County-level air quality and the prevalence of diagnosed chronic kidney disease in the US Medicare population.

BACKGROUND: Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution. METHODS: Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter ≤2.5 µm (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5 concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status. RESULTS: Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5 concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02-1.05; p<0.001) for an increase of 4 µg/m3 in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5 levels ≥14 µg/m3 (highest quartile: PR = 1.05, 95% CI: 1.03-1.07), which is consistent with current ambient air quality standard of 12 µg/m3, but much lower than the level typically considered healthy for sensitive groups (~40 µg/m3). CONCLUSION: A positive association was observed between county-level PM2.5 concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.

Older Patients' Perspectives on Managing Complexity in CKD Self-Management.

BACKGROUND AND OBJECTIVES: Patients with CKD are asked to perform self-management tasks including dietary changes, adhering to medications, avoiding nephrotoxic drugs, and self-monitoring hypertension and diabetes. Given the effect of aging on functional capacity, self-management may be especially challenging for older patients. However, little is known about the specific challenges older adults face maintaining CKD self-management regimens. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted an exploratory qualitative study designed to understand the relationship among factors facilitating or impeding CKD self-management in older adults. Six focus groups (n=30) were held in August and September of 2014 with veterans≥70 years old with moderate-to-severe CKD receiving nephrology care at the Atlanta Veterans Affairs Medical Center. Grounded theory with a constant comparative method was used to collect, code, and analyze data. RESULTS: Participants had a mean age (range) of 75.1 (70.1-90.7) years, 60% were black, and 96.7% were men. The central organizing concept that emerged from these data were managing complexity. Participants typically did not have just one chronic condition, CKD, but a number of commonly co-occurring conditions. Recommendations for CKD self-management therefore occurred within a complex regimen of recommendations for managing other diseases. Participants identified overtly discordant treatment recommendations across chronic conditions (e.g., arthritis and CKD). Prioritization emerged as one effective strategy for managing complexity (e.g., focusing on BP control). Some patients arrived at the conclusion that they could group concordant recommendations to simplify their regimens (e.g., protein restriction for both gout and CKD). CONCLUSIONS: Among older veterans with moderate-to-severe CKD, multimorbidity presents a major challenge for CKD self-management. Because virtually all older adults with CKD have multimorbidity, an integrated treatment approach that supports self-management across commonly occurring conditions may be necessary to meet the needs of these patients.

A Randomized Trial to Reduce Disparities in Referral for Transplant Evaluation.

Georgia has the lowest kidney transplant rates in the United States and substantial racial disparities in transplantation. We determined the effectiveness of a multicomponent intervention to increase referral of patients on dialysis for transplant evaluation in the Reducing Disparities in Access to kidNey Transplantation Community Study (RaDIANT), a randomized, dialysis facility-based, controlled trial involving >9000 patients receiving dialysis from 134 dialysis facilities in Georgia. In December of 2013, we selected dialysis facilities with either low transplant referral or racial disparity in referral. The intervention consisted of transplant education and engagement activities targeting dialysis facility leadership, staff, and patients conducted from January to December of 2014. We examined the proportion of patients with prevalent ESRD in each facility referred for transplant within 1 year as the primary outcome, and disparity in the referral of black and white patients as a secondary outcome. Compared with control facilities, intervention facilities referred a higher proportion of patients for transplant at 12 months (adjusted mean difference [aMD], 7.3%; 95% confidence interval [95% CI], 5.5% to 9.2%; odds ratio, 1.75; 95% CI, 1.36 to 2.26). The difference between intervention and control facilities in the proportion of patients referred for transplant was higher among black patients (aMD, 6.4%; 95% CI, 4.3% to 8.6%) than white patients (aMD, 3.7%; 95% CI, 1.6% to 5.9%; P<0.05). In conclusion, this intervention increased referral and improved equity in kidney transplant referral for patients on dialysis in Georgia; long-term follow-up is needed to determine whether these effects led to more transplants.

ESRD Databases, Public Policy, and Quality of Care: Translational Medicine and Nephrology.

Efforts to improve care of patients with ESRD and the policies that guide those activities depend on evidence-based best practices derived from clinical trials and carefully conducted observational studies. Our review describes this process in the context of the translational research model (bench to bedside to populations), with a particular emphasis on bedside care. We illustrate some of its accomplishments and describe the limitations of the data and evidence supporting policy and practice.

Association of Reduced eGFR and Albuminuria with Serious Fall Injuries among Older Adults.

BACKGROUND AND OBJECTIVES: Falls are common and associated with adverse outcomes in patients on dialysis. Limited data are available in earlier stages of CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We analyzed data from 8744 Reasons for Geographic and Racial Differences in Stroke Study participants ≥65 years old with Medicare fee for service coverage. Serious fall injuries were defined as a fall-related fracture, brain injury, or joint dislocation using Medicare claims. Hazard ratios (HRs) for serious fall injuries were calculated by eGFR and albumin-to-creatinine ratio (ACR). Among 2590 participants with CKD (eGFR<60 ml/min per 1.73 m(2) or ACR≥30 mg/g), cumulative mortality after a serious fall injury compared with age-matched controls without a fall injury was calculated. RESULTS: Overall, 1103 (12.6%) participants had a serious fall injury over 9.9 years of follow-up. The incidence rates per 1000 person-years of serious fall injuries were 21.7 (95% confidence interval [95% CI], 20.3 to 23.2), 26.6 (95% CI, 22.6 to 31.3), and 38.3 (95% CI, 31.2 to 47.0) at eGFR levels ≥60, 45-59, and <45 ml/min per 1.73 m(2), respectively, and 21.3 (95% CI, 20.0 to 22.8), 31.7 (95% CI, 27.5 to 36.5), and 42.2 (95% CI, 31.3 to 56.9) at ACR levels <30, 30-299, and ≥300 mg/g, respectively. Multivariable adjusted HRs for serious fall injuries were 0.91 (95% CI, 0.76 to 1.09) and 1.09 (95% CI, 0.86 to 1.37) for eGFR=45-59 and <45 ml/min per 1.73 m(2), respectively, versus eGFR≥60 ml/min per 1.73 m(2) and 1.31 (95% CI, 1.11 to 1.54) and 1.81 (95% CI, 1.30 to 2.50) for ACR=30-299 and ≥300 mg/g, respectively, versus ACR<30 mg/g. Among participants with CKD, cumulative 1-year mortality rates among patients with a serious fall and age-matched controls were 21.0% and 5.5%, respectively. CONCLUSIONS: Elevated ACR but not lower eGFR was associated with serious fall injuries. Evaluation for fall risk factors and fall prevention strategies should be considered for older adults with elevated ACR.

Racial and Ethnic Disparities in Graft and Recipient Survival in Elderly Kidney Transplant Recipients.

OBJECTIVES: To investigate racial and ethnic differences in graft and recipient survival in elderly kidney transplant recipients. DESIGN: Retrospective cohort. SETTING: First-time, kidney-only transplant recipients aged 60 and older of age at transplantation transplanted between July 1996 and October 2010 (N = 44,013). PARTICIPANTS: United Network for Organ Sharing (UNOS) database. MEASUREMENTS: Time to graft failure and death obtained from the UNOS database and linkage to the Social Security Death Index. Neighborhood poverty from 2000 U.S. Census geographic data. RESULTS: Of the 44,013 recipients in the sample, 20% were black, 63% non-Hispanic white, 11% Hispanic, 5% Asian, and the rest "other racial groups." In adjusted Cox models, blacks were more likely than whites to experience graft failure (hazard ratio (HR) = 1.23, 95% confidence interval (CI) = 1.15-1.32), whereas Hispanics (HR = 0.77, 95% CI = 0.70-0.85) and Asians (HR = 0.70, 95% CI = 0.61-0.81) were less likely to experience graft failure. Blacks (HR = 0.84, 95% CI = 0.80-0.88), Hispanics (HR = 0.68, 95% CI = 0.64-0.72), and Asians (HR = 0.62, 95% CI = 0.57-0.68) were less likely than whites to die after renal transplantation. CONCLUSION: Elderly blacks are at greater risk of graft failure than white transplant recipients but survive longer after transplantation. Asians have the highest recipient and graft survival, followed by Hispanics. Further studies are needed to assess additional factors affecting graft and recipient survival in elderly adults and to investigate outcomes such as quality of life.

Sociodemographic and geographic predictors of quality of care in United States patients with end-stage renal disease due to lupus nephritis.

OBJECTIVE: To describe end-stage renal disease (ESRD) quality of care (receipt of pre-ESRD nephrology care, access to kidney transplantation, and placement of permanent vascular access for dialysis) in US patients with ESRD due to lupus nephritis (LN-ESRD) and to examine whether quality measures differ by patient sociodemographic characteristics or US region. METHODS: National surveillance data on patients in the US in whom treatment for LN-ESRD was initiated between July 2005 and September 2011 (n = 6,594) were analyzed. Odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (95% CIs) were determined for each quality measure, according to sociodemographic factors and US region. RESULTS: Overall, 71% of the patients received nephrology care prior to ESRD. Black and Hispanic patients were less likely than white patients to receive pre-ESRD care (OR 0.73 [95% CI 0.63-0.85] and OR 0.73 [95% CI 0.60-0.88], respectively) and to be placed on the kidney transplant waitlist within the first year after the start of ESRD (HR 0.78 [95% CI 0.68-0.91] and HR 0.82 [95% CI 0.68-0.98], respectively). Those with Medicaid (HR 0.51 [95% CI 0.44-0.58]) or no insurance (HR 0.36 [95% CI 0.29-0.44]) were less likely than those with private insurance to be placed on the waitlist. Only 24% had a permanent vascular access, and placement was even less likely among the uninsured (OR 0.62 [95% CI 0.49-0.79]). ESRD quality-of-care measures varied 2-3-fold across regions of the US, with patients in the Northeast and Northwest generally having higher probabilities of adequate care. CONCLUSION: LN-ESRD patients have suboptimal ESRD care, particularly with regard to placement of dialysis vascular access. Minority race/ethnicity and lack of private insurance are associated with inadequate ESRD care. Further studies are warranted to examine multilevel barriers to, and develop targeted interventions to improve delivery of, care among patients with LN-ESRD.

Racial and ethnic disparities in pediatric renal allograft survival in the United States.

This study was undertaken to describe the association of patient race/ethnicity and renal allograft survival among the national cohort of pediatric renal allograft recipients. Additionally, we determined whether racial and ethnic differences in graft survival exist among individuals living in low- or high-poverty neighborhoods and those with private or public insurance. Among 6216 incident, pediatric end-stage renal disease patients in the United States Renal Data System (kidney transplant from 2000 through September, 2011), 14.4% experienced graft failure, with a median follow-up time of 4.5 years. After controlling for multiple covariates, black race, but not Hispanic ethnicity, was significantly associated with a higher rate of graft failure for both deceased and living donor transplant recipients. Disparities were particularly stark by 5 years post transplant, when black living donor transplant recipients experienced only 63.0% graft survival compared with 82.8 and 80.8% for Hispanics and whites, respectively. These disparities persisted among high- and low-poverty neighborhoods and among both privately and publicly insured patients. Notably profound declines in both deceased and living donor graft survival rates for black, compared with white and Hispanic, children preceded the 3-year mark when transplant Medicare eligibility ends. Further research is needed to identify the unique barriers to long-term graft success among black pediatric transplant recipients.

Validation study of medicare claims to identify older US adults with CKD using the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

BACKGROUND: Health care claims data may provide a cost-efficient approach for studying chronic kidney disease (CKD). STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: We compared characteristics and outcomes for individuals with CKD defined using laboratory measurements versus claims data from 6,982 REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study participants who had Medicare fee-for-service coverage. PREDICTORS: Presence of CKD as defined by both the REGARDS Study (CKDREGARDS) and Medicare data (CKDMedicare), presence of CKDREGARDS but not CKDMedicare, and presence of CKDMedicare but not CKDREGARDS, and absence of both CKDREGARDS and CKDMedicare. OUTCOMES: Mortality and incident end-stage renal disease (ESRD). MEASUREMENTS: The research study definition of CKD (CKDREGARDS) included estimated glomerular filtration rate (eGFR) < 60mL/min/1.73m(2) or albumin-creatinine ratio > 30mg/g at the REGARDS Study visit. CKD in Medicare (CKDMedicare) was identified during the 2 years before each participant's REGARDS visit using a claims-based algorithm. RESULTS: Overall, 32% of participants had CKDREGARDS and 6% had CKDMedicare. Sensitivity, specificity, and positive and negative predictive values of CKDMedicare for identifying CKDREGARDS were 15.5% (95% CI, 14.0%-17.1%), 97.7% (95% CI, 97.2%-98.1%), 75.6% (95% CI, 71.4%-79.5%), and 71.5% (95% CI, 70.4%-72.6%), respectively. Mortality and ESRD incidence rates, expressed per 1,000 person-years, were higher for participants with versus without CKDMedicare (mortality: 72.5 [95% CI, 61.3-83.7] vs 33.3 [95% CI, 31.5-35.2]; ESRD: 16.4 [95% CI, 11.2-21.6] vs 1.3 [95% CI, 0.9-1.6]) and with versus without CKDREGARDS (mortality: 59.9 [95% CI, 55.4-64.4] vs 25.5 [95% CI, 23.6-27.4]; ESRD: 6.8 [95% CI, 5.4-8.3] vs 0.1 [95% CI, 0.0-0.3]). Among participants with CKDREGARDS, those with abdominal obesity, diabetes, anemia, lower eGFR, more outpatient visits, hospitalization, and a nephrologist visit in the 2 years before their REGARDS visit were more likely to have CKDMedicare. LIMITATIONS: CKDREGARDS relied on eGFR and albuminuria assessed at a single visit. CONCLUSIONS: CKD, whether defined in claims or through research study measurements, was associated with increased mortality and ESRD. However, individuals with CKD identified in claims may represent a select high-risk population.

The association between race and income on risk of mortality in patients with moderate chronic kidney disease.

BACKGROUND: Socioeconomic status (SES) is independently associated with chronic kidney disease (CKD) progression; however, its association with other CKD outcomes is unclear. In particular, the potential differential effect of SES on mortality among blacks and whites is understudied in CKD. We aimed to examine survival among individuals with prevalent CKD by income and race in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. METHODS: We examined 2,761 participants with prevalent CKD stage 3 or 4 between 2003 and 2007 in the REGARDS cohort. Participants were followed through March 2013. Mortality from any cause was assessed by income and race (black or white). Low income was defined as an annual household income < $20,000, and was compared to higher incomes (≥$20,000). Cox proportional hazards models adjusted for age, gender, education, insurance, CKD stage, comorbidity and county-level poverty were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). RESULTS: A total of 750 deaths (27.5%) occurred during the follow-up period. Average follow-up time was 6.6 years among those alive and 3.7 years among those who died. Low income participants had an elevated adjusted hazard of mortality (HR = 1.58, 95% CI 1.24-2.00) compared to higher income participants. Low income was associated with all-cause mortality regardless of race (HR 1.53; 95% CI 1.18-1.99 among blacks and HR 1.38; 95% CI 1.10-1.74 among whites), with no significant statistical interaction between household income and race (p-value = 0.634). However, black participants had a higher adjusted hazard of mortality (HR = 1.30, 95% CI 1.02-1.65) compared to whites, which was independent of income. CONCLUSION: Income was associated with increased mortality for both blacks and whites with CKD. Blacks with CKD had higher mortality than whites even after adjusting for important socio-demographic and clinical factors.

Kidney transplantation and the intensity of poverty in the contiguous United States.

BACKGROUND: Geographic variation in kidney transplantation rates in the United States has been described previously but remains unexplained by age, race, sex, or socioeconomic status differences. Geographic variations in the concentration of poverty appear to impact end-stage renal disease care and potentially access to transplantation. METHODS: We studied the impact of how spatial topography of poverty across geographical regions in the contiguous United States is associated with kidney transplantation in the 48 contiguous U.S. states. RESULTS: We found considerable geographic variation in transplantation rates across the country that persisted across quartiles of county-level median household income and percentage minority population. Higher transplant rates were seen with increasing median household income and decreasing minority populations but were not influenced by education level. Transplantation rates in counties with poverty rates above the national average had low transplant rates, but these rates were influenced by the poverty level in the surrounding counties. Similarly, wealthy counties had higher transplant rates but were lowered in counties of relative wealth that were surrounded by less wealthy counties. CONCLUSIONS: Our results underline the geographical heterogeneity of kidney transplantation in the United States and identify regions of the country most likely to benefit from interventions that may reduce disparities in transplantation.

Recovery of renal function among ESRD patients in the US medicare program.

BACKGROUND: Patients started on long term hemodialysis have typically had low rates of reported renal recovery with recent estimates ranging from 0.9-2.4% while higher rates of recovery have been reported in cohorts with higher percentages of patients with acute renal failure requiring dialysis. STUDY DESIGN: Our analysis followed approximately 194,000 patients who were initiated on hemodialysis during a 2-year period (2008 & 2009) with CMS-2728 forms submitted to CMS by dialysis facilities, cross-referenced with patient record updates through the end of 2010, and tracked through December 2010 in the CMS SIMS registry. RESULTS: We report a sustained renal recovery (i.e no return to ESRD during the available follow up period) rate among Medicare ESRD patients of > 5% - much higher than previously reported. Recovery occurred primarily in the first 2 months post incident dialysis, and was more likely in cases with renal failure secondary to etiologies associated with acute kidney injury. Patients experiencing sustained recovery were markedly less likely than true long-term ESRD patients to have permanent vascular accesses in place at incident hemodialysis, while non-White patients, and patients with any prior nephrology care appeared to have significantly lower rates of renal recovery. We also found widespread geographic variation in the rates of renal recovery across the United States. CONCLUSIONS: Renal recovery rates in the US Medicare ESRD program are higher than previously reported and appear to have significant geographic variation. Patients with diagnoses associated with acute kidney injury who are initiated on long-term hemodialysis have significantly higher rates of renal recovery than the general ESRD population and lower rates of permanent access placement.

Life's Simple 7 and risk of incident stroke: the reasons for geographic and racial differences in stroke study.

BACKGROUND AND PURPOSE: The American Heart Association developed Life's Simple 7 (LS7) as a metric defining cardiovascular health. We investigated the association between LS7 and incident stroke in black and white Americans. METHODS: The Reasons for Geographic And Racial Differences in Stroke (REGARDS) is a national population-based cohort of 30 239 blacks and whites, aged ≥45 years, sampled from the US population from 2003 to 2007. Data were collected by telephone, self-administered questionnaires, and an in-home examination. Incident strokes were identified through biannual participant contact followed by adjudication of medical records. Levels of the LS7 components (blood pressure, cholesterol, glucose, body mass index, smoking, physical activity, and diet) were each coded as poor (0 point), intermediate (1 point), or ideal (2 points) health. An overall LS7 score was categorized as inadequate (0-4), average (5-9), or optimum (10-14) cardiovascular health. RESULTS: Among 22 914 subjects with LS7 data and no previous cardiovascular disease, there were 432 incident strokes over 4.9 years of follow-up. After adjusting for demographics, socioeconomic status, and region of residence, each better health category of the LS7 score was associated with a 25% lower risk of stroke (hazard ratios, 0.75; 95% confidence interval, 0.63-0.90). The association was similar for blacks and whites (interaction P value=0.55). A 1-point higher LS7 score was associated with an 8% lower risk of stroke (hazard ratios, 0.92; 95% confidence interval, 0.88-0.95). CONCLUSIONS: In both blacks and whites, better cardiovascular health, on the basis of the LS7 score, is associated with lower risk of stroke, and a small difference in scores was an important stroke determinant.

High Costs of Dialysis Transportation in the United States: Exploring Approaches to a More Cost-effective Delivery System.

Background: The costs of transporting end-stage renal disease (ESRD) patients to dialysis centers are high and growing rapidly. Research has suggested that substantial cost savings could be achieved if medically appropriate transport was made available and covered by Medicare. Objectives: To estimate US dialysis transportation costs from a purchaser's perspective, and to estimate cost savings that could be achieved if less expensive means of transport were utilized. Methods: Costs were estimated using an actuarial model. Travel distance estimates were calculated using GIS software from patient ZIP codes and dialysis facility addresses. Cost and utilization estimates were derived from fee schedules, government reports, transportation websites and peer-reviewed literature. Results: The estimated annual cost of dialysis transportation in the United States is $3.0 billion, half of which is for ambulances. Most other costs are due to transport via ambulettes, wheelchair vans and taxis. Approximately 5% of costs incurred are for private vehicle or public transportation use. If ambulance use dropped to 1% of trips from the current 5%, costs could be reduced by one-third. Conclusions: Decision-makers should consider policies to reduce ambulance use, while providing appropriate levels of care.

Low income and albuminuria among REGARDS (Reasons for Geographic and Racial Differences in Stroke) study participants.

BACKGROUND: Albuminuria is an important risk factor for progressive chronic kidney disease (CKD) and is more prevalent in black than white adults. We sought to determine the association between low income and albuminuria and whether this association differs for blacks and whites. STUDY DESIGN: Cross-sectional study. SETTING & PARTICIPANTS: 9,144 black and 13,684 white US adults 45 years and older in the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study. PREDICTORS: Self-reported annual household income category (≥$75,000, $35,000-$74,999, $20,000-$34,999, and <$20,000); black and white race. OUTCOMES & MEASUREMENTS: Albuminuria defined as high (30-300 mg/g) or very high (>300 mg/g) urinary albumin-creatinine ratio (ACR). Multinomial logistic regression used to examine the race-stratified association between categories of income and albuminuria (normal, high, or very high ACR). RESULTS: Overall, geometric mean ACR was 10.2 mg/g and was higher for blacks (11.8 mg/g) than whites (9.3 mg/g), P<0.001. Lower income was associated with a higher prevalence of albuminuria for both whites and blacks in unadjusted analyses. After adjustment for demographics, lifestyle factors, comorbid illnesses, and estimated glomerular filtration rate, there was a trend toward a stronger association between lower income levels and high ACR in blacks (ORs of 1.38 [95% CI, 1.07-1.77], 1.36 [95% CI, 1.05-1.75], and 1.58 [95% CI, 1.21-2.05] for income levels of $35,000-$74,999, $20,000-$34,999, and <$20,000, respectively; reference group is those with income≥$75,000) compared with whites (ORs of 0.95 [95% CI, 0.81-1.12], 0.95 [95% CI, 0.79-1.14], and 1.26 [95% CI, 1.02-1.55], respectively); P interaction=0.08 between race and income. Results were similar for very high ACR and subgroups of participants with diabetes or hypertension. LIMITATIONS: Cross-sectional design; not all REGARDS participants provided their annual income. CONCLUSIONS: Lower income may be associated more strongly with albuminuria in blacks than whites and may be a determinant of racial disparities in albuminuria.

Influence of race, ethnicity and socioeconomic status on kidney disease.

Low socioeconomic status (SES) influences disease incidence and contributes to poor health outcomes throughout an individual's life course across a wide range of populations. Low SES is associated with increased incidence of chronic kidney disease, progression to end-stage renal disease, inadequate dialysis treatment, reduced access to kidney transplantation, and poor health outcomes. Similarly, racial and ethnic disparities, which in the USA are strongly associated with lower SES, are independently associated with poor health outcomes. In this Review, we discuss individual-level and group-level SES factors, and the concomitant role of race and ethnicity that are associated with and mediate the development of chronic kidney disease, progression to end-stage renal disease and access to treatment.

Racial disparities in access to pediatric kidney transplantation since share 35.

Share 35 was enacted in 2005 to shorten transplant wait times and provide high-quality donors to children with ESRD. To investigate the possible effect of this policy on racial disparities in access to pediatric transplantation, we analyzed data from the US Renal Data System before and after Share 35. Among 4766 pediatric patients with incident ESRD, the probability of receiving a deceased-donor kidney transplant increased 46% after Share 35, with Hispanics experiencing the greatest improvements (increases of 81% for Hispanics, 45% for blacks, and 37% for whites). On average, patients received a deceased-donor kidney transplant earlier after Share 35, but this finding varied by race: 63 days earlier for whites, 90 days earlier for blacks, and 201 days earlier for Hispanics. Furthermore, a shift from living- to deceased-donor sources occurred with Share 35 for all races, with a 25% reduction in living donors for whites compared with 48% and 46% reductions for Hispanics and blacks, respectively. In summary, Share 35 seems to have attenuated racial disparities in the time to and probability of children receiving a deceased-donor kidney transplant. These changes coincided with changes in the rates of living-donor sources, which vary by race. Future studies should explore how these changes may impact racial differences in long-term graft outcomes.

Epidemiology, geography and chronic kidney disease.

PURPOSE OF REVIEW: Geographic variation in the occurrence and outcomes of chronic kidney disease (CKD) is major area of study in epidemiology and health services and outcomes research. Geographic attributes may be as diverse as the physical, socioeconomic, and medical care characteristics of an environment. This review summarizes the recent literature pertaining to geographic risk factors and CKD. RECENT FINDINGS: Studies have reported on the association between CKD and physical attributes of place (ambient temperature and altitude), the impact of disasters on CKD populations, new diseases characterized by regional localization, national variations in CKD incidence and prevalence, regional variation in end-stage renal disease incidence, residential mobility and CKD risk factors, and geographic variations in CKD care. The emerging role of tools for geospatial studies - including multilevel analytical designs, which reduce the likelihood of an ecologically biased inference, and geographic information systems, which allow the simultaneous linkage, analysis, and mapping of geospatial data - is illustrated by these studies. SUMMARY: Our understanding of the occurrence and outcomes of CKD will continue to be expanded and deepened by the explicit study of attributes associated with place as a potential risk factor. Many of the studies reviewed are largely hypothesis generating, and a better understanding of the role of geography in the study of CKD awaits investigations that probe the mechanisms that link attributes of place to disease processes.

Historical clinical and economic consequences of anemia management in patients with end-stage renal disease on dialysis using erythropoietin stimulating agents versus routine blood transfusions: a retrospective cost-effectiveness analysis.

OBJECTIVE: To determine whether Medicare's decision to cover routine administration of erythropoietin stimulating agents (ESAs) to treat anemia of end-stage renal disease (ESRD) has been a cost-effective policy relative to standard of care at the time. METHODS: The authors used summary statistics from the actual cohort of ESRD patients receiving ESAs between 1995 and 2004 to create a simulated patient cohort, which was compared with a comparable simulated cohort assumed to rely solely on blood transfusions. Outcomes modeled from the Medicare perspective included estimated treatment costs, life-years gained, and quality-adjusted life-years (QALYs). Incremental cost-effectiveness ratio (ICER) was calculated relative to the hypothetical reference case of no ESA use in the transfusion cohort. Sensitivity of the results to model assumptions was tested using one-way and probabilistic sensitivity analyses. RESULTS: Estimated total costs incurred by the ESRD population were $155.47B for the cohort receiving ESAs and $155.22B for the cohort receiving routine blood transfusions. Estimated QALYs were 2.56M and 2.29M, respectively, for the two groups. The ICER of ESAs compared to routine blood transfusions was estimated as $873 per QALY gained. The model was sensitive to a number of parameters according to one-way and probabilistic sensitivity analyses. LIMITATIONS: This model was counter-factual as the actual comparison group, whose anemia was managed via transfusion and iron supplements, rapidly disappeared following introduction of ESAs. In addition, a large number of model parameters were obtained from observational studies due to the lack of randomized trial evidence in the literature. CONCLUSIONS: This study indicates that Medicare's coverage of ESAs appears to have been cost effective based on commonly accepted levels of willingness-to-pay. The ESRD population achieved substantial clinical benefit at a reasonable cost to society.