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.

Interdialytic Weight Gain: Trends, Predictors, and Associated Outcomes in the International Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: High interdialytic weight gain (IDWG) is associated with adverse outcomes in hemodialysis (HD) patients. We identified temporal and regional trends in IDWG, predictors of IDWG, and associations of IDWG with clinical outcomes. STUDY DESIGN: Analysis 1: sequential cross-sections to identify facility- and patient-level predictors of IDWG and their temporal trends. Analysis 2: prospective cohort study to assess associations between IDWG and mortality and hospitalization risk. SETTING & PARTICIPANTS: 21,919 participants on HD therapy for 1 year or longer in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 2 to 5 (2002-2014). PREDICTORS: Analysis 1: study phase, patient demographics and comorbid conditions, HD facility practices. Analysis 2: relative IDWG, expressed as percentage of post-HD weight (<0%, 0%-0.99%, 1%-2.49%, 2.5%-3.99% [reference], 4%-5.69%, and ≥5.7%). OUTCOMES: Analysis 1: relative IDWG as a continuous variable using linear mixed models; analysis 2: mortality; all-cause and cause-specific hospitalization using Cox regression, adjusting for potential confounders. RESULTS: From phase 2 to 5, IDWG declined in the United States (-0.29kg; -0.5% of post-HD weight), Canada (-0.25kg; -0.8%), and Europe (-0.22kg; -0.5%), with more modest declines in Japan and Australia/New Zealand. Among modifiable factors associated with IDWG, the most notable was facility mean dialysate sodium concentration: every 1-mEq/L greater dialysate sodium concentration was associated with 0.13 (95% CI, 0.11-0.16) greater relative IDWG. Compared to relative IDWG of 2.5% to 3.99%, there was elevated risk for mortality with relative IDWG≥5.7% (adjusted HR, 1.23; 95% CI, 1.08-1.40) and elevated risk for fluid-overload hospitalization with relative IDWG≥4% (HRs of 1.28 [95% CI, 1.09-1.49] and 1.64 [95% CI, 1.27-2.13] for relative IDWGs of 4%-5.69% and ≥5.7%, respectively). LIMITATIONS: Possible residual confounding. No dietary salt intake data. CONCLUSIONS: Reductions in IDWG during the past decade were partially explained by reductions in dialysate sodium concentration. Focusing quality improvement strategies on reducing occurrences of high IDWG may improve outcomes in HD patients.

Hemoglobin Concentration and Risk of Incident Stroke in Community-Living Adults.

BACKGROUND AND PURPOSE: In previous observational studies, hemoglobin concentrations have been associated with an increased risk of stroke. However, these studies were limited by a relatively low number of stroke events, making it difficult to determine whether the association of hemoglobin and stroke differed by demographic or clinical factors. METHODS: Using Cox proportional hazards analysis and Kaplan-Meier plots, we examined the association of baseline hemoglobin concentrations with incident stroke in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a cohort of black and white adults aged ≥45 years. RESULTS: A total of 518 participants developed stroke over a mean 7±2 years of follow-up. There was a statistically significant interaction between hemoglobin and sex (P=0.05) on the risk of incident stroke. In Cox regression models adjusted for demographic and clinical variables, there was no association of baseline hemoglobin concentration with incident stroke in men, whereas in women, the lowest (<12.4 g/dL) and highest (>14.0 g/dL) quartiles of hemoglobin were associated with higher risk of stroke when compared with the second quartile (12.4-13.2 g/dL; quartile 1: hazard ratio, 1.59; 95% confidence interval, 1.09-2.31; quartile 2: referent; quartile 3: hazard ratio, 0.91; 95% confidence interval, 0.59-1.38; quartile 4: hazard ratio, 1.59; 95% confidence interval, 1.08-2.35). Similar results were observed in models stratified by hemoglobin and sex and when hemoglobin was modeled as a continuous variable using restricted quadratic spline regression. CONCLUSIONS: Lower and higher hemoglobin concentrations were associated with a higher risk of incident stroke in women. No such associations were found in men.

Friends, social networks, and progressive chronic kidney disease.

A report by Dunkler et al. reminds us that social factors are relevant for today's clinical scientist and practitioner. They report that an increasing number of friends reduces the incidence and progression of chronic kidney disease in type 2 diabetes. The observation that 'friends don't let friends' develop kidney disease suggests that social factors, as well as biomarkers, may be relevant in developing 'personalized renal medicine' and may identify areas for future nephrology research and education.

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.

Obesity, metabolic health, and the risk of end-stage renal disease.

Obesity is associated with chronic kidney disease progression. Whether metabolic risk factors modify this association is unclear. Here we examined associations of body mass index (BMI) and metabolic health with risk of end-stage renal disease (ESRD) in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. Among 21,840 participants eligible for analysis, 247 developed ESRD (mean follow-up of 6.3 years). Metabolic health significantly modified the association of BMI with ESRD. In models stratified by the presence or absence of the metabolic syndrome and adjusted for demographic, lifestyle, and clinical factors, higher BMI was associated with lower risk of ESRD in those without (hazard ratio per 5 kg/m2 increase in BMI 0.70, 95% CI 0.52, 0.95) but not those with (hazard ratio, 1.06) the metabolic syndrome. In models stratified by weight and metabolic health, compared with normal weight (BMI 18.5-24.9 kg/m2) participants without the metabolic syndrome the overweight individuals (BMI 25-29.9) and obese individuals (BMI of 30 or more) with the metabolic syndrome had greater risk of ESRD (hazard ratios of 2.03 and 2.29, respectively), whereas obesity without the metabolic syndrome was associated with lower risk of ESRD (hazard ratio 0.47). Thus, higher BMI is associated with lower ESRD risk in those without but not those with the metabolic syndrome.

Underreporting of nursing home utilization on the CMS-2728 in older incident dialysis patients and implications for assessing mortality risk.

BACKGROUND: The usage of nursing home (NH) services is a marker of frailty among older adults. Although the Centers for Medicare & Medicaid Services (CMS) revised the Medical Evidence Report Form CMS-2728 in 2005 to include data collection on NH institutionalization, the validity of this item has not been reported. METHODS: There were 27,913 patients ≥ 75 years of age with incident end-stage renal disease (ESRD) in 2006, which constituted our analysis cohort. We determined the accuracy of the CMS-2728 using a matched cohort that included the CMS Minimum Data Set (MDS) 2.0, often employed as a "gold standard" metric for identifying patients receiving NH care. We calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the CMS-2728 NH item. Next, we compared characteristics and mortality risk by CMS-2728 and MDS NH status agreement. RESULTS: The sensitivity, specificity, PPV and NPV of the CMS-2728 for NH status were 33%, 97%, 80% and 79%, respectively. Compared to those without the MDS or CMS-2728 NH indicator (No MDS/No 2728), multivariable adjusted hazard ratios (95% confidence interval) for mortality associated with NH status were 1.55 (1.46 - 1.64) for MDS/2728, 1.48 (1.42 - 1.54) for MDS/No 2728, and 1.38 (1.25 - 1.52) for No MDS/2728. NH utilization was more strongly associated with mortality than other CMS-2728 items in the model. CONCLUSIONS: The CMS-2728 underestimated NH utilization among older adults with incident ESRD. The potential for misclassification may have important ramifications for assessing prognosis, developing advanced care plans and providing coordinated care.

Dietary patterns and risk of death and progression to ESRD in individuals with CKD: a cohort study.

BACKGROUND: Nutrition is linked strongly with health outcomes in chronic kidney disease (CKD). However, few studies have examined relationships between dietary patterns and health outcomes in persons with CKD. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: 3,972 participants with CKD (defined as estimated glomerular filtration rate < 60 mL/min/1.73 m2 or albumin-creatinine ratio ≥ 30 mg/g at baseline) from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a prospective cohort study of 30,239 black and white adults at least 45 years of age. PREDICTORS: 5 empirically derived dietary patterns identified by factor analysis: "convenience" (Chinese and Mexican foods, pizza, and other mixed dishes), "plant-based" (fruits and vegetables), "sweets/fats" (sugary foods), "Southern" (fried foods, organ meats, and sweetened beverages), and "alcohol/salads" (alcohol, green-leafy vegetables, and salad dressing). OUTCOMES: All-cause mortality and end-stage renal disease (ESRD). RESULTS: 816 deaths and 141 ESRD events were observed over approximately 6 years of follow-up. There were no statistically significant associations of convenience, sweets/fats, or alcohol/salads pattern scores with all-cause mortality after multivariable adjustment. In Cox regression models adjusted for sociodemographic factors, energy intake, comorbid conditions, and baseline kidney function, higher plant-based pattern scores (indicating greater consistency with the pattern) were associated with lower risk of mortality (HR comparing fourth to first quartile, 0.77; 95% CI, 0.61-0.97), whereas higher Southern pattern scores were associated with greater risk of mortality (HR comparing fourth to first quartile, 1.51; 95% CI, 1.19-1.92). There were no associations of dietary patterns with incident ESRD in multivariable-adjusted models. LIMITATIONS: Missing dietary pattern data, potential residual confounding from lifestyle factors. CONCLUSIONS: A Southern dietary pattern rich in processed and fried foods was associated independently with mortality in persons with CKD. In contrast, a diet rich in fruits and vegetables appeared to be protective.

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.

Low income, community poverty and risk of end stage renal disease.

BACKGROUND: The risk of end stage renal disease (ESRD) is increased among individuals with low income and in low income communities. However, few studies have examined the relation of both individual and community socioeconomic status (SES) with incident ESRD. METHODS: Among 23,314 U.S. adults in the population-based Reasons for Geographic and Racial Differences in Stroke study, we assessed participant differences across geospatially-linked categories of county poverty [outlier poverty, extremely high poverty, very high poverty, high poverty, neither (reference), high affluence and outlier affluence]. Multivariable Cox proportional hazards models were used to examine associations of annual household income and geospatially-linked county poverty measures with incident ESRD, while accounting for death as a competing event using the Fine and Gray method. RESULTS: There were 158 ESRD cases during follow-up. Incident ESRD rates were 178.8 per 100,000 person-years (105 py) in high poverty outlier counties and were 76.3 /105 py in affluent outlier counties, p trend=0.06. In unadjusted competing risk models, persons residing in high poverty outlier counties had higher incidence of ESRD (which was not statistically significant) when compared to those persons residing in counties with neither high poverty nor affluence [hazard ratio (HR) 1.54, 95% Confidence Interval (CI) 0.75-3.20]. This association was markedly attenuated following adjustment for socio-demographic factors (age, sex, race, education, and income); HR 0.96, 95% CI 0.46-2.00. However, in the same adjusted model, income was independently associated with risk of ESRD [HR 3.75, 95% CI 1.62-8.64, comparing the <$20,000 income group to the >$75,000 group]. There were no statistically significant associations of county measures of poverty with incident ESRD, and no evidence of effect modification. CONCLUSIONS: In contrast to annual family income, geospatially-linked measures of county poverty have little relation with risk of ESRD. Efforts to mitigate socioeconomic disparities in kidney disease may be best appropriated at the individual level.

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.

Healthy behaviors, risk factor control and awareness of chronic kidney disease.

BACKGROUND/AIMS: The association between chronic kidney disease (CKD) awareness and healthy behaviors is unknown. We examined whether CKD self-recognition is associated with healthy behaviors and achieving risk-reduction targets known to decrease risk of cardiovascular morbidity and CKD progression. METHODS: CKD awareness, defined as a 'yes' response to 'Has a doctor or other health professional ever told you that you had kidney disease?', was examined among adults with CKD (eGFR <60 ml/min/1.73 m(2)) who participated in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Odds of participation in healthy behaviors (tobacco avoidance, avoidance of regular nonsteroidal anti-inflammatory drug use, and physical activity) and achievement of risk-reduction targets (angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, systolic blood pressure control and glycemic control among those with diabetes) among those aware versus unaware of their CKD were determined by logistic regression, controlling for sociodemographics, access to care and comorbid conditions. Systolic blood pressure control was defined as <130 mm Hg (primary definition) or <140 mm Hg (secondary definition). RESULTS: Of 2,615 participants, only 6% (n = 166) were aware of having CKD. Those who were aware had 82% higher odds of tobacco avoidance compared to those unaware (adjusted OR = 1.82, 95% CI 1.02-3.24). CKD awareness was not associated with other healthy behaviors or achievement of risk-reduction targets. CONCLUSIONS: Awareness of CKD was only associated with participation in one healthy behavior and was not associated with achievement of risk-reduction targets. To encourage adoption of healthy behaviors, a better understanding of barriers to participation in CKD-healthy behaviors is needed.

A public health perspective on CKD and obesity.

End-stage renal disease (ESRD) is a growing health burden for global populations, which has generated keen interest in interventions to prevent or delay the progression of its antecedent chronic kidney disease (CKD). There are biologically plausible mechanisms that link increased adiposity to pathways of kidney injury, animal models of obesity-related kidney disease and specific glomerular disease that is observed in extremely obese humans. Further, individuals with progressive kidney disease and incident ESRD are more obese than their counterparts in the general population. These observations raise the consideration that population-based policies targeted at delaying progressive CKD should recommend interventions for treatment of obesity in these individuals. We examine this proposition first by describing the public health infrastructure that exists to translate CKD public health policy, illustrating it by examples familiar to the practicing nephrologist. Next, we suggest that, despite the evidence supporting an association between increased body weight and progressive CKD, it is premature to contemplate public health recommendations for weight reduction in CKD patients. This prematurity reflects the lack of strong evidence that reduction in body weight delays or prevents the progression of CKD and persistent uncertainty about the direction of the association between obesity and mortality in individuals with advanced kidney failure. We conclude by noting that this position is not that of therapeutic nihilism but rather a caution to approach weight management in CKD on an individual, patient-to-patient basis, and an emphasis for further randomized clinical trials to resolve these uncertainties.

Association of duration of residence in the southeastern United States with chronic kidney disease may differ by race: the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort study.

BACKGROUND: Prior evidence suggests that longer duration of residence in the southeastern United States is associated with higher prevalence of diabetes and hypertension. We postulated that a similar association would exist for chronic kidney disease (CKD). METHODS: In a national population-based cohort study that enrolled 30,239 men and women ≥ 45 years old (42% black/58% white; 56% residing in the Southeast) between 2003 and 2007, lifetime southeastern residence duration was calculated and categorized [none (0%), less than half (>0-< 50%), half or more (≥50-< 100%), and all (100%)]. Prevalent albuminuria (single spot urinary albumin:creatinine ratio of ≥30 mg/g) and reduced kidney function (estimated glomerular filtration rate <60 ml/min/1.73 m2) were defined at enrollment. Incident end-stage renal disease (ESRD) during follow-up was identified through linkage to United States Renal Data System. RESULTS: White and black participants most often reported living their entire lives outside (35.7% and 27.0%, respectively) or inside (27.9% and 33.8%, respectively) the southeastern United States. The prevalence of neither albuminuria nor reduced kidney function was statistically significantly associated with southeastern residence duration, in either race. ESRD incidence was not statistically significantly associated with all vs. none southeastern residence duration (HR = 0.50, 95% CI, 0.22-1.14) among whites, whereas blacks with all vs. none exposure showed increased risk of ESRD (HR = 1.63, 95% CI, 1.02-2.63; PraceXduration = 0.011). CONCLUSIONS: These data suggest that blacks but not whites who lived in the Southeast their entire lives were at increased risk of ESRD, but we found no clear geographic pattern for earlier-stage CKD.

Form CMS-2728 data versus erythropoietin claims data: implications for quality of care studies.

Medical Evidence Report Form CMS-2728 data is frequently used to study US dialysis patients, but the validity of these data have been called into question. We compared predialysis erythropoietin use as recorded on Form CMS-2728 with claims data as part of an assessment of quality of care among hemodialysis patients. Medicare claims were linked to Form CMS-2728 data for 18,870 patients. Dialysis patients, 67 years old or older, who started dialysis from 1 June 2005 to 31 May 2007 were eligible. Logistic and multivariate regressions were used to compare the use of either Form CMS-2728 or the corresponding claims data to predict mortality and the probability of meeting target hemoglobin levels. The sensitivity, specificity, and kappa coefficient for the predialysis erythropoietin indicator were 58.0%, 78.4%, and 0.36, respectively. Patients with a predialysis erythropoietin claim were less likely to die compared with patients without a claim (odds ratio = 0.80 and 95% confidence interval = 0.74-0.87), but there was no relationship observed between predialysis care and death using only Form CMS-2728 predictors. At the facility level, a predialysis erythropoietin claim was associated with a 0.085 increase in the rate of meeting target hemoglobin levels compared with patients without a claim (p = 0.041), but no statistically significant relationship was observed when using the Form CMS-2728 indicators. The agreement between Form CMS-2728 and claims data is poor and discordant results are observed when comparing the use of these data sources to predict health outcomes. Facilities with higher agreement between the two data sources may provide greater quality of care.

Association between urinary albumin excretion and coronary heart disease in black vs white adults.

IMPORTANCE: Excess urinary albumin excretion is more common in black than white individuals and is more strongly associated with incident stroke risk in black vs white individuals. Whether similar associations extend to coronary heart disease (CHD) is unclear. OBJECTIVE: To determine whether the association of urinary albumin excretion with CHD events differs by race. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study of black and white US adults aged 45 years and older who were enrolled within the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study between 2003 and 2007 with follow-up through December 31, 2009. We examined race-stratified associations of urinary albumin-to-creatinine ratio (ACR) in 2 groups: (1) incident CHD among 23,273 participants free of CHD at baseline; and (2) first recurrent CHD event among 4934 participants with CHD at baseline. MAIN OUTCOMES AND MEASURES: Expert-adjudicated incident and recurrent myocardial infarction and acute CHD death. RESULTS: A total of 616 incident CHD events (421 nonfatal MIs and 195 CHD deaths) and 468 recurrent CHD events (279 nonfatal MIs and 189 CHD deaths) were observed over a mean time of 4.4 years of follow-up. Among those free of CHD at baseline, age- and sex-adjusted incidence rates of CHD per 1000 person-years of follow-up increased with increasing categories of ACR in black and white participants, with rates being nearly 1.5-fold greater in the highest category of ACR (>300 mg/g) in black participants (20.59; 95% CI, 14.36-29.51) vs white participants (13.60; 95% CI, 7.60-24.25). In proportional hazards models adjusted for traditional cardiovascular risk factors and medications, higher baseline urinary ACR was associated with greater risk of incident CHD among black participants (hazard ratio [HR] comparing ACR >300 vs <10 mg/g, 3.21 [95% CI, 2.02-5.09]) but not white participants (HR comparing ACR >300 vs <10 mg/g, 1.49 [95% CI, 0.80-2.76]) (P value for interaction = .03). Among those with CHD at baseline, fully adjusted associations of baseline urinary ACR with first recurrent CHD event were similar between black participants (HR comparing ACR >300 vs <10 mg/g, 2.21 [95% CI, 1.22-4.00]) vs white participants (HR comparing ACR >300 vs <10 mg/g, 2.48 [95% CI, 1.61-3.78]) (P value for interaction = .53). CONCLUSIONS AND RELEVANCE: Higher urinary ACR was associated with greater risk of incident but not recurrent CHD in black individuals when compared with white individuals. These data confirm that black individuals appear more susceptible to vascular injury.

High one year mortality in adults with sickle cell disease and end-stage renal disease.

Adequate pre-dialysis care reduces mortality among end-stage renal disease (ESRD) patients. We tested the hypothesis that individuals with ESRD due to sickle cell disease (SCD-ESRD) receiving pre-ESRD care have lower mortality compared to individuals without pre-ESRD care. We examined the association between mortality and pre-ESRD care in incident SCD-ESRD patients who started haemodialysis between 1 June, 2005 and 31 May, 2009 using data provided by the Centers for Medicare and Medicaid Services (CMS). SCD-ESRD was reported for 410 (0·1%) of 442 017 patients. One year after starting dialysis, 108 (26·3%) patients with incident ESRD attributed to SCD died; the hazard ratio (HR) for mortality among patients with SCD-ESRD compared to those without SCD as the primary cause of renal failure was 2·80 (95% confidence interval [CI] 2·31-3·38). Patients with SCD-ESRD receiving pre-dialysis nephrology care had a lower death rate than those with SCD-ESRD who did not receive pre-dialysis nephrology care (HR = 0·67, 95% CI 0·45-0·99). The one-year mortality rate following an ESRD diagnosis was almost three times higher in individuals with SCD when compared to those without SCD but with ESRD and could be attenuated by pre-dialysis nephrology care.

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.

Prevalence of arteriovenous fistulas in incident hemodialysis patients: correlation with patient factors that may be associated with maturation failure.

BACKGROUND: Lok et al previously reported a risk equation for arteriovenous fistula (AVF) maturation failure. It is unclear whether this model or a more comprehensive model correlates with incident AVF use in the US hemodialysis population. STUDY DESIGN: Cross-sectional study. SETTING & PARTICIPANTS: 195,756 adult patients initiating outpatient hemodialysis therapy in the United States between July 1, 2005, and December 31, 2009, with 6 months or more prior nephrology care. PREDICTOR: Patient characteristics (age, peripheral vascular disease, coronary artery disease, and race) populating the AVF maturation failure risk equation and other demographic and clinical variables from the Centers for Medicare & Medicaid Services (CMS) Medical Evidence Report (CMS 2728). OUTCOMES & MEASUREMENTS: AVF use at first outpatient dialysis treatment as recorded on the CMS 2728. RESULTS: Using the risk categories defined by Lok et al, AVF use varied from 19.0% (very high risk) to 25.6% (low risk). In a model using only these risk categories, logistic regression showed lower ORs for moderate-, 0.90 (95% CI, 0.88-0.93); high-, 0.80 (95% CI, 0.78-0.83); and very high-risk patients, 0.68 (95% CI, 0.63-0.73) compared with low risk. In the expanded model, odds were lower for women, blacks, Hispanics, age older than 85 years, diabetes, peripheral vascular disease, congestive heart failure, other cardiac disease, and underweight. Odds were higher for hypertension, overweight, obesity, 12 months or more nephrologist care, most insurance types, and each successive year after 2005. Despite associations, the C statistic for the expanded model was 0.64. LIMITATIONS: This analysis is limited by lack of access creation history before dialysis therapy initiation and minimal external validation of CMS 2728 data. CONCLUSIONS: Clinical risk factors identified by Lok and expanded in this analysis have limited ability to predict incident AVF use. Even patients judged at highest risk can have successful AVF construction and initiate dialysis therapy through a functioning AVF.

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.