Comorbidity assessment in hemodialysis and peritoneal dialysis using the index of coexistent disease

Discrepancy in responses to the surprise question between hemodialysis nurses and physicians, with focus on patient clinical characteristics: A comparative study

INTRODUCTION

The surprise question (SQ) "Would I be surprised if this patient died within the next xx months" can be used by different professions to foresee the need of serious illness conversations in patients approaching end of life. However, little is known about the different perspectives of nurses and physicians in responses to the SQ and factors influencing their appraisals. The aim was to explore nurses' and physicians' responses to the SQ regarding patients on hemodialysis, and to investigate how these answers were associated with patient clinical characteristics.

METHODS

This comparative cross-sectional study included 361 patients for whom 112 nurses and 15 physicians responded to the SQ regarding 6 and 12 months. Patient characteristics, performance status, and comorbidities were obtained. Cohen's kappa was used to analyze the interrater agreement between nurses and physicians in their responses to the SQ and multivariable logistic regression was applied to reveal the independent association to patient clinical characteristics.

FINDINGS

Proportions of nurses and physicians responding to the SQ with "no, not surprised" was similar regarding 6 and 12 months. However, there was a substantial difference concerning which specific patient the nurses and physicians responded "no, not surprised", within 6 (κ = 0.366, p < 0.001, 95% CI = 0.288-0.474) and 12 months (κ = 0.379, p < 0.001, 95% CI = 0.281-0.477). There were also differences in the patient clinical characteristics associated with nurses' and physicians' responses to the SQ.

DISCUSSION

Nurses and physicians have different perspectives in their appraisal when responding to the SQ for patients on hemodialysis. This may reinforce the need for communication and discussion between nurses and physicians to identify the need of serious illness conversations in patients approaching the end of life, in order to adapt hemodialysis care to patient preferences and needs.

Physical Resilience Phenotype Trajectories in Incident Hemodialysis: Characterization and Mortality Risk Assessment

Introduction

Methods

Results

Conclusion

Recalibration and validation of the Charlson Comorbidity Index in acute kidney injury patients underwent continuous renal replacement therapy

Background

Comorbid conditions impact the survival of patients with severe acute kidney injury (AKI) who require continuous renal replacement therapy (CRRT). The weights assigned to comorbidities in predicting survival vary based on type of index, disease, and advances in management of comorbidities. We developed a modified Charlson Comorbidity Index (CCI) for use in patients with AKI requiring CRRT (mCCI-CRRT) and improved the accuracy of risk stratification for mortality.

Methods

A total of 828 patients who received CRRT between 2008 and 2013, from three university hospital cohorts was included to develop the comorbidity score. The weights of the comorbidities were recalibrated using a Cox proportional hazards model adjusted for demographic and clinical information. The modified index was validated in a university hospital cohort (n = 919) using the data of patients treated from 2009 to 2015.

Results

Weights for dementia, peptic ulcer disease, any tumor, and metastatic solid tumor were used to recalibrate the mCCI-CRRT. Use of these calibrated weights achieved a 35.4% (95% confidence interval [CI], 22.1%–48.1%) higher performance than unadjusted CCI in reclassification based on continuous net reclassification improvement in logistic regression adjusted for age and sex. After additionally adjusting for hemoglobin and albumin, consistent results were found in risk reclassification, which improved by 35.9% (95% CI, 23.3%–48.5%).

Conclusion

The mCCI-CRRT stratifies risk of mortality in AKI patients who require CRRT more accurately than does the original CCI, suggesting that it could serve as a preferred index for use in clinical practice.

Recalibration and validation of the Charlson Comorbidity Index in an Asian population: the National Health Insurance Service-National Sample Cohort study

Weights assigned to comorbidities in predicting mortality may vary based on the type of index disease and advances in the management of comorbidities. We aimed to develop a modified version of the Charlson Comorbidity Index (CCI) using an Asian nationwide database (mCCI-A), enabling the precise prediction of mortality rates in this population. The main data source used in this study was the National Health Insurance Service-National Sample Cohort (NHIS-NSC) obtained from the National Health Insurance database, which includes health insurance claims filed between January 1, 2002, and December 31, 2013, in Korea. Of the 1,025,340 individuals included in the NHIS-NSC, 570,716 patients who were hospitalized at least once were analyzed in this study. In total, 399,502 patients, accounting for 70% of the cohort, were assigned to the development cohort, and the remaining patients (n = 171,214) were assigned to the validation cohort. The mCCI-A scores were calculated by summing the weights assigned to individual comorbidities according to their relative prognostic significance determined by a multivariate Cox proportional hazard model. The modified index was validated in the same cohort. The Cox proportional hazard model provided reassigned severity weights for 17 comorbidities that significantly predicted mortality. Both the CCI and mCCI-A were correlated with mortality. However, compared with the CCI, the mCCI-A showed modest but significant increases in the c statistics. According to the analyses using continuous net reclassification improvement, the mCCI-A improved the net mortality risk reclassification by 44.0% (95% confidence intervals (CI), 41.6–46.5; p < 0.001). The mCCI-A facilitates better risk stratification of mortality rates in Korean inpatients than the CCI, suggesting that the mCCI-A may be a preferable index for use in clinical practice and statistical analyses in epidemiological studies.

Characterizing Comorbidity in Dialysis Patients: Principles of Measurement and Applications in Risk Adjustment and Patient Care

Comorbid conditions are highly prevalent in dialysis patients and are significant predictors of mortality and other adverse outcomes. Accordingly, it is important to account for differences in comorbid illness burden among groups of dialysis patients being compared. At present, there is no consensus on what conditions matter, how each should be defined, and what weights each carries when defining an individual's risk or case-mix severity. A number of comorbidity instruments, generic or disease specific, have been employed in dialysis populations. They differ by the representation and definition of conditions as well as instrument scoring. No instrument has been found to be superior to another in terms of predictive accuracy for mortality, and accuracy across the board is low. Further studies are needed to determine whether improvements would be found with the use of more specifically defined items and through assignment of item weights based on relationships for outcomes specifically in a dialysis population. The roles of other factors in risk prediction, such as markers of nutritional status, inflammation, or other physiological parameters, relative to comorbid conditions also need to be defined. Outcomes other than mortality are likely to identify different factors and/or different relationships than those noted for mortality, which also require study.

Comorbidity is important for risk adjusting comparative analyses in nonrandomized trials and quality of care assessments and may, in future, influence payment for dialysis services. Efforts to improve the management of comorbid illnesses are needed. Comorbid conditions must be documented accurately and uniformly in all dialysis patients to enable these applications.

Comparison of the Charlson Comorbidity Index and the Davies Score as a Predictor of Outcomes in PD Patients

Background

Comorbidity is a strong predictor and confounds many studies of outcomes. Previous studies have shown that the Charlson Comorbidity Index (CCI) and the Davies score predict mortality in peritoneal dialysis (PD) patients. However, there are few data on the comparison of comorbidity scores.

Objective

To compare the CCI (combines comorbidity and age) and Davies score (comorbidity score without age) to see if one score was superior to the other in predicting outcomes.

Design

Prospective database study.

Setting

Seven dialysis centers in Western Pennsylvania.

Participants

415 incident PD patients, starting PD from 1/1/90 to 2/1/00.

Measurements

The CCI and Davies score calculated at the start of PD; serum albumin levels and demographics at the start of PD; total hospitalizations and mortality, collected prospectively.

Results

The correlation between CCI and Davies was 0.80, p < 0.0001. The CCI was inversely correlated with serum albumin (–0.31, p < 0.0001). Davies was significantly correlated with age (0.32, p < 0.0001) and inversely correlated with albumin (–0.27, p < 0.0001). The CCI alone was a stronger predictor than Davies alone (score by best subsets regression 49.6 vs 42.0, p = 0.0058). The CCI and Davies with age appeared to be equivalent models of survival (49.61 vs 49.64). The best predictive models were CCI and initial albumin, or Davies, age, and initial albumin. Both CCI and Davies were predictors of hospitalization rates, but the model with the Davies score was better (Akaike information criterion 799.2 vs 850.2). The best predictive model was Davies, albumin, age, and race.

Conclusions

Both comorbidity scores were significant predictors of outcomes, with CCI the stronger predictor for mortality, but the Davies was a stronger predictor of hospitalizations. One or both should be done at the start of dialysis to predict outcome.

Markers of mineral metabolism and vascular access complications: The Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study

INTRODUCTION

Vascular access dysfunction is a major cause of morbidity in patients with end-stage renal disease (ESRD) on chronic hemodialysis. The effects of abnormalities in mineral metabolism on vascular access are unclear. In this study, we evaluated the association of mineral metabolites, including 25-hydroxy vitamin D (25(OH)D) and fibroblast growth factor-23 (FGF-23), with vascular access complications.

METHODS

We included participants from the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study who were using an arteriovenous fistula (AVF; n = 103) or arteriovenous graft (AVG; n = 116). Serum levels of 25(OH)D, FGF-23, parathyroid hormone (PTH), calcium, phosphorus, C-reactive protein (CRP) and interleukin-6 (IL-6) were assessed from stored samples. Participants were followed for up to 1 year or until a vascular access intervention or replacement.

FINDINGS

A total of 24 participants using an AVF and 43 participants using an AVG experienced access intervention. Those with 25(OH)D level in the lowest tertile (<11 ng/mL) had an increased risk of AVF intervention compared to those with higher 25(OH)D levels (adjusted relative hazard [aHR] = 3.28; 95% confidence interval [CI]: 1.31, 8.20). The highest tertile of FGF-23 (>3750 RU/mL) was associated with greater risk of AVF intervention (aHR = 2.56; 95% CI: 1.06, 6.18). Higher PTH was associated with higher risk of AVF intervention (aHR = 1.64 per SD of log(PTH); 95% CI: 1.02, 2.62). These associations were not observed in participants using an AVG. None of the other analytes were significantly associated with AVF or AVG intervention.

DISCUSSION

Low levels of 25(OH)D and high levels of FGF-23 and PTH are associated with increased risk of AVF intervention. Abnormalities in mineral metabolism are risk factors for vascular access dysfunction and potential therapeutic targets to improve outcomes.

Medical Record Documentation of Goals-of-Care Discussions Among Older Veterans With Incident Kidney Failure

RATIONALE & OBJECTIVE

Elicitation and documentation of patient preferences is at the core of shared decision making and is particularly important among patients with high anticipated mortality. The extent to which older patients with incident kidney failure undertake such discussions with their providers is unknown and its characterization was the focus of this study.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A random sample of veterans 67 years and older with incident kidney failure receiving care from the US Veterans Health Administration between 2005 and 2010.

EXPOSURES

Demographic and facility characteristics, as well as predicted 6-month mortality risk after dialysis initiation and documentation of resuscitation preferences.

OUTCOMES

Documented discussions of dialysis treatment and supportive care.

ANALYTICAL APPROACH

We reviewed medical records over the 2 years before incident kidney failure and up to 1 year afterward to ascertain the frequency and timing of documented discussions about dialysis treatment, supportive care, and resuscitation. Logistic regression was used to identify factors associated with these documented discussions.

RESULTS

The cohort of 821 veterans had a mean age of 80.9±7.2 years, and 37.2% had a predicted 6-month mortality risk>20% with dialysis. Documented discussions addressing dialysis treatment and resuscitation were present in 55.6% and 77.1% of patients, respectively. Those addressing supportive care were present in 32.4%. The frequency of documentation varied by mortality risk and whether the patient ultimately started dialysis. In adjusted analyses, the frequency and pattern of documentation were more strongly associated with geographic location and receipt of outpatient nephrology care than with patient demographic or clinical characteristics.

LIMITATIONS

Documentation may not fully reflect the quality and content of discussions, and generalizability to nonveteran patients is limited.

CONCLUSIONS

Among older veterans with incident kidney failure, discussions of dialysis treatment are decoupled from other aspects of advance care planning and are suboptimally documented, even among patients at high risk for mortality.

Comorbidities Can Predict Mortality of Kidney Transplant Recipients: Comparison With the Charlson Comorbidity Index. Transplant Proc. 2018;50:1068-1073. [PMID: 29731067 DOI: 10.1016/j.transproceed.2018.01.044]

BACKGROUND

Comorbid conditions are important in the survival of kidney transplant recipients. The weights assigned to comorbidities to predict survival may vary based on the type of index disease and advances in the management of comorbidities. We aimed to develop a modified Charlson comorbidity index (CCI) in renal allograft recipients (mCCI-KT), thereby improving risk stratification for mortality.

METHODS

A total of 3765 recipients in a multicenter cohort were included to develop a comorbidity score. The weights of the comorbidities, per the CCI, were recalibrated using a Cox proportional hazards model.

RESULTS

Peripheral vascular disease, liver disease, myocardial infarction, and diabetes in the CCI were selected from the Cox proportional hazards model. Thus, the mCCI-KT included 4 comorbidities with recalibrated severity weights. Whereas the CCI did not discriminate for survival, the mCCI-KT provided significant discrimination for survival using the Kaplan-Meier method and Cox regression analysis. The mCCI-KT showed modest increases in c-statistics (0.54 vs 0.52, P = .001) and improved net mortality risk reclassification by 16.3% (95% confidence interval, 3.2-29.4; P = .015) relative to the CCI.

CONCLUSION

The mCCI-KT stratifies the risk for mortality in renal allograft recipients better than the CCI, suggesting that it may be a preferred index for use in clinical practice.

The Factors Affecting Survival in Geriatric Hemodialysis Patients

Introduction

The number of geriatric patients is increasing in hemodialysis population over the years and mortality is higher in this group of patients. This study evaluated the factors affecting geriatric hemodialysis patient survival.

Materials and Methods

This retrospective cohort study enrolled patients discharged from our nephrology clinic from 2009 to 2014. Data collected included demographics, Eastern Cooperative Oncology Group-Performance Status, vascular access type, and metabolic parameters. Comorbidity was quantified using the modified Liu comorbidity index. The outcome measure was mortality.

Results

The study enrolled 99 elderly dialysis patients (42.4% women (n = 42); mean age 75 ± 7 years). The mean follow-up duration was 19.7 ± 11 months. The mortality rate over the four years was 47.5% (n = 46). The modified Liu comorbidity index score, patient age, and Eastern Cooperative Oncology Group-Performance Status were significantly related to mortality in univariate and multivariate analyses.

Conclusion

The present study revealed that comorbidities and low performance status at the onset of dialysis had shortened the survival time in the geriatric hemodialysis patient group.

Influence of Co-Morbidity on Health-Related Quality of Life in Patients Treated with Hemodialysis

Studies on the outcome of hemodialysis (HD) patients over time have mainly focused on morbidity and mortality, but currently, the importance of measuring the patient's health-related quality of life (HRQoL) is being increasingly recognized. On the other hand, comorbidity is the single most important determinant of outcome in patients on HD. The aims of this study were to evaluate HRQoL in patients at the initiation of HD therapy (incident cohort), and in patients on long-term HD treatment (prevalent cohort), and to establish the relationship between the presence of comorbidity and patient's HRQoL. The study enrolled 229 patients on HD, divided into two groups: prevalent cohort comprised 192 patients on chronic HD more than 3 months, and incident cohort with 37 patients who started their dialysis during the study. Comorbidity was assessed using the Index of Coexistent Diseases (ICED), including two sub-indexes: Index of Disease Severity (IDS), a medical record review of 16 medical conditions, and Index of Physical Impairment (IPI), an observer-based assessment of 11 physical functions. ICED scores range from 0 to 3, with higher levels reflecting more severe comorbidity. Patient's self-assessment of HRQoL was measured by the 36-item Short Form Health Survey Questionnaire (SF-36), encompassing 8 summary scales and 2 summary dimensions. Based on the ICED index level, in both groups of patients (prevalent and incident group), a high presence of associated diseases was observed, i.e. 56.8 % and 67.6 % respectively. Indicators of comorbidities have negative and statistically significant correlation, so that any increase of IDS and IPI indexes produces significant decrease of HRQoL parameters. HRQoL summary scales in both groups of patients were similar, but generally with lower values in incident subjects and with statistical significance only in social functioning (SF) scale (40.5 ± 24.9 vs 51.0 ± 27.2). In the incident group of patients, one year of HD treatment was associated with a slight improvement in all HRQoL parameters, but statistical significance (p < 0.05) was observed only in the role-physical limitation (RP) scale and SF scale.

Conclusions

In the patients on HD treatment, comorbid conditions have negative and statistically significant correlation with parameters of HRQoL, and could explain poor HRQoL to a remarkable extent. One year after starting HD, patients reported better scores in some domains, especially in the RP and SF scale. From a clinical perspective, parameters of HRQoL and comorbidities should be considered in the follow up of patients treated with HD. (Int J Artif Organs 2006; 29: 1053–61)

Free and total p-cresol sulfate levels and infectious hospitalizations in hemodialysis patients in CHOICE and HEMO

The uremic syndrome is attributed to progressive retention of compounds that, under normal conditions, are excreted by the healthy kidneys. p-cresol sulfate (PCS), a prototype protein-bound uremic retention solute, has been shown to exert toxic effects in vitro. Recent studies have identified relations between increased levels of PCS and indoxyl sulfate (IS) and adverse clinical outcomes in hemodialysis patients. We explored the relationship between free and total PCS and IS with infection-related hospitalizations (IH) and septicemia in 2 cohorts, Choices for Healthy Outcomes in Caring for end-stage renal disease (ESRD) Study (CHOICE) and Hemodialysis Study (HEMO).We measured free and total levels of PCS and IS in stored specimens in CHOICE, a cohort of 464 incident hemodialysis patients enrolled in 1995 to 1998 and followed for an average of 3.4 years and in a prevalent dialysis cohort of 495 patients enrolled in HEMO from 1995 to 2000 and followed for an average of 4.4 years. We measured free PCS and IS using mass spectroscopy. The 2 cohorts were linked to United States Renal Data System (USRDS) Medicare billing records to ascertain IH over follow-up. We examined the association of free and total levels of PCS and IS with IH and septicemia using multilevel Poisson regression models adjusted for demographics, comorbidities, clinical factors, and laboratory tests including residual kidney function. We stratified patients a priori based on gastrointestinal (GI) disease as PCS and IS are produced in colon.In CHOICE, highest tertile of free PCS in multivariable model was associated with 50% higher risk of IH [95% CI = 1.01-2.23] compared with lowest tertile in patients with no-GI disease. A significant trend was noted between greater levels of free PCS and septicemia in no-GI disease group in both cohorts, while no association was noted in GI disease group. Total PCS concentrations were not associated with either IH or septicemia in either cohort. No significant risk of IH or septicemia was noted with higher levels of free or total IS in either GI or no-GI disease group.These results suggest an association between higher concentrations of free PCS and infection-related and sepsis-related hospitalizations in hemodialysis patients. Better methods of dialysis should be developed to evaluate the utility of removing PCS and its effect on the outcome and also therapies to decrease gastrointestinal tract production of uremic solutes.

Development and Validation of the Modified Charlson Comorbidity Index in Incident Peritoneal Dialysis Patients: A National Population-Based Approach

Background

The utility of applying the Charlson comorbidity index (CCI) to peritoneal dialysis (PD) patients is disputed because the relative weight of each comorbidity in PD patients may be different from those in other chronic diseases. We aimed to develop and validate a modified CCI in incident PD patients (mCCI-IPD) for better risk stratification and prediction of mortality.

Methods

The mCCI-IPD was developed using data from all Korean adult incident PD patients between 2005 and 2008 ( n = 7,606). Multivariate Cox regression was used to determine new weights for the individual comorbidities in the CCI. The prognostic performance of the mCCI-IPD was validated in an independent cohort ( n = 664) through c-statistics and continuous net reclassification improvement (cNRI).

Results

A total of 75.5% of the patients in the development cohort had 1 or more comorbidities. The Cox proportional hazards model provided reassigned severity weights for the 11 comorbidities that significantly predicted mortality. In the validation cohort, the CCI and mCCI-IPD scores were both correlated with survival and showed no differences in their c-statistics. However, multivariate analyses using cNRI revealed that the mCCI-IPD provided a 38.2% improvement in mortality risk assessment compared with the CCI (95% confidence interval [CI], 15.3 – 61.0; p < 0.001). These significant reclassification improvements were observed consistently in subjects with events (cNRIEvent, 28.2% [95% CI, 6.9 – 49.5; p = 0.009]) and without events (cNRINon-event, 10.0% [95% CI, 1.7 – 18.2; p = 0.019]).

Conclusions

Compared with the CCI, the mCCI-IPD showed better performance in mortality prediction for incident PD patients. Therefore, this tool may be used as a preferred index for statistical analysis and clinical decision-making.

Race, Mineral Homeostasis and Mortality in Patients with End-Stage Renal Disease on Dialysis

BACKGROUND

Abnormalities in mineral homeostasis are ubiquitous in patients on dialysis, and influenced by race. In this study, we determine the race-specific relationship between mineral parameters and mortality in patients initiating hemodialysis.

METHODS

We measured the levels of fibroblast growth factor 23 (FGF23) and 25-hydroxyvitamin D (25 D) in 184 African American and 327 non-African American hemodialysis patients who enrolled between 1995 and 1998 in the Choices for Healthy Outcomes in Caring for ESRD Study. Serum calcium, phosphorus, parathyroid hormone (PTH) and total alkaline phosphatase levels were averaged from clinical measurements during the first 4.5 months of dialysis. We evaluated the associated prospective risk of mortality using multivariable Cox proportional hazards models stratified by race.

RESULTS

PTH and total alkaline phosphatase levels were higher, whereas calcium, phosphorus, FGF23 and 25 D levels were lower in African Americans compared to those of non-African Americans. Higher serum phosphorus and FGF23 levels were associated with greater mortality risk overall; however, phosphorus was only associated with risk among African Americans (HR 5.38, 95% CI 2.14-13.55 for quartile 4 vs. 1), but not among non-African Americans (p-interaction = 0.04). FGF23 was associated with mortality in both groups, but more strongly in African Americans (HR 3.91, 95% CI 1.74-8.82 for quartiles 4 vs. 1; p-interaction = 0.09). Serum calcium, PTH, and 25 D levels were not consistently associated with mortality. The lowest and highest quartiles of total alkaline phosphatase were associated with higher mortality risk, but this did not differ by race (p-interaction = 0.97).

CONCLUSIONS

Aberrant phosphorus homeostasis, reflected by higher phosphorus and FGF23, may be a risk factor for mortality in patients initiating hemodialysis, particularly among African Americans.

Importance of simultaneous evaluation of multiple risk factors for hemodialysis patients' mortality and development of a novel index: dialysis outcomes and practice patterns study

BACKGROUND

For hemodialysis (HD) patients, many risk factors for death are associated with each other intricately. However, they are often considered separately in clinical settings. We evaluated the maintenance HD patients' risk of death within one year from multiple risk factors simultaneously considering their interrelationships using a novel index (survival index, SI) for HD patients in the United States developed using data from the Dialysis Outcomes and Practice Patterns Study (DOPPS).

METHODS

We analyzed data from 3899 and 3765 patients to develop and validate SI, respectively. To predict death within one year, candidate models were developed using logistic regression models. The final model was determined by comparing the accuracy among the models for the prediction of deaths.

RESULTS

The model included age; body mass index; serum creatinine, albumin, total cholesterol and phosphorus levels; history of cardiovascular diseases; and arteriovenous fistula use. SI showed a higher accuracy in predicting death (c-statistic, 0.739) than geriatric nutritional risk index (0.647) and serum albumin level (0.637). The probability of death predicted on the basis of SI matched the observed number of deaths. Cox proportional hazard models for time-dependent SI showed that patients with low SI had a higher risk of death than patients with high SI [reference, Group 4 (26.1≤SI)]; Group 1 (SI<12.7), adjusted hazard ratio, 7.97 (95% CI, 5.02, 12.65); Group 2 (12.7≤SI<19.0), 3.18 (95% CI, 1.96, 5.16); Group 3 (19.0≤SI<26.1), 2.20 (95% CI, 1.33, 3.66).

CONCLUSION

Results of this study suggest that the simultaneous evaluation of multiple risk factors can more accurately assess patients' prognosis and identify patients at an increased risk of death than single factors.

Recalibration and validation of the Charlson comorbidity index in Korean incident hemodialysis patients

BACKGROUND

Weights assigned to comorbidities to predict mortality may vary based on the type of index disease and advances in the management of comorbidities. We aimed to develop a modified Charlson comorbidity index (CCI) in incident hemodialysis patients (mCCI-IHD), thereby improving risk stratification for mortality.

METHODS

Data on 24,738 Koreans who received their first hemodialysis treatment between 2005 and 2008 were obtained from the Korean Health Insurance dataset. The mCCI-IHD score were calculated by summing up the weights which were assigned to individual comorbidities according to their relative prognostic significance determined by multivariate Cox proportional hazards model. The modified index was validated in an independent nationwide prospective cohort (n=1,100).

RESULTS

The Cox proportional hazards model revealed that all comorbidities in the CCI except ulcers significantly predicted mortality. Thus, the mCCI-IHD included 14 comorbidities with re-assigned severity weights. In the validation cohort, both the CCI and the mCCI-IHD were correlated with mortality. However, the mCCI-IHD showed modest but significant increases in c statistics compared with the CCI at 6 months and 1 year. The analyses using continuous net reclassification improvement revealed that the mCCI-IHD improved net mortality risk reclassification by 24.6% (95% CI, 2.5-46.7; P=0.03), 26.2% (95% CI, 1.0-51.4; P=0.04) and 42.8% (95% CI, 4.9-80.8; P=0.03) with respect to the CCI at 6 months and 1 and 2 years, respectively.

CONCLUSIONS

The mCCI-IHD facilitates better risk stratification for mortality in incident hemodialysis patients compared with the CCI, suggesting that it may be a preferred index for use in clinical practice and the statistical analysis of epidemiological studies.

Free Levels of Selected Organic Solutes and Cardiovascular Morbidity and Mortality in Hemodialysis Patients: Results from the Retained Organic Solutes and Clinical Outcomes (ROSCO) Investigators

Background and Objectives

Numerous substances accumulate in the body in uremia but those contributing to cardiovascular morbidity and mortality in dialysis patients are still undefined. We examined the association of baseline free levels of four organic solutes that are secreted in the native kidney — p-cresol sulfate, indoxyl sulfate, hippurate and phenylacetylglutamine — with outcomes in hemodialysis patients.

Design, Setting, Participants and Measurements

We measured these solutes in stored specimens from 394 participants of a US national prospective cohort study of incident dialysis patients. We examined the relation of each solute and a combined solute index to cardiovascular mortality and morbidity (first cardiovascular event) using Cox proportional hazards regression adjusted for demographics, comorbidities, clinical factors and laboratory tests including Kt/V_UREA.

Results

Mean age of the patients was 57 years, 65% were white and 55% were male. In fully adjusted models, a higher p-cresol sulfate level was associated with a greater risk (HR per SD increase; 95% CI) of cardiovascular mortality (1.62; 1.17–2.25; p=0.004) and first cardiovascular event (1.60; 1.23–2.08; p<0.001). A higher phenylacetylglutamine level was associated with a greater risk of first cardiovascular event (1.37; 1.18–1.58; p<0.001). Patients in the highest quintile of the combined solute index had a 96% greater risk of cardiovascular mortality (1.96; 1.05–3.68; p=0.04) and 62% greater risk of first cardiovascular event (1.62; 1.12–2.35; p=0.01) compared with patients in the lowest quintile. Results were robust in sensitivity analyses.

Conclusions

Free levels of uremic solutes that are secreted by the native kidney are associated with a higher risk of cardiovascular morbidity and mortality in incident hemodialysis patients.

Focused risk analysis: regression model based on 5,314 total hip and knee arthroplasty patients from a single institution

We aimed to identify significant demographic, preoperative comorbidity and surgical predictors for major complications for use in the development of a risk prediction tool for a well-defined population as Total Joint Arthroplasty (TJA) patients. Data on 5314 consecutive patients who underwent primary total hip or knee arthroplasty from October 1, 2008 through September 30, 2011 at a single institution were used in a multivariate regression analysis. The overall incidence of a primary endpoint (reoperation during same admission, extended length of stay, and 30-day readmission) was 3.8%. Significant predictors include certain preexisting genitourinary, circulatory and respiratory conditions; ASA>2; advanced age and prolonged operating time. Mental health conditions demonstrate a strong predictive effect for subsequent serious complication(s) in TJA patients and should be included in a risk-adjustment tool.

Vascular access type, inflammatory markers, and mortality in incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study

BACKGROUND

Few reports have shown an association between access type and inflammatory marker levels in a longitudinal cohort. We investigated the role of access type on serial levels of inflammatory markers and the role of inflammatory markers in mediating the association of access type and risk of mortality in a prospective study of incident dialysis patients.

STUDY DESIGN

Cohort study, post hoc analysis of the CHOICE (Choices for Healthy Outcomes in Caring for ESRD) Study.

SETTING & PARTICIPANTS

In 583 participants, inflammation was assessed by measuring serum C-reactive protein (CRP) and interleukin 6 (IL-6) after access placement and at multiple times during 3 years' follow-up. Type of access was categorized as central venous catheter (CVC), arteriovenous graft (AVG), and arteriovenous fistula (AVF), and changes over time were recorded.

PREDICTOR

Access type, age, sex, race, body mass index, diabetes, cardiovascular disease, and serum albumin level.

OUTCOMES

CRP level, IL-6 level, and mortality.

MEASUREMENTS

We used mixed-effects pattern mixture models to study the association between access type and repeated measurements of inflammation and survival analysis to investigate the association of access type and mortality, adjusting for predictors.

RESULTS

In a mixed-effects pattern mixture model, compared with AVFs, the presence of CVCs and AVGs was associated with 62% (P=0.02) and 30% (P=0.05) increases in average CRP levels, respectively. A Cox proportional hazards model yielded nonsignificant associations of CVC and AVG use (vs AVFs) with risk of mortality when adjusted for inflammatory marker levels. Higher CRP levels were associated with increased risk of CVC failure than lower CRP levels.

LIMITATIONS

CRP and IL-6 measurements not performed for all hemodialysis patients.

CONCLUSIONS

CVCs, compared with AVFs, are associated with a greater state of inflammation in incident hemodialysis patients, and the association of catheter use and mortality may be mediated by access-induced inflammation. Our findings support recommendations for the early removal or avoidance of CVC placements.

Troponin I and NT-proBNP and the association of systolic blood pressure with outcomes in incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study

BACKGROUND

There is uncertainty regarding treatment of hypertension in hemodialysis patients due to the observed J-shaped association between blood pressure (BP) and death. We hypothesized that this association reflects confounding by cardiovascular disease (CVD) and that stratification by CVD biomarkers, cardiac troponin I (cTnI) and N-terminal fragment of prohormone brain natriuretic peptide (NT-proBNP), might change this association.

STUDY DESIGN

National prospective cohort study.

SETTING & PARTICIPANTS

446 incident hemodialysis patients.

PREDICTOR

Predialysis systolic BP.

OUTCOMES

Mortality (all-cause and CVD) and first CVD event assessed using Cox regression adjusted for demographics, comorbid conditions, and clinical factors.

MEASUREMENTS

Participants with cTnI level ≥0.1 ng/mL or NT-proBNP level ≥9,252 pg/mL were classified as the high-biomarker group; remaining participants were included in the low-biomarker group.

RESULTS

Participants in the high-biomarker group (n=138 [31%]) were older (61 vs. 57 years) and had a higher prevalence of CVD (67% vs. 23%), but similar baseline BPs (152 vs. 153 mm Hg). There were 323 deaths (143 from CVD) and 271 CVD events. The high-biomarker group had a higher risk of mortality than the low-biomarker group (HR, 1.75; 95% CI, 1.37-2.24). The association between BP and outcomes differed between the 2 biomarker groups (P for interaction=0.01, 0.2, and 0.07 for all-cause mortality, CVD mortality, and first CVD event, respectively). In the low-biomarker group, BP was associated with greater risk of outcomes: HR per 10 mm Hg higher BP was 1.07 (95% CI, 1.01-1.14), 1.10 (95% CI, 0.96-1.25), and 1.04 (95% CI, 0.96-1.13) for all-cause mortality, CVD mortality, and first CVD event, respectively. Importantly, lower BP was not associated with increased risk of outcomes in stratified models, including for those in high biomarker group.

LIMITATIONS

BP measurements not standardized.

CONCLUSIONS

The observed J-shaped association between BP and outcomes in hemodialysis patients is due to confounding by subclinical CVD. A stratification approach based on cTnI and NT-proBNP levels has the potential to inform BP treatment in hemodialysis patients.

High cost and low survival rate in high comorbidity incident elderly hemodialysis patients

BACKGROUND

The comorbidity index is a predictor of mortality in dialysis patients but there are few reports for predicting elderly dialysis mortality and national population-based cost studies on elderly dialysis. The aim of this study was to evaluate the long-term mortality of incident elderly dialysis patients using the Deyo-Charlson comorbidity index (CCI) and to assess the inpatient and outpatient visits along with non-dialysis costs.

METHODS

Data were obtained from catastrophic illness registration of the Taiwan National Health Insurance Research Database. Incident elderly dialysis patients (age ≥75 years) receiving hemodialysis for more than 90 days between Jan 1, 1998, and Dec 31, 2007, were included. Baseline comorbidities were determined one year prior to the first dialysis day according to ICD-9 CM codes. Survival time, mortality rate, hospitalization time, outpatient visit frequency, and costs were calculated for different age and CCI groups.

RESULTS

In 10,759 incident elderly hemodialysis patients, hazard ratios for all-cause mortality were significantly increased in the different age groups (p < 0.001) and CCI patients (p < 0.001). Death rates increased with both increasing age and CCI score. High comorbidity incident hemodialysis and elderly patients were found to have increased length of hospital stay and total hospitalization costs.

CONCLUSIONS

This population-based cohort study indicated that both age and higher CCI values were predictors of survival in incident elderly hemodialysis. Increased costs and mortality rates were evident in the oldest patients and in those with high CCI scores. Conservative treatment might be considered in high comorbidity and low-survival rate end stage renal disease (ESRD) patients.

The new comorbidity index for predicting survival in elderly dialysis patients: a long-term population-based study

Background

The worldwide elderly (≥65 years old) dialysis population has grown significantly. This population is expected to have more comorbid conditions and shorter life expectancies than the general elderly population. Predicting outcomes for this population is important for decision-making. Recently, a new comorbidity index (nCI) with good predictive value for patient outcomes was developed and validated in chronic dialysis patients regardless of age. Our study examined the nCI outcome predictability in elderly dialysis patients.

Methods and Findings

For this population-based cohort study, we used Taiwan's National Health Insurance Research Database of enrolled elderly patients, who began maintenance dialysis between January 1999 and December 2005. A total of 21,043 incident dialysis patients were divided into 4 groups by nCI score (intervals ≤3, 4–6, 7–9, ≥10) and followed nearly for 10 years. All-cause mortality and life expectancy were analyzed. During the follow-up period, 11272 (53.55%) patients died. Kaplan-Meier curves showed significant group difference in survival (log-rank: P<0.001). After stratification by age, life expectancy was found to be significantly longer in groups with lower nCI scores.

Conclusion

The nCI, even without the age component, is a strong predictor of mortality in elderly dialysis patients. Because patients with lower nCI scores may predict better survival, more attention should paid to adequate dialysis rather than palliative care, especially in those without obvious functional impairments.

The elderly patient on dialysis: geriatric considerations

The burgeoning population of older dialysis patients presents opportunities to provide personalized care. The older dialysis population has a high burden of chronic health conditions, decrements in quality of life and a high risk of death. In order to address these challenges, this review will recommend routinely establishing prognosis through the use of prediction instruments and communicating these findings to older patients. The challenges to prognosis in adults with end-stage renal disease (ESRD) include the subjective nature of clinical judgment, application of appropriate prognostic tools and communication of findings to patients and caregivers. There are three reasons why we believe these conversations occur infrequently with the dialysis population. First, there have previously been no clinically practical instruments to identify individuals undergoing maintenance hemodialysis (HD) who are at highest risk for death. Second, nephrologists have not been trained to have conversations about prognosis and end-of-life care. Third, other than hospitalizations and accrual of new diagnoses, there are no natural milestone guidelines in place for patients supported by dialysis. The prognosis can be used in shared decision-making to establish goals of care, limits on dialysis support or parameters for withdrawal from dialysis. As older adults with ESRD benefit from kidney transplantation, prognosis can also be used to determine who should be referred for evaluation by a kidney transplant team. The use of prognosis in older adults may determine approaches to optimize well-being and personalize care among older adults ranging from hospice to kidney transplantation.

Serum fructosamine and glycated albumin and risk of mortality and clinical outcomes in hemodialysis patients

OBJECTIVE

Assays for serum total glycated proteins (fructosamine) and the more specific glycated albumin may be useful indicators of hyperglycemia in dialysis patients, either as substitutes or adjuncts to standard markers such as hemoglobin A1c, as they are not affected by erythrocyte turnover. However, their relationship with long-term outcomes in dialysis patients is not well described.

RESEARCH DESIGN AND METHODS

We measured fructosamine and glycated albumin in baseline samples from 503 incident hemodialysis participants of a national prospective cohort study, with enrollment from 1995-1998 and median follow-up of 3.5 years. Outcomes were all-cause and cardiovascular disease (CVD) mortality and morbidity (first CVD event and first sepsis hospitalization) analyzed using Cox regression adjusted for demographic and clinical characteristics, and comorbidities.

RESULTS

Mean age was 58 years, 64% were white, 54% were male, and 57% had diabetes. There were 354 deaths (159 from CVD), 302 CVD events, and 118 sepsis hospitalizations over follow-up. Both fructosamine and glycated albumin were associated with all-cause mortality; adjusted HR per doubling of the biomarker was 1.96 (95% CI 1.38-2.79) for fructosamine and 1.40 (1.09-1.80) for glycated albumin. Both markers were also associated with CVD mortality [fructosamine 2.13 (1.28-3.54); glycated albumin 1.55 (1.09-2.21)]. Higher values of both markers were associated with trends toward a higher risk of hospitalization with sepsis [fructosamine 1.75 (1.01-3.02); glycated albumin 1.39 (0.94-2.06)].

CONCLUSIONS

Serum fructosamine and glycated albumin are risk factors for mortality and morbidity in hemodialysis patients.

Predicting mortality of incident dialysis patients in Taiwan--a longitudinal population-based study

Background

Comorbid conditions are highly prevalent among patients with end-stage renal disease (ESRD) and index score is a predictor of mortality in dialysis patients. The aim of this study is to perform a population-based cohort study to investigate the survival rate by age and Charlson comorbidity index (CCI) in incident dialysis patients.

Methods

Using the catastrophic illness registration of the Taiwan National Health Insurance Research Database for all patients from 1 January 1998 to 31 December 2008, individuals newly diagnosed with ESRD and receiving dialysis for more than 90 days were eligible for our study. Individuals younger than 18 years or renal transplantation patients either before or after dialysis were excluded. We calculated the CCI, age-weighted CCI by Deyo-Charlson method according to ICD-9 code and categorized CCI into six groups as index scores <3, 4–6, 7–9, 10–12, 13–15, >15. Cox regression models were used to analyze the association between age, CCI and survival, and the risk markers of survival.

Results

There were 79,645 incident dialysis patients, whose mean age (± SD) was 60.96 (±13.92) years; 51.43% of patients were women and 51.2% were diabetic. In cox proportional hazard models and stratifying by age, older patients had significantly higher mortality than younger patients. The mortality risk was higher in persons with higher CCI as compared with low CCI. Mortality increased steadily with higher age or comorbidity both for unadjusted and for adjusted models. For all age groups, mortality rates increased in different CCI groups with the highest rates occurring in the oldest age groups.

Conclusions

Age and CCI are both strong predictors of survival in Taiwan. The older age or higher comorbidity index in incident dialysis patient is associated with lower long-term survival rates. These population-based estimates may assist clinicians who make decisions when patients need long-term dialysis.

Association between oral nutritional supplementation and clinical outcomes among patients with ESRD

BACKGROUND AND OBJECTIVES

Oral nutritional supplementation (ONS) was provided to ESRD patients with hypoalbuminemia as part of Fresenius Medical Care Health Plan's (FMCHP) disease management. This study evaluated the association between FMCHP's ONS program and clinical outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Analyses included FMCHP patients with ONS indication (n=470) defined as 2-month mean albumin <3.8 g/dl until reaching a 3-month mean ≥3.8 g/dl from February 1, 2006 to December 31, 2008. Patients did not receive ONS if deemed inappropriate or refused. Patients on ONS were compared with patients who were not, despite meeting ONS indication. Patients with ONS indication regardless of use were compared with Medicare patients with similar serum albumin levels from the 2007 Centers for Medicare and Medicaid Services Clinical Performance Measures Project (CPM). Cox models calculated adjusted hospitalization and mortality risks at 1 year.

RESULTS

Among patients with indication for ONS, 276 received supplements and 194 did not. ONS use was associated with 0.058 g/dl higher serum albumin overall (P=0.02); this difference decreased by 0.001 g/dl each month (P=0.05) such that the difference was 0.052 g/dl (P=0.04) in month 6 and the difference was no longer significant in month 12 . In analyses based on ONS use, ONS patients had lower hospitalization at 1 year (68.4%; P<0.01) versus patients without ONS (88.7%), but there was no significant reduction in mortality risk (P=0.29). In analyses based on ONS indication, patients with indication had lower mortality at 1 year (16.2%) compared with CPM patients (23.4%; P<0.01).

CONCLUSIONS

These findings suggest that ONS use was associated with significantly lower hospitalization rates but had no significant effect on mortality in a disease management setting.

Serum β-trace protein and risk of mortality in incident hemodialysis patients

BACKGROUND AND OBJECTIVES

Residual kidney function in dialysis patients is associated with better survival, but there are no simple methods for its assessment. β-Trace protein is a novel endogenous filtration marker of kidney function that is not removed during hemodialysis and may serve as a marker for residual kidney function similar to serum creatinine in patients not on dialysis. The objective of this study was to determine the association of serum β-trace protein with mortality in incident hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Serum β-trace protein was measured in baseline samples from 503 participants of a national prospective cohort study of incident dialysis patients with enrollment during 1995-1998 and follow-up until 2004. Outcomes were all-cause and cardiovascular disease mortality analyzed using Cox regression adjusted for demographic, clinical, and treatment factors.

RESULTS

Serum β-trace protein levels were higher in individuals with no urine output compared with individuals with urine output (9.0±3.5 versus 7.6±3.1 mg/L; P<0.001). There were 321 deaths (159 deaths from cardiovascular disease) during follow-up (median=3.3 years). Higher β-trace protein levels were associated with higher risk of mortality. The adjusted hazard ratio and 95% confidence interval for all-cause mortality per doubling of serum β-trace protein was 1.36 (1.09-1.69). The adjusted hazard ratios (95% confidence intervals) for all-cause mortality in the middle and highest tertiles compared with the lowest tertile were 0.95 (0.69-1.32) and 1.72 (1.25-2.37). Similar results were noted for cardiovascular disease mortality.

CONCLUSIONS

The serum level of β-trace protein is an independent predictor of death and cardiovascular disease mortality in incident hemodialysis patients.

Proposal for a recovery prediction method for patients affected by acute mediastinitis

BACKGROUND

An attempt to find a prediction method of death risk in patients affected by acute mediastinitis. There is not such a tool described in available literature for that serious disease.

METHODS

The study comprised 44 consecutive cases of acute mediastinitis. General anamnesis and biochemical data were included. Factor analysis was used to extract the risk characteristic for the patients. The most valuable results were obtained for 8 parameters which were selected for further statistical analysis (all collected during few hours after admission). Three factors reached Eigenvalue >1. Clinical explanations of these combined statistical factors are: Factor1 - proteinic status (serum total protein, albumin, and hemoglobin level), Factor2 - inflammatory status (white blood cells, CRP, procalcitonin), and Factor3 - general risk (age, number of coexisting diseases). Threshold values of prediction factors were estimated by means of statistical analysis (factor analysis, Statgraphics Centurion XVI).

RESULTS

The final prediction result for the patients is constructed as simultaneous evaluation of all factor scores. High probability of death should be predicted if factor 1 value decreases with simultaneous increase of factors 2 and 3. The diagnostic power of the proposed method was revealed to be high [sensitivity =90%, specificity =64%], for Factor1 [SNC = 87%, SPC = 79%]; for Factor2 [SNC = 87%, SPC = 50%] and for Factor3 [SNC = 73%, SPC = 71%].

CONCLUSION

The proposed prediction method seems a useful emergency signal during acute mediastinitis control in affected patients.

Charlson comorbidity score is a strong predictor of mortality in hemodialysis patients

PURPOSE

The Charlson comorbidity index (CCI) is a commonly used scale for assessing morbidity, but its role in assessing mortality in hemodialysis patients is not clear. Age, a component of CCI, is a strong risk factor for morbidity and mortality in chronic diseases and correlates with comorbidities. We hypothesized that the Charlson comorbidity index without age is a strong predictor of mortality in hemodialysis patients.

METHODS

A 6-year cohort of 893 hemodialysis patients was examined for an association between a modified CCI (without age and kidney disease) (mCCI) and mortality.

RESULTS

Patients were 53±15 years old (mean±SD), had a median mCCI score of 2, and included 47% women, 31% African Americans and 55% diabetics. After adjusting for case-mix and nutritional and inflammatory markers including C-reactive protein and interleukin-6, 2nd (mCCI: 1-2), 3rd (mCCI=3), and 4th (mCCI: 4-9) quartiles compared to 1st (mCCI=0) quartiles showed death hazard ratios (95% confidence intervals) of 1.43 (0.92-2.23), 1.70 (1.06-2.72), and 2.33 (1.43-3.78), respectively. The mCCI-death association was robust in non-African Americans. The CCI-death association linearity was verified in cubic splines. Each 1 unit higher mCCI score was associated with a death hazard ratio of 1.16 (1.07-1.27).

CONCLUSIONS

CCI independent of age is a robust and linear predictor of mortality in hemodialysis patients, in particular in non-African Americans.

Predictors of sudden cardiac death: a competing risk approach in the hemodialysis study

BACKGROUND AND OBJECTIVES

There are few data on risk factors for sudden cardiac death (SCD) in patients undergoing hemodialysis (HD). The study objective was to identify predictors associated with various causes of death in the Hemodialysis (HEMO) Study and to develop a prediction model for SCD using a competing risk approach.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this analysis of 1745 HEMO participants, all-cause mortality was classified as SCD, non-SCD, and noncardiac death. Predictors for each cause of death were evaluated using cause-specific Cox proportional hazards models, and a competing risk approach was used to calculate absolute risk predictions for SCD.

RESULTS

During a median follow-up of 2.5 years, 808 patients died. Rates of SCD, non-SCD, and noncardiac death were 22%, 17%, and 61%, respectively. Predictors of various causes of death differ somewhat in HD patients. Age, diabetes, peripheral vascular disease, ischemic heart disease, serum creatinine, and alkaline phosphatase were independent predictors of SCD. The 3-year C-statistic for SCD was 0.75 (95% confidence interval, 0.70-0.79), and calibration was good (χ(2)=1.1; P=0.89). At years 3 and 5 of follow-up, the standard Cox model overestimated the risk for SCD as compared with the competing risk approach on the relative scale by 25% and 46%, respectively, and on the absolute scale by 2% and 6%, respectively.

CONCLUSIONS

Predictors of various causes of death differ in HD patients. The proposed prediction model for SCD accounts for competing causes of death. External validation of this model is required.

Heart failure severity scoring system and medical- and health-related quality-of-life outcomes: the HEMO study

BACKGROUND

Cardiac disease is the leading cause of death in US prevalent hemodialysis (HD) patients. There is a lack of data about the impact of the severity of heart failure (HF) on outcomes and health-related quality of life (HRQoL) in HD patients. We aimed to determine the prognostic importance of the Index of Disease Severity (IDS) of the Index of Coexistent Disease (ICED) scoring system as an HF severity measure.

STUDY DESIGN

Subanalysis of the Hemodialysis (HEMO) Study, a randomized controlled trial. Relationships between HF severity and mortality and cardiac hospitalizations were determined using Cox proportional hazards models. The relationship between HF severity and HRQoL scores was modeled using linear regression and generalized estimating equations.

SETTING & PARTICIPANTS

1,846 long-term HD patients at 15 clinical centers including 72 dialysis units.

PREDICTOR OR FACTOR

HF severity classified using the IDS of the ICED scoring system.

OUTCOMES

Mortality (all cause and cause specific), cardiac hospitalizations, and HRQoL.

MEASUREMENTS

All-cause, cardiac, and infectious deaths; cardiac hospitalizations; and HRQoL scores from the Kidney Disease Quality of Life-Long Form.

RESULTS

HF was present in 40% of HD patients. Increasing severity of HF was associated with older age, greater likelihood of diabetes, and lower serum albumin level (all P < 0.001). Adjusted HRs for all-cause mortality were 1.31 (95% CI, 1.12-1.53), 1.48 (95% CI, 1.19-1.85), and 2.11 (95% CI, 1.43-3.11) for mild, moderate, and severe HF, respectively (P < 0.001). All-cause, cardiac, and infectious mortality and cardiac hospitalizations increased with increasing severity of HF. Increasing HF severity was associated with decreases in HRQoL, particularly in physical functioning and sleep quality.

LIMITATIONS

This study is limited by the small sample size in the most severe HF group.

CONCLUSIONS

Increasing severity of HF is associated with increased mortality and cardiac hospitalizations and worse HRQoL, especially in perceived physical limitations. These findings emphasize the utility of the IDS of the ICED score as a valid prognostic tool for medical and HRQoL outcomes in the HD population with HF.

Predicting the risk of 1-year mortality in incident dialysis patients: accounting for case-mix severity in studies using administrative data

BACKGROUND

Administrative databases are increasingly being used to study the incident dialysis population and have important advantages. However, traditional methods of risk adjustment have limitations in this patient population.

OBJECTIVE

Our objective was to develop a prognostic index for 1-year mortality in incident dialysis patients using administrative data that was applicable to ambulatory patients, used objective definitions of candidate predictor variables, and was easily replicated in other environments.

RESEARCH DESIGN

Anonymized, administrative health data housed at the Institute for Clinical Evaluative Sciences in Toronto, Canada were used to identify a population-based sample of 16,205 patients who initiated dialysis between July 1, 1998 and March 31, 2005. The cohort was divided into derivation, validation, and testing samples and 4 different strategies were used to derive candidate logistic regression models for 1-year mortality. The final risk prediction model was selected based on discriminatory ability (as measured by the c-statistic) and a risk prediction score was derived using methods adopted from the Framingham Heart Study. Calibration of the predictive model was assessed graphically.

RESULTS

The risk of death during the first year of dialysis therapy was 16.4% in the derivation sample. The final model had a c-statistic of 0.765, 0.763, and 0.756 in the derivation, validation, and testing samples, respectively. Plots of actual versus predicted risk of death at 1-year showed good calibration.

CONCLUSION

The prognostic index and summary risk score accurately predict 1-year mortality in incident dialysis patients and can be used for the purposes of risk adjustment.

Characterizing daily life experience of patients on maintenance dialysis

BACKGROUND

Despite growing literature of the dialysis patients' high burden of illness and a compromised quality of life, little is known about their daily life experiences.

METHODS

A cross-sectional study using the day reconstruction method, an experience sampling method, was used. Seventy-one dialysis patients recruited from three dialysis centers systematically reconstructed their activities and experiences of the preceding day. Time spent on their activities, settings and associated emotions were assessed to compute U-Index scores (the percentage of time a person spent in an unpleasant or undesirable state). Patients also completed the Illness Effects Questionnaire-Self-Report (IEQ-S) and the Short-Form Health Survey-36 v2 (SF-36v2).

RESULTS

Patients spent ∼6 h of their day (excluding sleep hours) in an unpleasant or undesirable state (U-Index = 34.45 ± 29.26). U-Index scores did not differ by race, age, sex or years on dialysis and were moderately associated with IEQ-S scores (r = 0.43, P ≤ 0.001) and weakly associated with SF-36v2 physical component scores (r = -0.34, P = 0.003). U-Index scores differed significantly between dialysis days and non-dialysis days for hemodialysis patients (P = 0.012). Those who had depression or used antidepressants and reported income not meeting basic needs showed significantly higher U-Index scores than their counterparts (P < 0.05).

CONCLUSIONS

The findings may assist clinicians to better understand the daily activities and burdens experienced by dialysis patients and suggest areas for future research and clinical considerations to improve the quality of their lives.

Updated comorbidity assessments and outcomes in prevalent hemodialysis patients

When evaluating clinical characteristics and outcomes in patients on hemodialysis, the prevalence and severity of comorbidity may change over time. Knowing whether updated assessments of comorbidity enhance predictive power will assist the design of future studies. We conducted a secondary data analysis of 1846 prevalent hemodialysis patients from 15 US clinical centers enrolled in the HEMO study. Our primary explanatory variable was the Index of Coexistent Diseases score, which aggregates comorbidities, as a time-constant and time-varying covariate. Our outcomes of interest were all-cause mortality, time to first hospitalization, and total hospitalizations. We used Cox proportional hazards regression. Accounting for an updated comorbidity assessment over time yielded a more robust association with mortality than accounting for baseline comorbidity alone. The variation explained by time-varying comorbidity assessments on time to death was greater than age, baseline serum albumin, diabetes, or any other covariates. There was a less pronounced advantage of updated comorbidity assessments on determining time to hospitalization. Updated assessments of comorbidity significantly strengthen the ability to predict death in patients on hemodialysis. Future studies in dialysis should invest the necessary resources to include repeated assessments of comorbidity.

Association of residual urine output with mortality, quality of life, and inflammation in incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study

BACKGROUND

Residual kidney function (RKF) is associated with improved survival in peritoneal dialysis patients, but its role in hemodialysis patients is less well known. Urine output may provide an estimate of RKF. The aim of our study is to determine the association of urine output with mortality, quality of life (QOL), and inflammation in incident hemodialysis patients.

STUDY DESIGN

Nationally representative prospective cohort study.

SETTING & PARTICIPANTS

734 incident hemodialysis participants treated in 81 clinics; enrollment, 1995-1998; follow-up until December 2004.

PREDICTOR

Urine output, defined as producing at least 250 mL (1 cup) of urine daily, ascertained using questionnaires at baseline and year 1.

OUTCOMES & MEASUREMENTS

Primary outcomes were all-cause and cardiovascular mortality, analyzed using Cox regression adjusted for demographic, clinical, and treatment characteristics. Secondary outcomes were QOL, inflammation (C-reactive protein and interleukin 6 levels), and erythropoietin (EPO) requirements.

RESULTS

617 of 734 (84%) participants reported urine output at baseline, and 163 of 579 (28%), at year 1. Baseline urine output was not associated with survival. Urine output at year 1, indicating preserved RKF, was independently associated with lower all-cause mortality (HR, 0.70; 95% CI, 0.52-0.93; P = 0.02) and a trend toward lower cardiovascular mortality (HR, 0.69; 95% CI, 0.45-1.05; P = 0.09). Participants with urine output at baseline reported better QOL and had lower C-reactive protein (P = 0.02) and interleukin 6 (P = 0.03) levels. Importantly, EPO dose was 12,000 U/wk lower in those with urine output at year 1 compared with those without (P = 0.001).

LIMITATIONS

Urine volume was measured in only a subset of patients (42%), but agreed with self-report (P < 0.001).

CONCLUSIONS

RKF in hemodialysis patients is associated with better survival and QOL, lower inflammation, and significantly less EPO use. RKF should be monitored routinely in hemodialysis patients. The development of methods to assess and preserve RKF is important and may improve dialysis care.

Association of social support with outcomes in incident dialysis patients

BACKGROUND AND OBJECTIVES

The association of social support with outcomes in ESRD, overall and by peritoneal dialysis (PD) versus hemodialysis (HD), remains understudied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In an incident cohort of 949 dialysis patients from 77 US clinics, we examined functional social support scores (scaled 0 to 100 and categorized by tertile) both overall and in emotional, tangible, affectionate, and social interaction subdomains. Outcomes included 1-year patient satisfaction and quality of life (QOL), dialysis modality switching, and hospitalizations and mortality (through December 2004). Associations were examined using overall and modality-stratified multivariable logistic, Poisson, and Cox proportional hazards models.

RESULTS

We found that mean social support scores in this population were higher in PD versus HD patients (overall 80.5 versus 76.1; P < 0.01). After adjustment, highest versus lowest overall support predicted greater 1-year satisfaction and QOL in all patients (odds ratio 2.47 [95% confidence interval (CI) 1.18 to 5.15] and 2.06 [95% CI 1.31 to 3.22] for recommendation of center and higher mental component summary score, respectively). In addition, patients were less likely to be hospitalized (incidence rate ratio 0.86; 95% CI 0.77 to 0.98). Results were similar with subdomain scores. Modality switching and mortality did not differ by social support in these patients, and associations of social support with outcomes did not generally differ by dialysis modality.

CONCLUSIONS

Social support is important for both HD and PD patients in terms of greater satisfaction and QOL and fewer hospitalizations. Intervention studies to possibly improve these outcomes are warranted.

Inpatient hemodialysis initiation: reasons, risk factors and outcomes

BACKGROUND/AIMS

Inpatient initiation of chronic hemodialysis is considered undesirable because of cost and possible harms of hospitalization. We examined the patient characteristics and outcomes associated with inpatient initiation.

METHODS

In a prospective cohort study of incident dialysis patients, the independent association of inpatient hemodialysis initiation with patient outcomes was assessed in multivariable analyses with adjustment for patient characteristics and propensity for inpatient initiation.

RESULTS

A total of 410 of 652 (63%) hemodialysis patients began as inpatients; uremia and volume overload were the most commonly documented reasons. Compared to outpatients, inpatients were more likely to be unmarried, report less social support, have multiple comorbidities and be referred to a nephrologist 4 months or less prior to initiation. Inpatient initiation was protective for subsequent all-cause hospitalization (incidence rate ratio (IRR) = 0.92, confidence interval (CI) 0.89-0.94); this was most pronounced among those who had the highest propensity for inpatient initiation (IRR = 0.66, CI 0.56-0.78), including those referred late to nephrology. Similar results were found for infectious hospitalization. Mortality [hazard ratio = 1.03, CI 0.82-1.30] and cardiovascular events were not significantly different for inpatients versus outpatients.

CONCLUSION

Inpatient hemodialysis initiation has a protective association with hospitalization among those patients referred late to nephrology, with multiple comorbidities and/or little social support.

Correlates and outcomes of fatigue among incident dialysis patients

BACKGROUND & OBJECTIVES

Fatigue is a debilitating symptom experienced by patients undergoing dialysis, but there is only limited information on its prevalence and its association with patient outcomes. This study examines the correlates of self-reported fatigue at initiation of dialysis and after 1 yr and assesses the extent to which fatigue was associated with health-related quality of life and survival.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A longitudinal cohort of 917 incident hemodialysis and peritoneal dialysis patients who completed the CHOICE Health Experience Questionnaire (CHEQ) participated in the study. Fatigue was assessed using the SF-36 vitality scale. Known predictors of fatigue including sociodemographic and psychosocial factors, dialysis-related factors, biochemical variables including inflammatory markers, comorbidities, and medications were used as covariates.

RESULTS

A low vitality score was independently associated with white race, higher Index of Coexistent Disease score, higher body mass index, lack of physical exercise, antidepressant use, and higher C-reactive protein levels (CRP). A lower vitality score was strongly associated with lower SF-36 physical functioning, mental health, bodily pain scores, and decreased sleep quality (all P < 0.001) at baseline. Among surviving participants, higher serum creatinine at baseline was associated with preserved vitality at 1 yr. Patients with the highest baseline vitality scores were associated with longer survival (hazard ratio 0.75; 95% CI 0.58 to 0.96, P = 0.03).

CONCLUSIONS

The findings of this study demonstrate that ESRD patients experience profound levels of fatigue and elucidate its correlates. Also, the association of fatigue with survival may have significant implications for this population.

Considerations in the statistical analysis of hemodialysis patient survival

The association of hemodialysis dosage with patient survival is controversial. Here, we tested the hypothesis that methods for survival analysis may influence conclusions regarding dialysis dosage and mortality. We analyzed all-cause mortality by proportional hazards and accelerated failure time regression models in a cohort of incident hemodialysis patients who were followed for 9 yr. Both models identified age, race, heart failure, physical functioning, and comorbidity scores as important predictors of patient survival. Using proportional hazards, there was no statistically significant association between mortality and Kt/V (hazard ratio 0.72; 95% confidence interval 0.45 to 1.14). In contrast, using accelerated failure time models, each 0.1-U increment of Kt/V improved adjusted median patient survival by 3.50% (95% confidence interval 0.20 to 7.08%). Proportional hazard models also yielded less accurate estimates for median survival. These findings are consistent with an additive damage model for the survival of patients who are on hemodialysis. In this conceptual model, the assumptions of the proportional hazard model are violated, leading to underestimation of the importance of dialysis dosage. These results suggest that future studies of dialysis adequacy should consider this additive damage model when selecting methods for survival analysis. Accelerated failure time models may be useful adjuncts to the Cox model when studying outcomes of dialysis patients.

Peripheral vascular disease-related procedures in dialysis patients: predictors and prognosis

BACKGROUND AND OBJECTIVES

Peripheral vascular disease (PVD) is prevalent among dialysis patients, and many dialysis patients undergo PVD-related procedures. We aimed to examine the risk factors for and prognosis after such procedures in the dialysis setting.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a national prospective cohort study of 1041 incident dialysis patients, we examined the factors that are associated with PVD procedures (lower extremity amputations and bypasses) after the start of dialysis. Adjusted risk for PVD procedures of various factors was estimated using multivariable Cox proportional hazards models. Incidence rates of subsequent cardiovascular events, infectious hospitalizations, PVD- and cardiovascular disease-related mortality, and all-cause mortality were compared for those with and without a PVD procedure.

RESULTS

Overall, 217 (21%) patients underwent a PVD procedure after the start of dialysis. For those without diabetes, only PVD history (relative hazard [RH] 2.9; 95% confidence interval [CI] 1.3 to 6.6) and increased fibrinogen (RH 1.2; 95% CI 1.0 to 1.5) predicted PVD procedures. For those with diabetes, increased serum phosphate (RH 1.2; 95% CI 1.1 to 1.4), along with decreased albumin, increased C-reactive protein and fibrinogen, and lower SBP, was associated with risk for PVD procedures. Of those who had a procedure compared with those who did not, 68 versus 30% experienced a subsequent cardiovascular event, 85 versus 66% an infectious hospitalization, 11 versus 2% a PVD-related death, and 81 versus 59% all-cause death (mean follow-up 3.0 yr).

CONCLUSIONS

Prognosis after PVD procedures is poor, and providers should be aware that risk factors for PVD procedures may differ by diabetes status.

Association of Peritoneal Dialysis Clinic Size with Clinical Outcomes

Objective

Very few studies have addressed the relationship between number of peritoneal dialysis (PD) patients treated at a clinic (PD clinic size) and clinical outcomes. In a national prospective cohort study of incident PD patients ( n = 236, from 26 clinics), we examined whether being treated at a larger PD clinic [>50 PD patients ( n = 3 clinics) vs <50 PD patients ( n = 23 clinics)] was associated with better patient outcomes, including fewer switches to hemodialysis, fewer cardiovascular events, lower cardiovascular mortality, and lower all-cause mortality.

Methods

Multivariable Cox models were used to assess relative hazards (RHs) for modality switches, cardiovascular events, cardiovascular deaths, and all-cause deaths by PD clinic size. All models were adjusted for demographics, comorbidities, laboratory values, and clinic years in operation.

Results

Being treated at a clinic with >50 patients was associated with fewer switches to hemodialysis (RH = 0.13, 95% CI 0.06 – 0.31) and fewer cardiovascular events (RH = 0.62, 95% CI 0.06 – 0.98). No associations of PD clinic size with cardiovascular or all-cause mortality were seen.

Conclusion

PD patients treated at clinics with greater numbers of PD patients may have better outcomes in terms of technique failure and cardiovascular morbidity. PD clinic size may act as a proxy of greater PD experience, more focus on the modality, and better PD practices at the clinic, resulting in better outcomes.

A clinical score to predict 6-month prognosis in elderly patients starting dialysis for end-stage renal disease

AIM

The aim of this study was to develop and validate a prognostic score for 6-month mortality in elderly patients starting dialysis for end-stage renal disease.

METHODS

Using data from the French Rein registry, we developed a prognostic score in a training sample of 2500 patients aged 75 years or older who started dialysis between 2002 and 2006, which we validated in a similar sample of 1642 patients. Multivariate logistic regression with 500 bootstrap samples allowed us to select risk factors from 19 demographic and baseline clinical variables.

RESULTS

The overall 6-month mortality was 19%. Age was not associated with early mortality. Nine risk factors were selected and points assigned for the score were as follows: body mass index <18.5 kg/m2 (2 points), diabetes (1), congestive heart failure stages III to IV (2), peripheral vascular disease stages III to IV (2), dysrhythmia (1), active malignancy (1), severe behavioural disorder (2), total dependency for transfers (3) and unplanned dialysis (2). The median score was 2. Mortality rates ranged from 8% in the lowest risk group (0 point) to 70% in the highest risk group (> or =9 points) and 17% in the median group (2 points). Seventeen percent of all deaths occurred after withdrawal from dialysis, ranging from 0% for a score of 0-1 to 15% for a score of 7 or higher.

CONCLUSIONS

This simple clinical score effectively predicts short-term prognosis among elderly patients starting dialysis. It should help to illuminate clinical decision making, but cannot be used to withhold dialysis. It ought to only be used by nephrologists to facilitate the discussion with the patients and their families.

Cerebrovascular disease incidence, characteristics, and outcomes in patients initiating dialysis: the choices for healthy outcomes in caring for ESRD (CHOICE) study

BACKGROUND

Stroke is the third most common cause of cardiovascular disease death in patients on dialysis therapy; however, characteristics of cerebrovascular disease, including clinical subtypes and subsequent consequences, have not been well described.

STUDY DESIGN

Prospective national cohort study, the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study.

SETTINGS & PARTICIPANTS

1,041 incident dialysis patients treated in 81 clinics enrolled from October 1995 to July 1998, followed up until December 31, 2004.

PREDICTOR

Time from dialysis therapy initiation.

OUTCOMES & MEASUREMENTS

Cerebrovascular disease events were defined as nonfatal (hospitalized stroke and carotid endarterectomy) and fatal (stroke death) events after dialysis therapy initiation. Stroke subtypes were classified by using standardized criteria from the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) system. The incidence of cerebrovascular event subtypes was analyzed by using time-to-event analyses accounting for competing risk of death. Clinical outcomes after stroke were abstracted from medical records.

RESULTS

165 participants experienced a cerebrovascular event with an overall incidence of 4.9 events/100 person-years. Ischemic stroke was the most common (76% of all 200 events), with cardioembolism subtype accounting for 28% of the 95 abstracted ischemic events. Median time from onset of symptoms to first stroke evaluation was 8.5 hours (25th and 75th percentiles, 1 and 42), with only 56% of patients successfully escaping death, nursing home, or skilled nursing facility.

LIMITATIONS

Relatively small sample size limits power to determine risk factors.

CONCLUSIONS

Cerebrovascular disease is common in dialysis patients, is identified late, and carries a significant risk of morbidity and mortality. Stroke etiologic subtypes on dialysis therapy are multifactorial, suggesting risk factors may change the longer one has end-stage renal disease. Additional studies are needed to address the poor prognosis through prevention, early identification, and treatment.

Timing, causes, predictors and prognosis of switching from peritoneal dialysis to hemodialysis: a prospective study

BACKGROUND

The use of peritoneal dialysis (PD) has declined in the United States over the past decade and technique failure is also reportedly higher in PD compared to hemodialysis (HD), but there are little data in the United States addressing the factors and outcomes associated with switching modalities from PD to HD.

METHODS

In a prospective cohort study of 262 PD patients enrolled from 28 peritoneal dialysis clinics in 13 U.S. states, we examined potential predictors of switching from PD to HD (including demographics, clinical factors, and laboratory values) and the association of switching with mortality. Cox proportional hazards regression was used to assess relative hazards (RH) of switching and of mortality in PD patients who switched to HD.

RESULTS

Among 262 PD patients, 24.8% switched to HD; with more than 70% switching within the first 2 years. Infectious peritonitis was the leading cause of switching. Patients of black race and with higher body mass index were significantly more likely to switch from PD to HD, RH (95% CI) of 5.01 (1.15-21.8) for black versus white and 1.09 (1.03-1.16) per 1 kg/m2 increase in BMI, respectively. There was no difference in survival between switchers and non-switchers, RH (95% CI) of 0.89 (0.41-1.93).

CONCLUSION

Switching from PD to HD occurs early and the rate is high, threatening long-term viability of PD programs. Several patient characteristics were associated with the risk of switching. However, there was no survival difference between switchers and non-switchers, reassuring providers and patients that PD technique failure is not necessarily associated with poor prognosis.