory power (c-index 0.61, 95 % CI 0.59-0.63); we use it to predict the 9-year risk of developing breast cancer for women of different age groups. As an example, we estimated the probability of invasive cancer at 5 years after enrolment to be 0.00448, 0.00556, 0.00691, 0.00863, and 0.01034, respectively, for women aged 40, 45, 50, 55, and 59, all of whom had never noted lumps in their breasts, had 32 years of menstruating, 1-2 live births, no other types of breast disease and no abnormality found in their left breasts. The results of this study can be used by clinicians to identify women at high risk of breast cancer for screening intervention and to recommend a personalized intervention plan. The model can be also utilized by a woman as a breast cancer risk prediction tool.

Utilization Patterns of IV Iron and Erythropoiesis Stimulating Agents in Anemic Chronic Kidney Disease Patients: A Multihospital Study

Intravenous (IV) iron and Erythropoiesis Stimulating Agents (ESAs) are recommended for anemia management in chronic kidney disease (CKD). This retrospective cohort study analyzed utilization patterns of IV iron and ESA in patients over 18 years of age admitted to University Health System Hospitals with a primary or secondary diagnosis of CKD between January 1, 2006 to December 31, 2008. A clustered binomial logistic regression using the GEE methodology was used to identify predictors of IV iron utilization. Only 8% (n = 6678) of CKD patients on ESA therapy received IV iron supplementation in university hospitals. Those receiving iron used significantly less amounts of ESAs. Patient demographics (age, race, primary payer), patient clinical conditions (admission status, severity of illness, dialysis status), and physician specialty were identified as predictors of IV iron use in CKD patients. Use of IV iron with ESAs was low despite recommendations from consensus guidelines. The low treatment rate of IV iron represents a gap in treatment practices and signals an opportunity for healthcare improvement in CKD anemic patients.

Decline in glomerular filtration rate during pre-dialysis phase and survival on chronic renal replacement therapy

BACKGROUND

Estimated glomerular filtration rate (eGFR) is widely used in follow-up and assessment of patients before start of chronic renal replacement therapy (RRT). Reported data on impact of eGFR decline pattern during pre-dialysis phase on consequent survival on RRT are, however, non-existent.

METHODS

Using the database of the Finnish Registry for Kidney Diseases, we conducted a cohort study of all incident adult patients (n = 457) entering chronic RRT in Finland in 1998, with follow-up until 31 December 2008. We included those (n = 319) with three serum creatinine measurements (at ∼12 and 3 months and 1 to 2 weeks prior to RRT start) and calculated their slopes of eGFR using the modification of diet in renal disease formula. According to eGFR slopes (in mL/min/1.73m(2)/year), patients were divided into tertiles: most rapid (>8.5, n = 107), intermediate (3.4-8.5, n = 107) and slowest decline (<3.4, n = 105).

RESULTS

Median survival time was 5.6 (95% confidence interval 4.2-7.0) years. Compared to the patient group with the slowest eGFR decline, age- and gender-adjusted relative risk of death was 1.1 (0.8-1.5) in the intermediate group and 1.7 (1.2-2.4, P = 0.002) in the most rapid decline group. When further adjusting for kidney disease diagnosis, comorbidities, use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, body mass index, blood haemoglobin and serum albumin, the association was no longer significant.

CONCLUSIONS

Rapid decline in eGFR before entering chronic RRT associates with increased mortality on RRT. The elevated mortality appears to be caused by known risk factors for death on RRT.

Comorbidities and survival of patients with type 1 diabetes on renal replacement therapy

AIMS/HYPOTHESIS

Comorbidities are frequent among type 1 diabetes patients on renal replacement therapy, yet the effect of comorbidities on survival is unknown. Our aim was to estimate this effect.

METHODS

An incident cohort of all patients with type 1 diabetes entering chronic renal replacement therapy (n = 656) in Finland between 2000 and 2008 was followed until death or the end of follow-up on 31 December 2008. All data were obtained from the Finnish Registry for Kidney Diseases, which collects information on comorbidities at the start of renal replacement therapy. The main outcome measure was relative risk of death according to comorbidities.

RESULTS

At start of renal replacement therapy, 22% of the patients with type 1 diabetes had coronary artery disease, 19% peripheral vascular disease, 11% cerebrovascular disease, 33% left ventricular hypertrophy and 7% heart failure. All these comorbidities were significant predictors of death in univariate analyses (RR 1.6-4.9). The 5 year survival probability of patients without comorbidities was 74%, while it was 56% and 37%, respectively, for those with one or more than one comorbidity. When the comorbidities were studied in a multivariate model, adjusting for age and sex, peripheral vascular disease (RR 1.9), left ventricular hypertrophy (RR 1.7) and heart failure (RR 2.5) remained independent risk factors for death. Calculations indicated that one-third of deaths in the study population could be attributed to comorbidities.

CONCLUSIONS/INTERPRETATION

Among patients with type 1 diabetes entering renal replacement therapy, comorbidities are common and strong predictors of death. Therefore, it is essential to identify and adequately treat comorbidities.

Time-dependent impact of diabetes on the mortality of patients on renal replacement therapy: a population-based study in Germany (2002-2009)

AIMS

To estimate the impact of diabetes on the mortality of patients with incident renal replacement therapy (RRT).

METHODS

We assessed the mortality of 544 incident RRT patients aged ≥ 30 years between 2002 and 2009 (57.9% men, mean age 70.3 years, 49.6% patients with diabetes) by analyzing the data of all dialysis centers covering a German region. We compared the estimated time-dependent hazard ratios of patients with and without diabetes by using the Cox proportional-hazards regression model.

RESULTS

Overall, 319 patients had died (158 diabetic), approximately 50% after 3 years. Up to about 3 years, the mortality rate was lower in diabetic than in nondiabetic patients. Thereafter, the survival curves crossed (interaction diabetes × time, p = 0.002; adjusted hazard ratios for diabetes: baseline, 0.66; year 1, 0.84; year 2, 1.05; year 3, 1.33; year 4, 1.68). The results were similar in men and women; however, the interaction of diabetes and time was significant only in men (p = 0.004). Further significant risk factors of mortality were age, sex, initial central venous catheter, cardiovascular disease, and malignancy.

CONCLUSIONS

In this population-based study, the influence of diabetes was time-dependent, with a lower mortality in diabetic versus non-diabetic patients in the first three years but a higher mortality in these patients after 3 years. Results were similar in men and women.

Patterns and effects of missing comorbidity data for patients starting renal replacement therapy in England, Wales and Northern Ireland

BACKGROUND

Renal Registries play a key role in assessing quality of care and outcomes of renal replacement therapy and comparisons of outcomes between groups should adjust for differences in comorbidities. This study aimed to describe patterns of missing comorbidity data and differences in survival between patients with comorbidity data returned and those with missing comorbidity data.

METHODS

Trends in comorbidity data returns by year (1998-2006) and within centres were examined using descriptive statistics. Survival of patients was described using Kaplan-Meier graphs (log-rank tests) and hazard ratios were calculated using Cox proportional hazard models. Last follow-up was at 31 December 2007. A range of sensitivity analyses were carried out, including multiple imputation.

RESULTS

Among 34,059 patients, there were 62% who had no comorbidity data. The completeness of comorbidity data increased markedly from 17% in 1998 to 47% in 2003, but had fallen back to 37% by the year 2006. Those with a missing comorbidity generally do considerably worse than those without the comorbidity and in most cases more closely follow the survival curve of those with the comorbidity. Multiple imputation analysis suggested that those with missing information on comorbidity have higher prevalence of comorbidity than seen in those with available data. Treating missing comorbidity entries as indication of absent comorbidity (i.e. a tick only if yes policy) would lead to an attenuation of the effect of comorbidity on survival.

CONCLUSIONS

Missing data lead to difficulties in performing between centre comparisons. A 'tick if present policy' in comorbidity data collection should be discouraged. Much more work is needed to fully understand why levels of missing comorbidity data are so high and to identify strategies to improve recording.

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.

Hemoglobin variability does not predict mortality in European hemodialysis patients

Patients with CKD exhibit significant within-patient hemoglobin (Hb) level variability, especially with the use of erythropoiesis stimulating agents (ESAs) and iron. Analyses of dialysis cohorts in the United States produced conflicting results regarding the association of Hb variability with patient outcomes. Here, we determined Hb variability in 5037 European hemodialysis (HD) patients treated over 2 years to identify predictors of high variability and to evaluate its association with all-cause and cardiovascular disease (CVD) mortality. We assessed Hb variability with various methods using SD, residual SD, time-in-target (11.0 to 12.5 g/dl), fluctuation across thresholds, and area under the curve (AUC). Hb variability was significantly greater among incident patients than prevalent patients. Compared with previously described cohorts in the United States, residual SD was similar but fluctuations above target were less frequent. Using logistic regression, age, body mass index, CVD history, dialysis vintage, serum albumin, Hb, angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) use, ESA use, dialysis access type, dialysis access change, and hospitalizations were significant predictors of high variability. Multivariable adjusted Cox regression showed that SD, residual SD, time-in-target, and AUC did not predict all-cause or CVD mortality during a median follow-up of 12.4 months (IQR: 7.7 to 17.4). However, patients with consistently low levels of Hb (<11 g/dl) and those who fluctuated between the target range and <11 g/dl had increased risks for death (RR 2.34; 95% CI: 1.24 to 4.41 and RR 1.74; 95% CI: 1.00 to 3.04, respectively). In conclusion, although Hb variability is common in European HD patients, it does not independently predict mortality.

Is the inverse relation between blood pressure and mortality normalized in 'low-risk' dialysis patients?

BACKGROUND

SBP is a potent predictor of mortality. However, in hemodialysis populations, the relation between SBP and mortality is a matter of debate. In hemodialysis patients, low SBP rather than high SBP has been related to mortality. It has been suggested that this inverse relationship is 'normalized' in dialysis patients with a low mortality risk and that short-term and long-term effects of SBP might differ.

DESIGN

We analyzed the relationship of mortality and SBP in 1111 incident hemodialysis patients participating in the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD) cohort. Long-term and short-term effects were studied in patients with (n = 452) and without (n = 659) cardiovascular comorbidity.

RESULTS

Maximal follow-up was 7.5 years; 477 patients died. Two-year mortality rate was 44 and 20% in the groups with and without cardiovascular comorbidity, respectively. Both in the whole group and in both subpopulations, low SBP was associated with an increased mortality. The increased mortality risk associated with low SBP was especially observed as a short-term effect (6 months). In neither group did we observe a significant long-term effect between SBP and mortality.

CONCLUSION

Our data do not support the hypothesis that the inverse relation between SBP and mortality is 'normalized' in a dialysis population with a low absolute mortality risk. Neither do our data support the hypothesis that elevated SBP increases mortality risk in the long-term.

Prognostic Survival Factors in Elderly Renal Failure Patients Treated with Peritoneal Dialysis: A Nine-Year Retrospective Study

Background

Few studies specifically investigating elderly patients on peritoneal dialysis (PD) have been conducted and great uncertainty remains on the factors involved in the vital prognosis. The objective of this study was to describe our population of patients aged 75 years or older at the time PD was initiated and to study their survival in terms of the relevant nephro-geriatric criteria inventoried at the beginning of treatment.

Methods

We retrospectively analyzed the data of all the elderly patients that began first-line PD in our center between 1 January 1997 and 31 July 2006 ( n = 112).

Results

Mean duration of survival on PD was 19.6 ± 13.9 months; by the end of the study 87 patients had died and 7 had been transferred to hemodialysis. The Cox model multivariate analysis of survival allowed us to select 5 independent predictive variables that had a considerable impact on survival: absence of nephrologic care before dialysis, associated comorbidities (Charlson Comorbidity Index), loss of physical and/or mental autonomy (AGGIR group), and polymedication. Above and beyond the weight of these clinical variables, institutionalization or, more generally, social isolation was a determining factor for the duration of survival in PD.

Conclusion

Any patient considered for peritoneal dialysis should be evaluated by a multidisciplinary team in collaboration with geriatric specialists for both the overall medical situation and the social and family environment.

Outcomes associated with in-center nocturnal hemodialysis from a large multicenter program

BACKGROUND AND OBJECTIVES

The objective of this study was to evaluate epidemiology and outcomes of a large in-center nocturnal hemodialysis (INHD) program.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This case-control study compared patients who were on thrice-weekly INHD from 56 Fresenius Medical Care, North America facilities with conventional hemodialysis patients from 244 facilities within the surrounding geographic area. All INHD cases and conventional hemodialysis control subjects who were active as of January 1, 2007, were followed until December 31, 2007, for evaluation of mortality and hospitalization.

RESULTS

As of January 1, 2007, 655 patients had been on INHD for 51 +/- 73 d. Patients were younger, there were more male and black patients, and vintage was longer, but they had less diabetes compared with 15,334 control subjects. Unadjusted hazard ratio was 0.59 for mortality and 0.76 for hospitalization. After adjustment for case mix and access type, only hospitalization remained significant. Fewer INHD patients were hospitalized (48 versus 59%) with a normalized rate of 9.6 versus 13.5 hospital days per patient-year. INHD patients had greater interdialytic weight gains but lower BP. At baseline, hemoglobin values were similar, whereas albumin and phosphorus values favored INHD. Mean equilibrated Kt/V was higher in INHD patients related to longer treatment time, despite lower blood and dialysate flow rates.

CONCLUSIONS

Patients who were on INHD exhibited excellent quality indicators, with better survival and lower hospitalization rates. The relative contributions of patient selection versus effect of therapy on outcomes remain to be elucidated in prospective clinical trials.

Key comorbid conditions that are predictive of survival among hemodialysis patients

BACKGROUND AND OBJECTIVES

Abstracting information about comorbid illnesses from the medical record can be time-consuming, particularly when a large number of conditions are under consideration. We sought to determine which conditions are most prognostic and whether comorbidity continues to contribute to a survival model once laboratory and clinical parameters have been accounted for.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Comorbidity data were abstracted from the medical records of Dialysis Outcomes and Practice Pattern Study (DOPPS) I, II, and III participants using a standardized questionnaire. Models that were composed of different combinations of comorbid conditions and case-mix factors were compared for explained variance (R(2)) and discrimination (c statistic).

RESULTS

Seventeen comorbid conditions account for 96% of the total explained variance that would result if 45 comorbidities that were expected to be predictive of survival were added to a demographics-adjusted survival model. These conditions together had more discriminatory power (c statistic 0.67) than age alone (0.63) or serum albumin (0.60) and were equivalent to a combination of routine laboratory and clinical parameters (0.67). The strength of association of the individual comorbidities lessened when laboratory/clinical parameters were added, but all remained significant. The total R(2) of a model adjusted for demographics and laboratory/clinical parameters increased from 0.13 to 0.17 upon addition of comorbidity.

CONCLUSIONS

A relatively small list of comorbid conditions provides equivalent discrimination and explained variance for survival as a more extensive characterization of comorbidity. Comorbidity adds to the survival model a modest amount of independent prognostic information that cannot be substituted by clinical/laboratory parameters.

Anemia management and association of race with mortality and hospitalization in a large not-for-profit dialysis organization

BACKGROUND

The optimal hemoglobin target and possible toxicity of epoetin therapy in hemodialysis patients are controversial. Previous studies suggest that African American patients use higher doses of epoetin and have better survival compared with white hemodialysis patients.

STUDY DESIGN

Retrospective longitudinal cohort.

SETTING & PARTICIPANTS

Epoetin-exposed incident hemodialysis patients (N = 12,733; African Americans, n = 4,801; white, n = 7,386) treated in Dialysis Clinic Inc facilities during 2000 to 2006.

PREDICTORS

Hemoglobin, epoetin, iron.

OUTCOMES

Mortality, hospitalization.

MEASUREMENTS

Proportional hazards models with time-varying covariates.

RESULTS

Hemoglobin concentrations less than 10 g/dL in whites and less than 11 g/dL in African Americans were associated with increased mortality and hospitalization versus the referent hemoglobin level of 11 to 11.9 g/dL. Hemoglobin levels of 13 g/dL or greater in whites were associated with decreased noncardiovascular mortality. Six-month cumulative epoetin doses of 20,000 U/wk or greater were associated with increased mortality and hospitalization versus the referent group (8,000 to 12,499 U/wk). Epoetin doses less than 8,000 U/wk were associated with decreased risk. Higher epoetin doses were associated with increased mortality at hemoglobin concentrations of 10 to 12.9 g/dL and with increased hospitalization at all hemoglobin concentrations of 10 g/dL or greater. Higher epoetin doses were associated with increased mortality and hospitalization within each tertile of serum albumin concentration. These patterns did not differ by race.

LIMITATIONS

Treatment-by-indication bias and unidentified confounders cannot be excluded. Small sample sizes in the highest and lowest hemoglobin strata decrease statistical power.

CONCLUSIONS

Relationships between hemoglobin concentration and mortality differed between African Americans and whites. Additionally, the relationship of lower mortality with greater achieved hemoglobin concentration seen in white patients was observed for all-cause, but not cardiovascular, mortality. A higher cumulative epoetin dose was associated with worse outcomes, even in patients with albumin levels greater than 4 g/dL. There were no statistically significant interactions between race and epoetin dose. Further studies are needed to confirm and to define the mechanism of these findings.

Malnutrition-inflammation complex syndrome and hepatitis C in maintenance hemodialysis patients

Protein-energy malnutrition and inflammation are among the leading causes of poor outcome in hemodialysis patients. Hepatitis C virus (HCV) infection is accompanied by elevated proinflammatory mediators, also found in dialysis patients with malnutrition-inflammation complex syndrome. We aimed to study the rate and characteristics of malnutrition-inflammation complex syndrome (MICS) in hemodialysis patients, especially those with hepatitis C. The study included 147 patients (mean age 55.1 +/- 12.9 years), 24.5% of whom were HCV-positive, undergoing adequate hemodialysis three times a week for the last 52.7 +/- 52.5 months. Parameters of nutrition and inflammation were investigated to evaluate MICS. HCV-positive vs. HCV-negative patients had significantly higher hematocrit (29.6 +/- 4.5 g/dL vs. 28.1 +/- 4.3, P < 0.05), uric acid (345.8 +/- 96.5 vs. 321.3 +/- 118.8 micromol/mL, P < 0.05), aspartate aminotransferase (AST, also known as serum glutamic oxaloacetic transaminase [SGOT]) (23.3 +/- 14.9 vs. 17.8 +/- 9 U/L, P < 0.008), alanine aminotransferase (ALT, also known as serum glutamic pyruvic transaminase [SGPT]) (41.2 +/- 28.7 vs. 26.6 +/- 17.1 U/L, P < 0.0003), serum creatinine (980.4 +/- 219.1 vs. 888.4 +/- 202.9 micromol/mL, P < 0.022), intact parathyroid hormone (329.7 +/- 630.5 vs. 110.2 +/- 145.3 pg/mL, P < 0.002), malnutrition-inflammation score (7.4 +/- 5.2 vs. 5.6 +/- 4.1, P < 0.038), and Charlson comorbidity index (4.5 +/- 1.5 vs. 4 +/- 1.4, P < 0.05). MICS had a prevalence of 20-40% in our study. HCV-positive patients had a significantly higher prevalence of MICS than HCV-negative patients (30-40% vs. 20-30%).

Clinical outcomes in elderly kidney transplant recipients are related to acute rejection episodes rather than pretransplant comorbidity

BACKGROUND

Deciding whether an elderly patient with end-stage renal disease is a candidate for kidney transplantation can be difficult. We aimed to evaluate pre- and early posttransplant risk factors that could predict outcome in elderly kidney recipients.

METHODS

Data from all elderly (>or= 70 years, n=354), senior (60-69 years, n=577), and control (45-54 years, n=563) patients receiving their first kidney transplant at our center from 1990 to 2005 were retrieved. Patient and graft survival were analyzed in a Cox model addressing the common risk factors including Charlson comorbidity index (CCI), pretransplant dialysis time, and early acute rejection episodes.

RESULTS

Acute rejection in the first 90 days, Hazard ratio (HR) 1.74 (1.34-2.25); time on dialysis, HR 1.02 (1.01-1.03) per month; and donor age more than 60 years, HR 1.52 (1.14-2.01) predicted mortality in the elderly. CCI score did not predict mortality in the elderly, HR 1.05 (0.98-1.12); but did so both in senior, HR 1.17 (1.08-1.27) and control recipients, HR 1.33 (1.19-1.48). Delayed graft function, HR 3.69 (2.01-6.79); donor age more than 60 years, HR 2.42 (1.30-4.49); and presence of human leukocyte antigen antibodies, HR 3.96 (1.38-11.37) were independent predictors for death-censored graft loss in the elderly.

CONCLUSION

Adequate immunosuppression with low frequency of rejection episodes improves the outcome for elderly kidney recipients as does a reduction of time on dialysis. CCI score at transplantation does not seem helpful in the selection of elderly patients for kidney transplantation but plays a significant role in patients under 70 years of age.

Hemodialysis facility-based quality-of-care indicators and facility-specific patient outcomes

BACKGROUND

We evaluated whether incremental achievement of up to 8 facility quality goals was associated with improvement in facility-specific mortality and hospitalization rates.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

1,085 Fresenius Medical Care, North America facilities providing hemodialysis (HD) for 25 or more patients during January 2006.

MEASUREMENTS

The facility average for the period up to December 31, 2006, was used to determine achievement of each goal for equilibrated Kt/V, missed HD treatments, hemoglobin level, bicarbonate level, albumin level, phosphorus level, fistulae, and HD catheters. Linear regression models were used to relate facility-wide achievement of goals with facility-specific hospital days and standardized mortality ratios.

RESULTS

Most facilities (64%) achieved 2 to 4 of 8 goals, with only 8% meeting more than 5 quality goals. Achieving more than 5 goals averaged 3.5 fewer hospital days/patient-year and 20% lower standardized mortality ratios (all P < 0.001). The incremental number of goals met also was associated with improvement in facility mortality (P < 0.001) and hospital days (P < 0.001). Catheter and albumin level goals were achieved least (6% and 9% of facilities, respectively), but they had the best outcomes. Facilities achieving more than 5 goals had older patients (64.0 versus 61.5 years; P < 0.001), fewer African American patients (16% versus 38%; P < 0.001), and fewer women (44% versus 46%; P = 0.003) compared with the average.

LIMITATIONS

Observational design with residual confounding from unmeasured patient-, facility-, and treatment-related factors.

CONCLUSIONS

Achieving more facility quality goals was significantly associated with better facility-based measurements of patient outcomes. Although these results do not establish a causal relationship, findings agree with the present practice of monitoring facility performance for continuous quality improvement.

The outcomes of continuous ambulatory and automated peritoneal dialysis are similar

Recent reports indicate a decreased mortality risk for patients on chronic peritoneal dialysis in the United States. We sought to determine whether a higher use of automated versus continuous ambulatory peritoneal dialysis was associated with this improvement. Analyses were carried out using data from the United States Renal Data System on 66,381 incident patients on chronic peritoneal dialysis in the years 1996-2004 that were adjusted for demographic, clinical, laboratory and dialysis facility characteristics. Patients were followed until the time of transfer to other modes of dialysis, transplant, or death, whichever occurred first, or until their last follow-up through September 2006. Over time, the risks were substantially reduced such that the adjusted hazard ratios for death or technique failure of these patients in the 2002-2004 period were 0.55 (0.53, 0.57) and 0.62 (0.59, 0.64), respectively, compared with those of incident patients during the years 1996-1998. The risk improvements for both modes of dialysis were, however, found to be similar. Under intent-to-treat, time-dependent, and as-treated analysis, there was little or no difference in risk for death or in technique failure. Thus, the improved chronic peritoneal dialysis outcomes cannot be attributed to a greater use of automated peritoneal dialysis.