Mortality Risk of Patients Treated in Dialysis Facilities with Payment Reductions under ESRD Quality Incentive Program

BACKGROUND

The Centers for Medicare & Medicaid Services End-Stage Renal Disease Quality Incentive Program (ESRD QIP) measures quality of care delivered by dialysis facilities and imposes Medicare payment reductions for quality lapses. We assessed the association between payment reductions and patient mortality, a quality indicator not included in the ESRD QIP measure set.

METHODS

Association between mortality and ESRD QIP facility payment reduction based on the year of performance was expressed as the unadjusted rate and patient case-mix-adjusted hazard ratio. We also measured association between mortality and 1-year changes in payment reductions. Retrospective patient cohorts were defined by their treating dialysis facility on the first day of each year (2010-2018).

RESULTS

Facility performance resulted in payment reductions for 5%-42% of dialysis facilities over the 9 study years. Patients experienced progressively higher mortality at each payment reduction level. Across all years, unadjusted mortality was 17.3, 18.1, 18.9, 20.3, and 23.9 deaths per 100 patient-years for patients in facilities that received 0%, 0.5%, 1%, 1.5%, and 2% payment reductions, respectively. The adjusted hazard ratio showed a similar stepwise pattern by the level of payment reduction: 1.0 (reference), 1.08 (95% confidence interval [CI], 1.07 to 1.09), 1.15 (95% CI, 1.13 to 1.16), 1.19 (95% CI, 1.16 to 1.21), and 1.34 (95% CI, 1.29 to 1.39). Strength of the association increased from 2010 to 2016. Patients treated in facilities that improved over 1 year generally experienced lower mortality; patients in facilities that performed worse on ESRD QIP measures generally experienced higher mortality.

CONCLUSIONS

Patient mortality was associated with ESRD QIP facility payment reductions in dose-response and temporal patterns.

Peritoneal Dialysis-Associated Peritonitis Trends Using Medicare Claims Data, 2013-2017

RATIONALE & OBJECTIVE

The occurrence and consequences of peritoneal dialysis (PD)-associated peritonitis limit its use in populations with kidney failure. Studies of large clinical populations may enhance our understanding of peritonitis. To facilitate these studies we developed an approach to measuring peritonitis rates using Medicare claims data to characterize peritonitis trends and identify its clinical risk factors.

STUDY DESIGN

Retrospective cohort study of PD-associated peritonitis.

SETTING & PARTICIPANTS

US Renal Data System standard analysis files were used for claims, eligibility, modality, and demographic information. The sample consisted of patients receiving PD treated at some time between 2013 and 2017 who were covered by Medicare fee-for-service (FFS) insurance with paid claims for dialysis or hospital services.

EXPOSURES/PREDICTORS

Peritonitis risk was characterized by year, age, sex, race, ethnicity, vintage of kidney replacement therapy, cause of kidney failure, and prior peritonitis episodes.

OUTCOME

The major outcome was peritonitis, identified using ICD-9 and ICD-10 diagnosis codes. Closely spaced peritonitis claims (30 days) were aggregated into 1 peritonitis episode.

ANALYTICAL APPROACH

Patient-level risk factors for peritonitis were modeled using Poisson regression.

RESULTS

We identified 70,271 peritonitis episodes from 396,289 peritonitis claims. Although various codes were used to record an episode of peritonitis, none was used predominantly. Peritonitis episodes were often identified by multiple aggregated claims, with the mean and median claims per episode being 5.6 and 2, respectively. We found 40% of episodes were exclusively outpatient, 9% exclusively inpatient, and 16% were exclusively based on codes that do not clearly distinguish peritonitis from catheter infections/inflammation ("catheter codes"). The overall peritonitis rate was 0.54 episodes per patient-year (EPPY). The rate was 0.45 EPPY after excluding catheter codes and 0.35 EPPY when limited to episodes that only included claims from nephrologists or dialysis providers. The peritonitis rate declined by 5%/year and varied by patient factors including age (lower rates at higher ages), race (Black > White>Asian), and prior peritonitis episodes (higher rate with each prior episode).

LIMITATIONS

Coding heterogeneity indicates a lack of standardization. Episodes based exclusively on catheter codes could represent false positives. Peritonitis episodes were not validated against symptoms or microbiologic data.

CONCLUSIONS

PD-associated peritonitis rates decline over time and were lower among older patients. A claims-based approach offers a promising framework for the study of PD-associated peritonitis.

Hemoglobin and Clinical Outcomes in Hemodialysis: An Analysis of US Medicare Data From 2018 to 2020

Rationale & Objective

Anemia management in patients treated with maintenance dialysis remains a challenge. We sought to update information in this area by evaluating the association between hemoglobin and various outcome and utilization measures using data-rich Medicare sources.

Study Design

Observational cohort study using data from the Consolidated Renal Operations in a Web-enabled Network and Medicare claims.

Setting & Participants

We studied 371,250 prevalent patients treated with hemodialysis, covering 3,326,072 patient-months in 2019.

Exposure

Monthly patient hemoglobin concentrations.

Outcomes

We examined several outcomes, including mortality, all-cause hospitalization, cause-specific hospitalization, and emergency department utilization in the month following the exposure measurement.

Analytical Approach

For each monthly observation period, we calculated unadjusted and adjusted (for demographics and comorbid condition) hazard ratios using Cox regression.

Results

The hemoglobin concentration was <10.5 g/dL for 40% of observations. We found an inverse association between mortality and hemoglobin measured over a range from <9 g/dL (HR, 2.53; 95% CI, 2.45-2.61; P < 0.0001, reference = 10.5-11 g/dL) to 11-11.5 g/dL (HR, 0.92; 95% CI, 0.89-0.96; P < 0.0001). Mortality risk started to increase at hemoglobin levels >11.5 g/dL. All-cause hospitalization, cause-specific hospitalization (including cardiovascular, infection, and several subcategories including coronavirus disease 2019 hospitalization), and emergency department utilization were inversely associated with hemoglobin concentration, with risk reduction stabilizing at hemoglobin levels of approximately 11.5-12 g/dL and higher.

Limitations

As with prior observational studies, the observed associations are not necessarily causal.

Conclusions

In a large US hemodialysis population, there were better clinical outcomes at higher hemoglobin concentrations over short exposure and follow-up periods, consistent with other observational studies that generally used longer exposure and follow-up times. Mortality risk increased at hemoglobin concentrations >11.5 g/dL, consistent with findings from erythropoiesis-stimulating agent clinical trials. The apparently beneficial short-term effects associated with higher hemoglobin concentrations suggest that hemoglobin measurements capture unmeasured elements of patient risk.

Kidney Health Initiative ESKD Data Standards Project

The end-stage kidney disease (ESKD) Data Standards Project was launched by the Kidney Health Initiative (KHI) with the goal of standardizing dialysis-related measurements for research use. KHI is a public-private partnership between the American Society of Nephrology, US Food and Drug Administration, and organizations with an interest in kidney disease. KHI promotes safe and effective patient-centered therapies for people with kidney disease. In 2018, KHI established a workgroup with expertise in nephrology, nursing, quality management, ESKD data, organizational management, and clinical research. The workgroup identified 5 topic areas and 8 specific measures for the development of standards on the basis of the existing ESKD Measurement Specification Manual published by the Centers for Medicare & Medicaid Services. The topic areas were ultrafiltration rate, vascular access, dialysis small solute clearance (3 data standards), hospitalization (2 data standards), and mortality. The research standards were approved by the workgroup, reviewed by external reviewers, and opened to public comment. The data standards attempt to achieve balance between brevity and completeness in the face of knowledge gaps. The ESKD Data Standards are publicly available on the KHI website (https://khi.asn-online.org/projects/project.aspx?ID=78).

Secondary hyperparathyroidism, weight loss, and longer term mortality in haemodialysis patients: results from the DOPPS

BACKGROUND

Wasting is a common complication of kidney failure that leads to weight loss and poor outcomes. Recent experimental data identified parathyroid hormone (PTH) as a driver of adipose tissue browning and wasting, but little is known about the relations among secondary hyperparathyroidism, weight loss, and risk of mortality in dialysis patients.

METHODS

We included 42,319 chronic in-centre haemodialysis patients from the Dialysis Outcomes and Practice Patterns Study phases 2-6 (2002-2018). Linear mixed models were used to estimate the association between baseline PTH and percent weight change over 12 months, adjusting for country, demographics, comorbidities, and labs. Accelerated failure time models were used to assess 12 month weight loss as a mediator between baseline high PTH and mortality after 12 months.

RESULTS

Baseline PTH was inversely associated with 12 month weight change: 12 month weight loss >5% was observed in 21%, 18%, 18%, 17%, 15%, and 14% of patients for PTH ≥600 pg/mL, 450-600, 300-450, 150-300, 50-150, and <50 pg/mL, respectively. In adjusted analyses, 12 month weight change compared with PTH 150-299 pg/mL was -0.60%, -0.12%, -0.10%, +0.15%, and +0.35% for PTH ≥600, 450-600, 300-450, 50-150, and <50 pg/mL, respectively. This relationship was robust regardless of recent hospitalization and was more pronounced in persons with preserved appetite. During follow-up after the 12 month weight measure [median, 1.0 (interquartile range, 0.6-1.7) years; 6125 deaths], patients with baseline PTH ≥600 pg/mL had 11% [95% confidence interval (CI), 9-13%] shorter lifespan, and 18% (95% CI, 14-23%) of this effect was mediated through weight loss ≥2.5%.

CONCLUSIONS

Secondary hyperparathyroidism may be a novel mechanism of wasting, corroborating experimental data, and, among chronic dialysis patients, this pathway may be a mediator between elevated PTH levels and mortality. Future research should determine whether PTH-lowering therapy can limit weight loss and improve longer term dialysis outcomes.

The risk of medically uncontrolled secondary hyperparathyroidism depends on parathyroid hormone levels at haemodialysis initiation

BACKGROUND

Optimal parathyroid hormone (PTH) control during non-dialysis chronic kidney disease (ND-CKD) might decrease the subsequent risk of parathyroid hyperplasia and uncontrolled secondary hyperparathyroidism (SHPT) on dialysis. However, the evidence for recommending PTH targets and therapeutic strategies is weak for ND-CKD. We evaluated the patient characteristics, treatment patterns and PTH control over the first year of haemodialysis (HD) by PTH prior to HD initiation.

METHODS

We studied 5683 incident HD patients from 21 countries in Dialysis Outcomes and Practice Patterns Study Phases 4-6 (2009-18). We stratified by PTH measured immediately prior to HD initiation and reported the monthly prescription prevalence of active vitamin D and calcimimetics over the first year of HD and risk of PTH >600 pg/mL after 9-12 months on HD.

RESULTS

The 16% of patients with PTH >600 pg/mL prior to HD initiation were more likely to be prescribed active vitamin D and calcimimetics during the first year of HD. The prevalence of PTH >600 pg/mL 9-12 months after start of HD was greater for patients who initiated HD with PTH >600 (29%) versus 150-300 (7%) pg/mL (adjusted risk difference: 19%; 95% confidence interval : 15%, 23%). The patients with sustained PTH >600 pg/mL after 9-12 months on HD were younger, more likely to be black, and had higher serum phosphorus and estimated glomerular filtration rates at HD initiation.

CONCLUSIONS

Increased PTH before HD start predicted a higher PTH level 9-12 months later, despite greater use of active vitamin D and calcimimetics. More targeted PTH control during ND-CKD may influence outcomes during HD, raising the need for PTH target guidelines in these patients.

The Study of Outcomes for Capd versus Hemodialysis Patients

Objective

To discuss potential reasons for reported differences in the results of several recent studies comparing mortality risk among continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis patients, and to assess the role of statistical methods and study design.

Data Sources

Recent published reports comparing mortality risk among patients treated with CAPD and hemodialysis.

Conclusions

Differences in study design, study populations, sample size, data collection, and availability of data likely account in part for the differences in available study results. The Cox model is a valuable tool, particularly for observational studies. Observed outcome differences for CAPD and hemodialysis patients may be due to either the dialytic modality itself or other factors such as differences in patient selection, practice patterns, dialysis dose, patient compliance, etc. Relative mortality rates for hemodialysis and CAPD patients may vary by country, as these factors may differ internationally. A randomized clinical trial is necessary to best determine the effect of the modality itself.

International variation in the management of mineral bone disorder in patients with chronic kidney disease: Results from CKDopps

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is commonly associated with mineral and bone metabolism disorders, but these are less frequently studied in non-dialysis CKD patients than in dialysis patients. We examined and described international variation in mineral and bone disease (MBD) markers and their treatment and target levels in Stage 3-5 CKD patients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Prospective cohort study of 7658 adult patients with eGFR <60mL/min/1.73m², excluding dialysis or transplant patients, participating in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) in Brazil, France, Germany, and the US. CKD-MBD laboratory markers included serum levels of phosphorus (P), calcium (Ca), intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D (25-D). MBD treatment data included phosphate binders and vitamin D (nutritional and active). Nephrologist survey data were collected on target MBD marker levels.

RESULTS

Over two-thirds of the patients had MBD markers measured at time intervals in line with practice guidelines. P and iPTH increased and Ca decreased gradually from eGFR 60-20mL/min/1.73m² and more sharply for eGFR<20. 25-D showed no relation to eGFR. Nephrologist survey data indicated marked variation in upper target P and iPTH levels. Among patients with P>5.5mg/dL, phosphate binder use was 14% to 43% across the four countries. Among patients with PTH >300pg/mL, use of active (calcitriol and related analogs) vitamin D was 12%-51%, and use of any (active or nutritional) vitamin D was 60%-87%.

CONCLUSIONS

Although monitoring of CKD-MBD laboratory markers by nephrologists in CKDopps countries is consistent with guidelines, target levels vary notably and prescription of medications to treat abnormalities in these laboratory markers is generally low in these cross-sectional analyses. While there are opportunities to increase treatment of hyperphosphatemia, hyperparathyroidism, and vitamin D deficiency in advanced CKD, the effect on longer-term complications of these conditions requires study.

Peritoneal Dialysis Patient Outcomes under the Medicare Expanded Dialysis Prospective Payment System

BACKGROUND AND OBJECTIVES

Peritoneal dialysis (PD) use increased in the United States with the introduction of a new Medicare prospective payment system in January 2011 that likely reduced financial disincentives for facility use of this home therapy. The expansion of PD to a broader population and facilities having less PD experience may have implications for patient outcomes. We assessed the impact of PD expansion on PD discontinuation and patient mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A prospective cohort study was conducted of patients treated with PD at 90 days of ESKD. Patients were grouped by study start date relative to the Medicare payment reform: prereform (July 1, 2008 to December 31, 2009; n=10,585), interim (January 1, 2010 to December 31, 2010; n=7832), and reform period (January 1, 2011 to December 31, 2012; n=18,742). Patient characteristics and facility PD experience were compared at baseline (day 91 of ESKD). Patients were followed for 3 years for the major outcomes of PD discontinuation and mortality using Cox proportional hazards models.

RESULTS

Patient characteristics, including age, sex, race, ethnicity, rurality, cause of ESKD, and comorbidity, were similar or showed small changes across the three study periods. There was an increasing tendency for patients on PD to be treated in facilities with less PD experience (from 34% during the prereform period being treated in facilities averaging <14 patients on PD per year to 44% in the reform period). Patients treated in facilities with less PD experience had a higher rate of PD discontinuation than patients treated in facilities with the most experience (hazard ratio [HR], 1.16; 95% confidence interval [95% CI], 1.10 to 1.23 for the first versus fifth quintile of PD experience). Nevertheless, the risk of PD discontinuation fell during the late interim period (HR, 0.88; 95% CI, 0.82 to 0.95) and most of the reform period (from HR, 0.85; 95% CI, 0.79 to 0.91 to HR, 0.94; 95% CI, 0.87 to 1.01). Mortality risk was stable across the three study periods.

CONCLUSIONS

In the context of expanding PD use and declining facility PD experience, the risk of PD discontinuation fell, and there was no adverse effect on mortality.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_09_12_CJN01610219.mp3.

Indirect human impacts reverse centuries of carbon sequestration and salt marsh accretion

Direct and indirect human impacts on coastal ecosystems have increased over the last several centuries, leading to unprecedented degradation of coastal habitats and loss of ecological services. Here we document a two-century temporal disparity between salt marsh accretion and subsequent loss to indirect human impacts. Field surveys, manipulative experiments and GIS analyses reveal that crab burrowing weakens the marsh peat base and facilitates further burrowing, leading to bank calving, disruption of marsh accretion, and a loss of over two centuries of sequestered carbon from the marsh edge in only three decades. Analogous temporal disparities exist in other systems and are a largely unrecognized obstacle in attaining sustainable ecosystem services in an increasingly human impacted world. In light of the growing threat of indirect impacts worldwide and despite uncertainties in the fate of lost carbon, we suggest that estimates of carbon emissions based only on direct human impacts may significantly underestimate total anthropogenic carbon emissions.

Effect of ionized serum calcium on outcomes in acute kidney injury needing renal replacement therapy: secondary analysis of the acute renal failure trial network study

BACKGROUND

Hypocalcemia is very common in critically ill patients. While the effect of ionized calcium (iCa) on outcome is not well understood, manipulation of iCa in critically ill patients is a common practice. We analyzed all-cause mortality and several secondary outcomes in patients with acute kidney injury (AKI) by categories of serum iCa among participants in the Acute Renal Failure Trial Network (ATN) Study.

METHODS

This is a post hoc secondary analysis of the ATN Study which was not preplanned in the original trial. Risk of mortality and renal recovery by categories of iCa were compared using multiple fixed and adjusted time-varying Cox regression models. Multiple linear regression models were used to explore the impact of baseline iCa on days free from ICU and hospital.

RESULTS

A total of 685 patients were included in the analysis. Mean age was 60 (SD=15) years. There were 502 male patients (73.3%). Sixty-day all-cause mortality was 57.0%, 54.8%, and 54.4%, in patients with an iCa<1, 1-1.14, and ≥1.15 mmol/L, respectively (p=0.87). Mean of days free from ICU or hospital in all patients and the 28-day renal recovery in survivors to Day 28 were not significantly different by categories of iCa. The hazard for death in a fully adjusted time-varying Cox regression survival model was 1.7 (95% CI: 1.3-2.4) comparing iCa<1 to iCa≥1.15 mmol/L. No outcome was different for levels of iCa>1 mmol/L.

CONCLUSION

Severe hypocalcemia with iCa<1 mmol/L independently predicted mortality in patients with AKI needing renal replacement therapy.

New England salt marsh recovery: opportunistic colonization of an invasive species and its non-consumptive effects

Predator depletion on Cape Cod (USA) has released the herbivorous crab Sesarmareticulatum from predator control leading to the loss of cordgrass from salt marsh creek banks. After more than three decades of die-off, cordgrass is recovering at heavily damaged sites coincident with the invasion of green crabs (Carcinusmaenas) into intertidal Sesarma burrows. We hypothesized that Carcinus is dependent on Sesarma burrows for refuge from physical and biotic stress in the salt marsh intertidal and reduces Sesarma functional density and herbivory through consumptive and non-consumptive effects, mediated by both visual and olfactory cues. Our results reveal that in the intertidal zone of New England salt marshes, Carcinus are burrow dependent, Carcinus reduce Sesarma functional density and herbivory in die-off areas and Sesarma exhibit a generic avoidance response to large, predatory crustaceans. These results support recent suggestions that invasive Carcinus are playing a role in the recovery of New England salt marshes and assertions that invasive species can play positive roles outside of their native ranges.

Estimating prevalence of CKD stages 3-5 using health system data

BACKGROUND

The feasibility of using health system data to estimate prevalence of chronic kidney disease (CKD) stages 3-5 was explored.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

A 5% national random sample of patients from the Veterans Affairs (VA) health care system, enrollees in a managed care plan in Michigan (M-CARE), and participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES).

PREDICTOR

Observed CKD prevalence estimates in the health system population were calculated as patients with an available outpatient serum creatinine measurement with estimated glomerular filtration rate <60 mL/min/1.73 m(2), among those with at least one outpatient visit during the year.

OUTCOMES & MEASUREMENTS

A logistic regression model was fitted using data from the 2005-2006 NHANES to predict CKD prevalence in those untested for serum creatinine in the health system population, adjusted for demographics and comorbid conditions. Model results then were combined with the observed prevalence in tested patients to derive an overall predicted prevalence of CKD within the health systems.

RESULTS

Patients in the VA system were older, had more comorbid conditions, and were more likely to be tested for serum creatinine than those in the M-CARE system. Observed prevalences of CKD stages 3-5 were 15.6% and 0.9% in the VA and M-CARE systems, respectively. Using data from NHANES, the overall predicted prevalences of CKD were 20.4% and 1.6% in the VA and M-CARE systems, respectively.

LIMITATIONS

Health system data quality was limited by missing data for laboratory results and race. A single estimated glomerular filtration rate value was used to define CKD, rather than persistence over 3 months.

CONCLUSIONS

Estimation of CKD prevalence within health care systems is feasible, but discrepancies between observed and predicted prevalences suggest that this approach is dependent on data availability and quality of information for comorbid conditions, as well as the frequency of testing for CKD in the health care system.

Atrial fibrillation in hemodialysis patients: clinical features and associations with anticoagulant therapy

Using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS), we determined incidence, prevalence, and outcomes among hemodialysis patients with atrial fibrillation. Cox proportional hazards models, to identify associations with newly diagnosed atrial fibrillation and clinical outcomes, were stratified by country and study phase and adjusted for descriptive characteristics and comorbidities. Of 17,513 randomly sampled patients, 2188 had preexisting atrial fibrillation, with wide variation in prevalence across countries. Advanced age, non-black race, higher facility mean dialysate calcium, prosthetic heart valves, and valvular heart disease were associated with higher risk of new atrial fibrillation. Atrial fibrillation at study enrollment was positively associated with all-cause mortality and stroke. The CHADS2 score identified approximately equal-size groups of hemodialysis patients with atrial fibrillation with low (less than 2) and higher risk (more than 4) for subsequent strokes on a per 100 patient-year basis. Among patients with atrial fibrillation, warfarin use was associated with a significantly higher stroke risk, particularly in those over 75 years of age. Our study shows that atrial fibrillation is common and associated with elevated risk of adverse clinical outcomes, and this risk is even higher among elderly patients prescribed warfarin. The effectiveness and safety of warfarin in hemodialysis patients require additional investigation.

Early readmission and length of hospitalization practices in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Rising hospital care costs have created pressure to shorten hospital stays and emphasize outpatient care. This study tests the hypothesis that shorter median length of stay (LOS) as a dialysis facility practice is associated with higher rates of early readmission.

METHODS

Readmission within 30 days of each hospitalization was evaluated for participants in the Dialysis Outcomes and Practice Patterns Study, an observational study of randomly selected hemodialysis patients in the United States (142 facilities, 5095 patients with hospitalizations), five European countries (101 facilities, 2281 patients with hospitalizations), and Japan (58 facilities, 883 patients with hospitalizations). Associations between median facility LOS (estimated from all hospitalizations at the facility and interpreted as a dialysis facility practice pattern) and odds of readmission were assessed using logistic regression, adjusted for patient characteristics and the LOS of each index hospitalization.

RESULTS

Risk of readmission was directly and significantly associated with LOS of the index hospitalization (adjusted odds ratio [AOR] 1.005 per day in median facility LOS, p = 0.007) and inversely associated with median facility LOS (AOR = 0.974 per day, p = 0.016). This latter association was strongest for US hemodialysis centers (AOR = 0.954 per day, p = 0.015).

CONCLUSIONS

Dialysis facilities with shorter median hospital LOS for their patients have higher odds of readmission, particularly in the United States, where there is greater pressure to shorten LOS. The determinants and consequences of practices related to hospital LOS for hemodialysis patients should be further studied.

Establishing a national chronic kidney disease surveillance system for the United States

Despite the recognized importance of chronic kidney disease (CKD), the United States currently lacks a comprehensive, systematic surveillance program that captures and tracks all aspects of CKD in the population. As part of its CKD Initiative, the Centers for Disease Control and Prevention (CDC) funded two teams to jointly initiate the development of a CKD surveillance system. Here, we describe the process and methods used to establish this national CDC CKD Surveillance System. The major CKD components covered include burden (incidence and prevalence), risk factors, awareness, health consequences, processes and quality of care, and health system capacity issues. Goals include regular reporting of the data collected, plus development of a dynamic project web site and periodic issuance of a CKD fact sheet. We anticipate that this system will provide an important foundation for widespread efforts toward primary prevention, earlier detection, and implementation of optimal disease management strategies, with resultant increased awareness of CKD, decreased rates of CKD progression, lowered mortality, and reduced resource utilization. Final success will be measured by usage, impact, and endorsement.

Prescription of antihypertensive agents to haemodialysis patients: time trends and associations with patient characteristics, country and survival in the DOPPS

BACKGROUND

Haemodialysis patients were studied in 12 countries to identify practice patterns of prescription of antihypertensive agents (AHA) associated with survival.

METHODS

The sample included 28 513 patients enrolled in DOPPS I and II. The classes of AHA studied were beta blocker (BB), angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), peripheral blocker, central antagonist, vasodilator, long-acting dihydropyridine calcium channel blocker (CCB), short-acting dihydropyridine CCB and non-dihydropyridine CCB. To reduce bias due to unmeasured confounders, the associations with mortality were assessed by separate Cox models based on patient-level prescription and facility prescription practice.

RESULTS

An increase in prescription of ARBs (9.5%) and BBs (9.1%) was observed from DOPPS I to II. Prescription of AHA classes varied significantly by country, ranging for BBs from 9.7% in Japan to 52.7% in Sweden and for ARBs from 5.5% in Italy to 21.3% in Japan in DOPPS II. Facilities that treated 10% more patients with ARBs had, on average, 7% lower all-cause mortality, independent of patient characteristics and the prescription patterns of other antihypertensive medications (P = 0.05). Significant and independent associations with reduction in cardiovascular mortality were observed for ARBs (RR = 0.79; P = 0.005) and BBs (RR = 0.87, P = 0.004) in analyses of patient-level prescriptions. These associations in the facility-level model followed the same direction.

CONCLUSIONS

DOPPS data show large variations across countries in AHA prescription for haemodialysis patients. The data suggest an association between ARB use and reduction in all-cause mortality, as well as with the use of BBs and reduction in cardiovascular mortality among haemodialysis patients.

Rosiglitazone is associated with mortality in chronic hemodialysis patients

Recent studies have associated rosiglitazone, a thiazolidinedione drug, with adverse cardiovascular outcomes in the general population with diabetes. Using data from the Dialysis Outcomes and Practice Patterns Study in the United States, we examined cardiovascular hospitalization and mortality associated with prescription of rosiglitazone, compared with other oral hypoglycemic agents, among 2393 long-term hemodialysis patients who were followed for a median of 1.1 yr. We assessed mortality risk using Cox models in patient-level and dialysis facility-level analyses that used the facility proportion of patients on rosiglitazone as the predictor (instrumental variable approach) and adjusted the models for demographics, comorbid conditions, laboratory values, and achieved dialysis dosage. Compared with patients prescribed other oral hypoglycemic agents, patients prescribed rosiglitazone had significantly higher all-cause (hazard ratio [HR] 1.38; 95% confidence interval [CI] 1.05 to 1.82) and cardiovascular (HR 1.59; 95% CI 1.14 to 2.22) mortality, and their adjusted HR for hospitalization with myocardial infarction was 3.5-fold higher (P = 0.02). We did not observe similar associations in a secondary analysis evaluating pioglitazone. By the instrumental variable approach, facilities with more than the median adjusted percentage (6.2%) of patients who had diabetes and were prescribed rosiglitazone had significantly higher all-cause mortality (HR 1.36; 95% CI 1.15 to 1.62) and cardiovascular mortality (HR 1.42; 95% CI 1.07 to 1.88) than facilities with less than the median expected percentage prescribed rosiglitazone. Our practice-based findings suggest significant associations of rosiglitazone use with higher cardiovascular and all-cause mortality among hemodialysis patients with diabetes.

The survival advantage for haemodialysis patients taking vitamin D is questioned: findings from the Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Retrospective studies of haemodialysis patients from large dialysis organizations in the United States have indicated that intravenous vitamin D may be associated with a survival benefit. However, patients prescribed vitamin D are generally healthier than those who are not, suggesting that treatment by indication may have biased previous findings. Additionally, no survival benefit associated with vitamin D has been shown in a recent meta-analysis in CKD patients. Because treatment-by-indication bias due to both measured and unmeasured confounders cannot be completely accounted for in standard regression or marginal structural models (MSMs), this study evaluates the association between vitamin D and mortality among participants in the Dialysis Outcomes and Practice Patterns Study (DOPPS) using standard regression and MSMs with an expanded set of covariates, as well as by instrumental variable models to minimize potential bias due to unmeasured confounders.

METHODS

Data from 38 066 DOPPS participants from 12 countries between 1996 and 2007 were analysed. Mortality risk was assessed using standard baseline and time-varying Cox regression models, adjusted for demographics and detailed comorbidities, and MSMs. In models similar to instrumental variable analysis, the facility percentage of patients prescribed vitamin D, adjusted for the patient case mix, was used to predict patient-level mortality.

RESULTS

Vitamin D prescription was significantly higher in the USA compared to other countries. On average, patients prescribed vitamin D had fewer comorbidities compared to those who were not. Vitamin D therapy was associated with lower mortality in adjusted time-varying standard regression models [relative ratio (RR) = 0.92 (95% confidence interval: 0.87-0.96)] and baseline MSMs [RR = 0.84 (0.78-0.98)] and time-varying MSMs [RR = 0.78 (0.73-0.84)]. No significant differences in mortality were observed in adjusted baseline standard regression models for patients with or without vitamin D prescription [RR = 0.98 (0.93-1.02)] or for patients in facility practices where vitamin D prescription was more frequent [RR for facilities in 75th versus 25th percentile of vitamin D prescription = 0.99 (0.94-1.04)].

CONCLUSIONS

Vitamin D was associated with a survival benefit in models prone to bias due to unmeasured confounding. In agreement with a meta-analysis of randomized controlled studies, no difference in mortality was observed in instrumental variable models that tend to be more independent of unmeasured confounding. These findings indicate that a randomized controlled trial of vitamin D and clinical outcomes in haemodialysis patients are needed and can be ethically conducted.

High alkaline phosphatase levels in hemodialysis patients are associated with higher risk of hospitalization and death

We evaluated risks associated with elevated alkaline phosphatase in hemodialysis patients using longitudinal data from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of hemodialysis patients in 12 countries. Alkaline phosphatase levels were normalized by the upper limit of the laboratory-reported reference range. Cause-specific hospitalization and mortality risks were evaluated using Cox proportional hazards models, stratified by region and adjusted for phosphorus, calcium, albumin, parathyroid hormone, case mix, and numerous comorbidities. The odds of high normalized alkaline phosphatase were increased twofold in the United States in comparison to Japan. Elevations of normalized alkaline phosphatase were significantly associated with several comorbid conditions, increased fractures, parathyroidectomy, risk of hospitalization due to major adverse cardiac events, higher all-cause cardiovascular, and infection-related mortality risk. Our results also show that elevated serum normalized alkaline phosphatase was associated with higher risks of hospitalization and death in hemodialysis patients, independent of calcium, phosphorus, and parathyroid hormone levels.

Mortality risk for dialysis patients with different levels of serum calcium, phosphorus, and PTH: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Abnormalities in serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations are common in patients with chronic kidney disease and have been associated with increased morbidity and mortality. No clinical trials have been conducted to clearly identify categories of calcium, phosphorus, and PTH levels associated with the lowest mortality risk. Current clinical practice guidelines are based largely on expert opinions, and clinically relevant differences exist among guidelines across countries. We sought to describe international trends in calcium, phosphorus, and PTH levels during 10 years and identify mortality risk categories in the Dialysis Outcomes and Practice Patterns Study (DOPPS), an international study of hemodialysis practices and associated outcomes.

STUDY DESIGN

Prospective cohort study.

PARTICIPANTS

25,588 patients with end-stage renal disease on hemodialysis therapy for longer than 180 days at 925 facilities in DOPPS I (1996-2001), DOPPS II (2002-2004), or DOPPS III (2005-2007).

PREDICTORS

Serum calcium, albumin-corrected calcium (Ca(Alb)), phosphorus, and PTH levels.

OUTCOMES

Adjusted hazard ratios for all-cause and cardiovascular mortality calculated using Cox models.

RESULTS

Distributions of mineral metabolism markers differed across DOPPS countries and phases, with lower calcium and phosphorus levels observed in the most recent phase of DOPPS. Survival models identified categories with the lowest mortality risk for calcium (8.6 to 10.0 mg/dL), Ca(Alb) (7.6 to 9.5 mg/dL), phosphorus (3.6 to 5.0 mg/dL), and PTH (101 to 300 pg/mL). The greatest risk of mortality was found for calcium or Ca(Alb) levels greater than 10.0 mg/dL, phosphorus levels greater than 7.0 mg/dL, and PTH levels greater than 600 pg/mL and in patients with combinations of high-risk categories of calcium, phosphorus, and PTH.

LIMITATIONS

Because of the observational nature of DOPPS, this study can only indicate an association between mineral metabolism categories and mortality.

CONCLUSIONS

Our results provide important information about mineral metabolism trends in hemodialysis patients in 12 countries during a decade. The risk categories identified in the DOPPS cohort may be relevant to efforts at international harmonization of existing clinical guidelines for mineral metabolism.

Out-of-pocket spending and medication adherence among dialysis patients in twelve countries

Few studies have examined drug costs and adherence in similar patient cohorts across countries. Using representative samples of hemodialysis patients from twelve countries, we examined out-of-pocket medication spending and cost-related nonadherence. Mean monthly spending ranged from $8 in the United Kingdom to $114 in the United States. The proportion of patients reporting nonadherence because of cost ranged from 3 percent in Japan to 29 percent in the United States. Out-of-pocket spending was related to national pharmaceutical financing policies and predicted national nonadherence rates. However, inconsistencies in the relationship between patient costs and nonadherence suggested that other social or policy factors also matter.

Aspirin prescription and outcomes in hemodialysis patients: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

We investigated aspirin-prescribing patterns and potential benefits on cardiovascular morbidity and mortality in hemodialysis patients.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Data included 28,320 randomly selected hemodialysis patients from the Dialysis Outcomes and Practice Patterns Study I and II.

PREDICTOR

Aspirin prescription at study baseline.

OUTCOMES & MEASUREMENTS

Prescription was investigated by means of logistic regression. All-cause mortality, all-cause hospitalization, cardiac event, myocardial infarction, cerebrovascular (CVA), gastrointestinal bleed, transient ischemic attack, and subdural hematoma were examined. Cox regression examined the risk of mortality and hospitalization. All models accounted for facility clustering and demographics and comorbid conditions.

RESULTS

Wide variation was found in aspirin prescription, from 8% in Japan to 41% in Australia and New Zealand. Characteristics significantly associated with increased odds of prescription included coronary artery disease, cerebrovascular disease, diabetes, male sex, nonblack race, peripheral vascular disease, age, hypertension, and absence of gastrointestinal bleeding. Aspirin was associated with decreased risk of stroke in all patients (relative risk [RR], 0.82; P < 0.01) and increased risk of myocardial infarction (RR, 1.21; P = 0.01) and cardiac event (RR, 1.08; P < 0.01) in all patients, with similar results for patients with coronary artery disease. There was no increase in gastrointestinal bleeding.

LIMITATIONS

Observational studies are not protected from biases, despite adjustments. There is potential for aspirin use to be underreported because of its availability without prescription.

CONCLUSIONS

The hypothesis that prescribing aspirin to hemodialysis patients decreases cardiovascular disease risk is not supported. Aspirin might decrease CVA and appears not to increase hemorrhagic risk. This should be an incentive for randomized controlled trials.

Diuretic use, residual renal function, and mortality among hemodialysis patients in the Dialysis Outcomes and Practice Pattern Study (DOPPS)

BACKGROUND

Information about residual renal function (RRF) and outcomes associated with practices of diuretic use in patients with end-stage renal disease is not available worldwide.

METHODS

Diuretic use was investigated in 16,420 hemodialysis patients from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of hemodialysis patients selected from nationally representative facilities on 3 continents. Logistic regressions were used to investigate associations between diuretic use and patient characteristics. Outcomes of interdialytic weight gain, increased serum potassium and phosphorus levels, and odds of retaining RRF after 1 year were investigated. Cox regression was used to analyze the association between mortality and diuretic use.

RESULTS

Facility diuretic use varied substantially from 0% to 83.9% of patients. Diuretic use decreased sharply after the start of dialysis therapy. Loop diuretic use ranged from 9.2% in the United States to 21.3% in Europe, whereas use within 90 days of starting dialysis therapy ranged from 25.0% in the United States to 47.6% in Japan. Diuretic use was associated with lower interdialytic weight gain and lower odds of hyperkalemia (potassium > 6.0 mmol/L). Patients with RRF on diuretic therapy had almost twice the odds of retaining RRF after 1 year in the study versus patients not on diuretic therapy. Patients administered diuretics had a 7% lower all-cause mortality risk (P = 0.12) and 14% lower cardiac-specific mortality risk (P = 0.03) versus patients not administered diuretics.

CONCLUSION

Variation exists in facility practices of diuretic use. In patients with RRF, there may be benefit associated with continuing diuretic use rather than automatically discontinuing diuretic therapy at dialysis initiation.

Factors associated with health-related quality of life among hemodialysis patients in the DOPPS

OBJECTIVE

To identify modifiable factors associated with health-related quality of life (HRQOL) among chronic hemodialysis patients.

METHODS

Analysis of baseline data of 9,526 hemodialysis patients from seven countries enrolled in phase I of the Dialysis Outcomes and Practice Patterns Study (DOPPS). Using the Kidney Disease Quality of Life Short Form (KDQOL-SF(TM)), we determined scores for 8 generic scale summaries derived from these scales, i.e., the physical component summary [PCS] and mental component summary [MCS], and 11 kidney disease- targeted scales. Regression models were used to adjust for differences in comorbidities and sociodemographic and treatment factors. The Benjamini-Hochberg procedure was used to correct P-values for multiple comparisons.

RESULTS

Unemployment and psychiatric disease were independently and significantly associated with lower scores for all generic and several kidney disease-targeted HRQOL measures. Several other comorbidities, lower educational level, lower income, and hypoalbuminemia were also independently and significantly associated with lower scores of PCS and/or MCS and several generic and kidney disease-targeted scales. Hemodialysis by catheter was associated with significantly lower PCS scores, partially explained by the correlation with covariates.

CONCLUSION

Associations of poorer HRQOL with preventable or controllable factors support a greater focus on psychosocial and medical interventions to improve the well-being of hemodialysis patients.

Sexual dysfunction in dialysis patients treated with antihypertensive or antidepressive medications: results from the DOPPS

BACKGROUND

The relationship between medication prescription and sexual dysfunction (SD) in dialysis patients is unclear.

METHODS

We studied antihypertensive and antidepressive agents prescribed for 7346 patients in the Dialysis Outcomes and Practice Patterns Study phase 1 (DOPPS I) and 8891 patients in DOPPS II. At baseline, DOPPS I patients completed a quality of life survey, including four questions about sexual functioning, from which we created a composite SD scale. DOPPS II patients were asked only one question about SD. We examined predictors of SD with logistic regression, using numerous patient characteristics, comorbid conditions and additional variables.

RESULTS

Reported SD ranged from 66.4% (France) to 84.5% (Spain). The mean composite SD score ranged from 6.4 (Spain) to 7.9 (Germany) (on a 3-15 scale). Peripheral alpha-blockers increased odds of DOPPS I patients having their sex life bothered by end-stage renal disease (ESRD) (OR=1.18), and there were elevated odds of arousal problems with central antagonists, loop diuretics and peripheral alpha-blockers (OR=1.19, 1.24 and 1.29, respectively). Selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines increased odds of problems with enjoyment (OR=1.59 and 1.26, respectively) and arousal (OR=1.70 and 1.24, respectively), and having sex life bothered by ESRD (DOPPS I: OR=1.36 and 1.24; DOPPS II: 1.30 and 1.31, respectively). Vasodilators reduced the odds of sexual enjoyment problems (OR=0.75). Composite SD scores worsened with peripheral alpha-blockers (+0.41), tricyclics (+0.78), SSRIs (+0.80) and benzodiazepines (+0.50), but not with vasodilators (-0.57).

CONCLUSIONS

Awareness of associations between SD and prescribed medications may offer opportunities for intervention.

Mineral metabolism and mortality in patients with chronic kidney disease

Chronic kidney disease is associated with profound alterations in mineral metabolism. A growing body of evidence, based largely on observational studies, indicates that patient mortality is associated with altered mineral metabolism. Evidence is reviewed concerning the association between mortality and high concentrations of serum phosphorus, calcium, calcium-phosphate product, and parathyroid hormone. In addition, mortality may be independently associated with dialysate calcium concentration, type of phosphate binder therapy, and use of vitamin D analogs. Practices related to management of altered mineral metabolism may prove to be a promising means of improving outcomes for patients with chronic kidney disease.

Pruritus in haemodialysis patients: International results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Pruritus affects many haemodialysis (HD) patients. In this study, pruritus and its relationship to morbidity, mortality, quality of life (QoL), sleep quality and patient laboratory measures were analysed in >300 dialysis units in 12 countries.

METHODS

Pruritus data were collected from 18 801 HD patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) (1996-2004). Analyses were adjusted for age, gender, black race, Kt/V, haemoglobin, serum albumin, albumin-corrected serum calcium, serum phosphorus, 13 comorbidities, depression, years on dialysis, country and facility clustering effects.

RESULTS

Moderate to extreme pruritus was experienced by 42% of prevalent HD patients in DOPPS during 2002/2003. Many patient characteristics were significantly associated with pruritus, but this did not explain the large differences in pruritus between countries (ranging from 36% in France to 50% in the UK) and between facilities (5-75%). Pruritus was slightly less common in patients starting HD than in patients on dialysis >3 months. Pruritus in new end-stage renal disease (ESRD) patients likely results from pre-existing conditions and not haemodialysis per se, indicating the need to understand development of pruritus before ESRD. Patients with moderate to extreme pruritus were more likely to feel drained [adjusted odds ratio (AOR) = 2.3-5.2, P < 0.0001] and to have poor sleep quality (AOR = 1.9-4.1, P < or = 0.0002), physician-diagnosed depression (AOR = 1.3-1.7, P < or = 0.004), and QoL mental and physical composite scores 3.1-8.6 points lower (P < 0.0001) than patients with no/mild pruritus. Pruritus in HD patients was associated with a 17% higher mortality risk (P < 0.0001), which was no longer significant after adjusting for sleep quality measures.

CONCLUSIONS

The pruritus/mortality relationship may be substantially attributed to poor sleep quality. The many poor outcomes associated with pruritus underscore the need for better therapeutic agents to provide relief for the 40-50% of HD patients affected by pruritus.

Incidence and risk factors for hip or other bone fractures among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

The available data on bone fractures in hemodialysis (HD) patients are limited to results of a few studies of subgroups of patients in the United States. This study describes the prevalence of hip fractures and the incidence and risk factors associated with hip and other fractures in representative groups of HD facilities (n=320) and patients (n=12 782) from the 12 countries in the second phase of the Dialysis Outcomes and Practice Patterns Study (2002-2004). Among prevalent patients, 2.6% had a prior hip fracture. The incidence of fractures was 8.9 per 1000 patient years for new hip fractures and 25.6 per 1000 for any new fracture. Older age (relative risk (RR)(HIP)=1.91, RR(ANY)=1.33, P<0.0001), female sex (RR(HIP)=1.41, P=0.02; RR(ANY)=1.59, P<0.0001), prior kidney transplant (RR(HIP)=2.35, P=0.04; RR(ANY)=1.76, P=0.007), and low serum albumin (RR(HIP)=1.85, RR(ANY)=1.45, per 1 g/dl lower, P<0.0001) were predictive of new fractures. Elevated risk of new hip fracture was observed for selective serotonin reuptake inhibitors and combination narcotic medications (RR=1.63, RR=1.74, respectively, P<0.05). Several medications were associated with risk of any new fracture: narcotic pain medications (RR=1.67, P=0.02), benzodiazepines (RR=1.31, P=0.03), adrenal cortical steroids (RR=1.40, P<0.05), and combination narcotic medications (RR=1.72, P=0.001). Parathyroid hormone (PTH) levels >900 pg/ml were associated with an elevated risk of any new fracture (RR=1.72, P<0.05) versus PTH 150-300. The results suggest that greater selectivity in prescribing several classes of psychoactive drugs and more efficient treatment of secondary hyperparathyroidism may help reduce the burden of fractures in HD patients.

Starting and withdrawing haemodialysis--associations between nephrologists' opinions, patient characteristics and practice patterns (data from the Dialysis Outcomes and Practice Patterns Study)

BACKGROUND

The incidence and prevalence of haemodialysis vary widely across countries. The variation may be attributable to differences in the incidence of end-stage renal disease and/or in the availability of haemodialysis. Previous studies have identified differences in nephrologists' opinions about the availability of haemodialysis and its appropriateness for patients with comorbidities. We studied the associations between nephrologists' opinions, availability of haemodialysis, patient characteristics and comorbidities, and facilities' withdrawal rates.

METHODS

Most of our analyses used data from 242 haemodialysis units in six countries (France, Germany, Italy, Spain, UK and the USA) in the first phase of the Dialysis Outcomes and Practice Patterns Study (DOPPS I). Opinions about access to and practice patterns in dialysis facilities, measured by the level of agreement with standardized statements, were collected from medical directors and nurse managers. A sub-analysis considered data from corresponding facilities in DOPPS II.

RESULTS

We found wide variations in the prevalence of waiting lists for new dialysis patients (UK 60%; USA 25%; Germany 0%; P < 0.05), in agreement with starting haemodialysis for patients with advanced age, dementia and comorbidities (UK, France < USA < other countries; P < 0.05), and in agreement with withdrawing dialysis (other countries < UK/USA; P < 0.05). The estimated glomerular filtration rate at the start of dialysis was not significantly different in units with waiting lists. Significant associations were found between nephrologists' opinions and the odds of patients being > or =80 years old, and between opinions and the rate and relative risk of withdrawal of haemodialysis. No significant associations were found between opinions and patients' comorbidities or dependency.

CONCLUSION

Differences within and across countries in nephrologists' opinions regarding starting and withdrawing haemodialysis reflect differences in access to haemodialysis and the practice of withdrawal of haemodialysis in their facilities.

Large variations in prescriptions of gastrointestinal medications in hemodialysis patients on three continents: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Little is known about proton pump inhibitor (PPI) or H(2) receptor antagonist (HA) prescription patterns or regarding use of predictors in hemodialysis patients. Proton pump inhibitor and HA prescribing patterns were investigated in 8628 hemodialysis patients from seven countries enrolled in the prospective, observational Dialysis Outcomes and Practice Patterns Study. Logistic regression examined predictors associated with PPI and HA use, adjusting for age, sex, country, time with end-stage renal disease, medications, 14 comorbid conditions, and the association between the number of comorbid conditions and the prescription of gastrointestinal (GI) medications. In a cross-section from February 1, 2000, 3.4% to 36.9% of patients received an HA and 0.8% to 26.9% took a PPI, depending upon the country. From 1996 to 2001, the prescription of HAs declined while PPI use increased. Facility use of HAs and PPIs ranged from 0% to 94% of patients. H2 receptor antagonist or PPI use was significantly and independently associated with age, narcotic use, corticosteroids, acetaminophen, nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, selective serotonin reuptake inhibitors, coronary artery disease history, cardiovascular diseases other than hypertension or congestive heart failure, peripheral vascular disease, pulmonary disease, and GI bleed. Proton pump inhibitors or HAs were more likely to be prescribed in Italy, Spain, and the United Kingdom than in the United States. The odds of PPI prescription increased if serum phosphorus <5.5 mEq/L or serum albumin <3.5 g/dL. Prescription of GI medications was associated with many comorbidities and use of several medications. Extreme variability of prescription patterns suggests that there is no standard approach in treatment practices.

Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS

Longer treatment time (TT) and slower ultrafiltration rate (UFR) are considered advantageous for hemodialysis (HD) patients. The study included 22,000 HD patients from seven countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Logistic regression was used to study predictors of TT > 240 min and UFR > 10 ml/h/kg bodyweight. Cox regression was used for survival analyses. Statistical adjustments were made for patient demographics, comorbidities, dose of dialysis (Kt/V), and body size. Europe and Japan had significantly longer (P < 0.0001) average TT than the US (232 and 244 min vs 211 in DOPPS I; 235 and 240 min vs 221 in DOPPS II). Kt/V increased concomitantly with TT in all three regions with the largest absolute difference observed in Japan. TT > 240 min was independently associated with significantly lower relative risk (RR) of mortality (RR = 0.81; P = 0.0005). Every 30 min longer on HD was associated with a 7% lower RR of mortality (RR = 0.93; P < 0.0001). The RR reduction with longer TT was greatest in Japan. A synergistic interaction occurred between Kt/V and TT (P = 0.007) toward mortality reduction. UFR > 10 ml/h/kg was associated with higher odds of intradialytic hypotension (odds ratio = 1.30; P = 0.045) and a higher risk of mortality (RR = 1.09; P = 0.02). Longer TT and higher Kt/V were independently as well as synergistically associated with lower mortality. Rapid UFR during HD was also associated with higher mortality risk. These results warrant a randomized clinical trial of longer dialysis sessions in thrice-weekly HD.

Improving outcomes for dialysis patients in the international Dialysis Outcomes and Practice Patterns Study

The international Dialysis Outcomes and Practice Patterns Study (DOPPS) is well suited to evaluate levels of deviation from emerging and established guidelines to clinical practice of hemodialysis, over time and by country. The DOPPS can also evaluate whether the target levels that are chosen in the guidelines are in agreement with outcomes such as elevated risk for mortality, hospitalization, and vascular access failure. At a special DOPPS symposium during the 2004 congress of the American Society of Nephrology, the authors presented such findings; key points from that symposium are presented in this article, focusing on vascular access, mineral metabolism, dialysis dose, and anemia management. Although an observational study cannot prove causality, DOPPS suggests large opportunities to improve care and outcomes of dialysis patients. The international perspective of DOPPS assists in the new efforts for international guidelines. Some encouraging trends in recent years are documented in these areas.

Factors associated with "do not resuscitate" orders and rates of withdrawal from hemodialysis in the international DOPPS

BACKGROUND

Worldwide statistics on practice patterns regarding "do not resuscitate" (DNR) orders and patient withdrawal from hemodialysis have not been uniformly collected or analyzed.

METHODS

Using data concerning adult hemodialysis patients randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States participating in the Dialysis Outcomes and Practice Patterns Study, DNR orders were tabulated at study entry from a prevalent cross-section of patients (N = 8615), using multivariate logistic regression to investigate characteristics associated with DNR status, Cox models to identify risk factors for withdrawal from hemodialysis, and scores from the mental component summary (MCS) and physical component summary (PCS) of the SF-36 to assess health-related quality of life.

RESULTS

The United States had the highest prevalence of DNR orders (7.5%) and rate of withdrawal from hemodialysis (3.5 per 100 patient-years). Significant and independent associations with higher odds ratio (OR) of DNR were observed for older age (OR 1.16 per 10 years higher, P = 0.03) and nursing home residence (OR 2.34, P = 0.003), and with higher relative risk (RR) of withdrawal from dialysis (RR 2.38, P < 0.001). Patients who withdrew from hemodialysis died within a mean of 7.8 days and a median of 6.0 days.

CONCLUSION

The higher prevalence of DNR and rate of withdrawal from hemodialysis in the United States are consistent with its greater legal and cultural emphasis on patient autonomy. By showing characteristics associated with these outcomes, this study contributes to our understanding of why hemodialysis patients request DNR or withdraw from treatment.

CKD Progression and Mortality Among Older Patients With Diabetes

BACKGROUND

Chronic kidney disease (CKD) is clearly associated with an increased risk for adverse outcomes; however, the cumulative impact of renal and cardiac complications in high-risk populations is not known. In addition, little is known about patterns of nephrology care in patients with CKD.

METHODS

We conducted a retrospective longitudinal cohort study assessing CKD prevalence and progression, associations with all-cause mortality, and variations in patterns of nephrology consultation in older patients with diabetes in a vertically integrated health care system.

RESULTS

A total of 12,570 patients within a 7-Veterans Affairs hospital service network in 1998 to 1999 were identified by means of computerized records. Nearly half (48%) were affected with CKD; most had mild to moderate CKD. After an observation period of 3 years, mortality rates in those unaffected with CKD were high (4.7 deaths/100 person-years) and increased substantially with progressive CKD (eg, 20.1 deaths/100 person-years with an estimated glomerular filtration rate [GFR] of 15 to 29 mL/min/1.73 m2 [0.25 to 0.48 mL/s/1.73 m2]). Only 7.2% of patients with CKD had a nephrology visit during the entire 5-year study period. Although visits increased with more advanced CKD, only 32% of patients with an estimated GFR of 15 to 29 mL/min/1.73 m2 had been seen in a nephrology clinic. We also found that nephrology referrals were driven preferentially by elevations in serum creatinine levels, rather than low GFRs.

CONCLUSION

Many in this cohort of older patients with diabetes are affected with CKD. Mortality rates are high, and mortality risks associated with CKD amplify those of other risk factors. Nephrology visits are low and may represent an unexploited resource for improving CKD management. Underrecognition of CKD likely is related to overestimation of kidney function by relying on serum creatinine level in elderly patients.

Predictors and consequences of altered mineral metabolism: the Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Altered mineral metabolism contributes to bone disease, cardiovascular disease, and other clinical problems in patients with end-stage renal disease.

METHODS

This study describes the recent status, significant predictors, and potential consequences of abnormal mineral metabolism in representative groups of hemodialysis facilities (N= 307) and patients (N= 17,236) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in the United States, Europe, and Japan from 1996 to 2001.

RESULTS

Many patients fell out of the recommended guideline range for serum concentrations of phosphorus (8% of patients below lower target range, 52% of patients above upper target range), albumin-corrected calcium (9% below, 50% above), calcium-phosphorus product (44% above), and intact PTH (51% below, 27% above). All-cause mortality was significantly and independently associated with serum concentrations of phosphorus (RR 1.04 per 1 mg/dL, P= 0.0003), calcium (RR 1.10 per 1 mg/dL, P < 0.0001), calcium-phosphorus product (RR 1.02 per 5 mg(2)/dL(2), P= 0.0001), PTH (1.01 per 100 pg/dL, P= 0.04), and dialysate calcium (RR 1.13 per 1 mEq/L, P= 0.01). Cardiovascular mortality was significantly associated with the serum concentrations of phosphorus (RR 1.09, P < 0.0001), calcium (RR 1.14, P < 0.0001), calcium-phosphorus product (RR 1.05, P < 0.0001), and PTH (RR 1.02, P= 0.03). The adjusted rate of parathyroidectomy varied 4-fold across the DOPPS countries, and was significantly associated with baseline concentrations of phosphorus (RR 1.17, P < 0.0001), calcium (RR 1.58, P < 0.0001), calcium-phosphorus product (RR 1.11, P < 0.0001), PTH (RR 1.07, P < 0.0001), and dialysate calcium concentration (RR 0.57, P= 0.03). Overall, 52% of patients received some form of vitamin D therapy, with parenteral forms almost exclusively restricted to the United States. Vitamin D was potentially underused in up to 34% of patients with high PTH, and overused in up to 46% of patients with low PTH. Phosphorus binders (mostly calcium salts during the study period) were used by 81% of patients, with potential overuse in up to 77% patients with low serum phosphorus concentration, and potential underuse in up to 18% of patients with a high serum phosphorus concentration.

CONCLUSION

This study expands our understanding of the relationship between altered mineral metabolism and outcomes and identifies several potential opportunities for improved practice in this area.

Association of predialysis serum bicarbonate levels with risk of mortality and hospitalization in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Experimental and some clinical data suggest that metabolic acidosis contributes to poor nutritional status, a strong predictor for mortality in hemodialysis patients. However, recent cross-sectional studies indicate that severe predialysis metabolic acidosis is associated with a greater normalized protein catabolic rate (nPCR) and greater serum albumin levels. Given this controversy, we analyzed data from the Dialysis Outcomes and Practice Pattern Study (DOPPS) for associations between predialysis serum bicarbonate and albumin concentrations, nPCR, and patient risk for mortality and hospitalization.

METHODS

Data from more than 7,000 representative and randomly selected hemodialysis DOPPS patients from France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States were analyzed. Serum bicarbonate (total CO2 ) levels predialysis were corrected to the midweek interdialytic interval.

RESULTS

The midweek predialysis serum bicarbonate level averaged 21.9 mEq/L (mmol/L) and correlated inversely with nPCR, serum albumin, and serum phosphorus values. Before and after adjusting for 15 comorbidities, nutrition, and equilibrated Kt/V, a U-curve best represented the association between predialysis serum bicarbonate level and risk for mortality or hospitalization. Patients with midweek predialysis serum bicarbonate levels of 20.1 to 21.0 mEq/L (mmol/L) faced the lowest risk for mortality, whereas those with bicarbonate levels of 21.1 to 22.0 mEq/L faced the lowest risk for hospitalization. Both high (>27 mEq/L) and low (< or =17 mEq/L) serum bicarbonate levels were associated with increased risk for mortality and hospitalization.

CONCLUSION

Moderate predialysis acidosis seems to be associated with better nutritional status and lower relative risk for mortality or hospitalization than is observed in patients with normal ranges of midweek predialysis serum bicarbonate concentration (approximately 24 mEq/L) or severe acidosis (<16 mEq/L).

Mineral metabolism and haemoglobin concentration among haemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Bone and mineral metabolism is abnormal in most chronic haemodialysis patients and is associated with a high mortality risk. Because of possible pathogenic links between anaemia and intact parathyroid hormone (iPTH), the present study evaluated associations of mineral metabolism indicators with haemoglobin (Hb).

METHODS

Data were collected from 317 facilities (12 089 haemodialysis patients) in Australia, Belgium, Canada, France, Germany, Italy, Japan, New Zealand, Spain, Sweden, the United Kingdom and the United States by the Dialysis Outcomes and Practice Patterns Study (DOPPS). The major outcome studied was probability of haemodialysis patients having a target Hb, per guidelines, of >/=11 g/dl at baseline. Major predictor variables were patient characteristics and laboratory markers of mineral metabolism: albumin-corrected serum calcium (calcium(Alb)), serum phosphorus (PO(4)) and iPTH. Analyses were adjusted for demographics, 15 comorbidity classes, baseline laboratory values, body mass index, years on dialysis, erythropoietin dose, vitamin D and catheter use, cause of end-stage renal disease and country.

RESULTS

The adjusted odds ratio (AOR) of having Hb >/=11 g/dl was significantly higher (P<0.0001) in patients with higher calcium(Alb) (AOR = 1.32 per 1 mg/dl), higher PO(4) (AOR = 1.08 per 1 mg/dl) and lower iPTH (AOR = 0.96 per 100 pg/ml). Furthermore, 4 month intrapatient changes in Hb concentration were significantly (P<0.0001) related to 4 month changes in calcium(Alb) (0.17 g/dl Hb rise per 1 mg/dl higher calcium(Alb)) and PO(4) (0.11 g/dl Hb rise per 1 mg/dl higher PO(4)). Mean weekly recombinant human erythropoietin (rHuEpo) doses were higher for patients with high PO(4) or iPTH levels, but lower for patients with calcium(Alb) >9.5 mg/dl, after patient mix and Hb concentration adjustments.

CONCLUSIONS

The results of this study indicate that higher serum calcium(Alb) and PO(4) levels are each independently associated with better anaemia control. This relationship is independent of vitamin D use, PTH levels and prescribed rHuEpo dose. Despite this benefit of better anaemia control at higher serum calcium(Alb) and PO(4) concentrations, lower calcium and PO(4) levels, as recommended by the K/DOQI guidelines, should still serve as the long-term goal for HD patients in order to minimize tissue calcification and mortality risk.

HMG-coenzyme a reductase inhibitor use is associated with mortality reduction in hemodialysis patients

BACKGROUND

Cardiovascular disease is the most common cause of mortality in patients with end-stage renal disease. Cardiovascular benefits of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been clearly established in the general population, but not in dialysis patients. This study examined statin prescription patterns and assessed the relationship between statin prescription and clinical outcomes in hemodialysis (HD) patients.

METHODS

Data were analyzed from the Dialysis Outcomes and Practice Patterns Study, a prospective observational study of HD patients randomly selected from representative dialysis facilities in France, Germany, Italy, Spain, the United Kingdom, Japan, and the United States. Predictors of statin prescription were investigated by means of logistic regression. Cox regression models tested the association between statin prescription and risk for mortality and cardiac events, with adjustments for common demographic factors and comorbid conditions.

RESULTS

Statins were prescribed for 11.8% of HD patients overall. Most facilities (81.2%) prescribed statins to less than 20% of their patients. Patients prescribed statins had a 31% lower relative risk for death compared with those not prescribed statins (P < 0.0001). Statins were associated with a 23% lower cardiac mortality risk (P = 0.03) and a 44% lower noncardiac mortality risk (P < 0.0001). At a facility level, prescribing statins was associated with lower overall mortality rate, with a 5% lower risk for every 10% increase in number of patients prescribed statins within the facility (P = 0.02).

CONCLUSION

Statin prescription is associated with reduced mortality in HD patients, providing additional support for the value of statin therapy in this patient group.

Patterns of hepatitis C prevalence and seroconversion in hemodialysis units from three continents: the DOPPS

BACKGROUND

Hepatitis C virus (HCV) remains a problem within hemodialysis units. This study measures HCV prevalence and seroconversion rates across seven countries and investigates associations with facility-level practice patterns.

METHODS

The study sample was from the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective, observational study of adult hemodialysis patients randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States. Logistic regression was used to model odds of HCV prevalence, and Cox regression was used to model time from study entry to HCV seroconversion.

RESULTS

Mean HCV facility prevalence was 13.5% and varied among countries from 2.6% to 22.9%. Increased HCV prevalence was associated with longer time on dialysis, male gender, black race, diabetes, hepatitis B (HBV) infection, prior renal transplant, and alcohol or substance abuse in the previous 12 months. Approximately half of the facilities (55.6%) had no seroconversions during the study period. HCV seroconversion was associated with longer time on dialysis, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), HBV infection, and recurrent cellulitis or gangrene. An increase in highly trained staff was associated with lower HCV prevalence (OR = 0.93 per 10% increase, P= 0.003) and risk of seroconversion (RR = 0.92, P= 0.07). Seroconversion was associated with an increase in facility HCV prevalence (RR = 1.36, P < 0.0001), but not with isolation of HCV-infected patients (RR = 1.01, P= 0.99).

CONCLUSION

There are differences in HCV prevalence and rate of seroconversion at the country and the hemodialysis facility level. The observed variation suggests opportunities for improved HCV outcomes.

Mortality among hemodialysis patients in Europe, Japan, and the United States: case-mix effects

BACKGROUND

The Dialysis Outcomes and Practice Patterns Study is well suited to identify case-mix effects, given its extensive data set. The data set was used to examine the influence of case-mix variables on mortality and the extent to which these variables account for differences in mortality across regions, as well as the prevalence and incidence of hepatitis B and hepatitis C.

METHODS

Demographic and comorbid disease features were determined for 8,615 patients internationally; mortality was recorded for this cohort, plus replacement patients (total n = 16,720), from 1996 to 2002. Mortality was associated with increasing age, nonblack race, coronary artery disease, congestive heart failure, other cardiac disease, diabetes mellitus, peripheral vascular disease, cerebrovascular disease, absence of hypertension, lung disease, cancer, human immunodeficiency virus infection, gastrointestinal bleeding, neurologic disease, psychiatric disease, cellulitis/gangrene, hepatitis C, and smoking.

RESULTS

US patients were slightly older than those in Europe or Japan and had the highest prevalence of diabetes, coronary artery disease, congestive heart failure, peripheral vascular disease, and cerebrovascular disease.

CONCLUSION

Upon adjusting for case-mix to assess mortality across facilities, it was found that regional differences in mortality (highest in the United States and lowest in Japan) and differences across facilities within nations remain after such corrections. It is likely that practice patterns account for some of this variation. Prevalence of hepatitis B virus (HBV) across facilities increased as the number of dialyzing patients per facility increased; risk of HBV seroconversion decreased among facilities using protocols for treatment of patients with HBV infection. Greater employment of staff with at least 2 years of formal nursing training was associated with lower prevalence of hepatitis C virus infection and lower seroconversion risk.

Mortality among hemodialysis patients in Europe, Japan, and the United States: case-mix effects

BACKGROUND

The Dialysis Outcomes and Practice Patterns Study is well suited to identify case-mix effects, given its extensive data set. The data set was used to examine the influence of case-mix variables on mortality and the extent to which these variables account for differences in mortality across regions, as well as the prevalence and incidence of hepatitis B and hepatitis C.

METHODS

Demographic and comorbid disease features were determined for 8,615 patients internationally; mortality was recorded for this cohort, plus replacement patients (total n = 16,720), from 1996 to 2002. Mortality was associated with increasing age, nonblack race, coronary artery disease, congestive heart failure, other cardiac disease, diabetes mellitus, peripheral vascular disease, cerebrovascular disease, absence of hypertension, lung disease, cancer, human immunodeficiency virus infection, gastrointestinal bleeding, neurologic disease, psychiatric disease, cellulitis/gangrene, hepatitis C, and smoking.

RESULTS

US patients were slightly older than those in Europe or Japan and had the highest prevalence of diabetes, coronary artery disease, congestive heart failure, peripheral vascular disease, and cerebrovascular disease.

CONCLUSION

Upon adjusting for case-mix to assess mortality across facilities, it was found that regional differences in mortality (highest in the United States and lowest in Japan) and differences across facilities within nations remain after such corrections. It is likely that practice patterns account for some of this variation. Prevalence of hepatitis B virus (HBV) across facilities increased as the number of dialyzing patients per facility increased; risk of HBV seroconversion decreased among facilities using protocols for treatment of patients with HBV infection. Greater employment of staff with at least 2 years of formal nursing training was associated with lower prevalence of hepatitis C virus infection and lower seroconversion risk.

Magnitude and impact of abnormal mineral metabolism in hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Mineral metabolism has emerged as an important predictor of morbidity and mortality in dialysis patients, independent of bone and muscle concerns. Several expert panels have issued management guidelines for mineral metabolism.

METHODS

The state of mineral metabolism (serum parathyroid hormone [PTH], phosphorus, calcium, and calcium-phosphorus product) was described for representative samples of patients and facilities from 7 countries (France, Germany, Italy, Japan, Spain, United Kingdom, and United States) participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS I, 1996-2001; DOPPS II, 2002-2004).

RESULTS

A relatively modest percentage of patients fell within the guideline range for PTH (21.4% in DOPPS I, 26.2% in DOPPS II), serum phosphorus (40.8%, 44.4%), albumin-corrected serum calcium (40.5%, 42.5%), and calcium-phosphorus product (56.6%, 61.4%). Results were not dramatically different across countries. The majority of patients not within guideline ranges had high serum levels of phosphorus (51.6% in DOPPS I, 46.7% in DOPPS II), calcium (50.1%, 48.6%), and calcium-phosphorus product (43.4%, 38.6%) and low (<150 pg/mL) concentrations of PTH (52.9%, 47.5%). It was rare for patients to fall within recommended ranges for all indicators of mineral metabolism; 23% to 28% fell within guideline for at least 3 measures and only 4.6% to 5.5% of patients were within range for all 4. The risks of all-cause and cardiovascular mortality were directly and independently associated with each of the 4 indicators.

CONCLUSION

The DOPPS provides a useful comparison benchmark for the state of mineral metabolism management of patients with kidney disease; it also affirms the association between mineral metabolism and important patient outcomes.

Screening for depression in hemodialysis patients: Associations with diagnosis, treatment, and outcomes in the DOPPS

BACKGROUND

Depressive symptoms and depression are the most frequent psychologic problems reported by hemodialysis patients. We assessed the prevalence of depressive symptoms and physician-diagnosed depression, their variations by country, and associations with treatment by antidepressants among hemodialysis patients. We also assessed whether depressive symptoms were independently associated with mortality, hospitalization, and dialysis withdrawal.

METHODS

The sample was represented by 9382 hemodialysis patients randomly selected from dialysis centers of 12 countries enrolled in the Dialysis Outcomes and Practice Patterns Study (DOPPS II). Depressive symptoms were assessed by the short version of the Center for Epidemiological Studies Depression Screening Index (CES-D), using > or =10 CES-D score as the cut-off value.

RESULTS

Overall prevalence of physician-diagnosed depression was 13.9%, and percentage of CES-D score > or =10 43.0%. While the smallest prevalence of physician-diagnosed depression was observed in Japan (2.0%) and France (10.6%), the percentage of CES-D score > or =10 in these counties was similar to the whole sample. Patients on antidepressants also varied by country, 34.9% and 17.3% among those with physician-diagnosed depression and CES-D scores > or =10, respectively. In Cox models adjusted for several comorbidities, CES-D scores > or =10 were associated with significantly higher relative risks (RR) of death (RR = 1.42; 95% CI = 1.29 to 1.57), hospitalization (RR = 1.12; 95% CI = 1.03 to 1.22), and dialysis withdrawal (RR = 1.55; 95% CI = 1.29 to 1.85).

CONCLUSION

The data suggest that depression is underdiagnosed and undertreated among hemodialysis patients. CES-D can help identify hemodialysis patients who are at higher risk of death and hospitalization. Interventions should target these patients with the goal to improve survival and reduce hospitalizations.