Incidence of atherosclerosis by race in the dialysis morbidity and mortality study: a sample of the US ESRD population

White individuals who are on dialysis experience much higher overall and cardiovascular mortality rates than black individuals despite a more favorable risk factor profile, but the incidence of nonfatal cardiovascular disease (CVD) to this racial disparity has not been well studied. A longitudinal study of 16,103 people who had ESRD and were enrolled in the United Renal Data System from 1993 to 1996 was conducted. The incidence of new and recurrent atherosclerotic CVD (ASCVD) events was determined using Medicare claims for hospitalizations and mortality among blacks and whites, stratified by ASCVD at baseline. ASCVD was defined as coronary heart disease, peripheral vascular disease, and cerebrovascular disease. Incidence of new ASCVD in people without ASCVD at baseline was 146.9 per 1000 person-years in whites and 118.7 per 1000 person-years in blacks. Incidence of recurrent ASCVD was 404.1 per 1000 person-years in whites and 317.5 per 1000 person-years in blacks. Whites were 1.35 (95% confidence interval, 1.18 to 1.55) times more likely to develop incident ASCVD compared with blacks and 1.25 (95% confidence interval, 1.14 to 1.36) times more likely to develop recurrent disease after adjusting for traditional CVD and dialysis-related risk factors. Excess risk for recurrent ASCVD in whites compared with blacks was consistently present no matter the duration of dialysis: Hazard ratio 1.42 for 0 to 6 mo and 1.40 for 6 to 12 mo. Whites who are treated with dialysis have a higher incidence of ASCVD than blacks who are on dialysis, both new and recurrent. Although differences in survival before the initiation of dialysis may contribute to the observed difference in ASCVD risk, it is not explained by baseline traditional and dialysis-related ASCVD risk factors.     

Differences between blacks and whites in the incidence of end-stage renal disease and associated risk factors

In the United States, the age-and-gender-adjusted incident rate of end-stage renal disease (ESRD) for blacks has been 4 times higher than that for whites. We analyzed patient information and medical services contained in the Medicare 5% random sample database. White (n = 977,436) and black (n = 77,800) Medicare enrollees who were at least 65 years old on January 1, 1997, were followed from 1999 to 2001. Hierarchical Cox regression models were used to estimate the relative risk of ESRD for blacks (with reference to whites) after adjustment for age and gender, socioeconomic status, special health conditions (anemia, chronic obstructive pulmonary disease, cardiovascular disease), primary causal diseases of ESRD (eg, diabetes, hypertension), diabetes care and preventive care (eg, hemoglobin A1c or lipid testing), and physician visits for primary or specialty care. The relative risk of ESRD for blacks (with reference to whites) was 3.52 (95% confidence interval [CI], 3.25-3.80) after adjustment for age and gender; 2.90 (95% CI, 2.67-3.15) after adjustment for socioeconomic status and special health conditions; and 2.11 (95% CI, 1.94-2.30) after further adjustment for primary causal diseases of ESRD, diabetes care and preventive care, and physician visits. We conclude that a higher prevalence of primary causal diseases of ESRD and lower access to diabetes care, preventive care, and primary physician visits in blacks compared with whites partially accounts for the racial difference in the incidence of ESRD in the elderly Medicare population. Public health policy should focus on improving access to care, which may lower the burden of ESRD in minority and other at-risk populations.     

Racial differences in the incidence of end-stage renal disease in types I and II diabetes mellitus

An increased risk of end-stage renal disease (ESRD) among blacks has been previously shown for most causes of chronic renal failure, including diabetes. Most previous studies have not considered the higher prevalence of diabetes in the black population and have not analyzed relative risk by type of diabetes. We found that the incidence of ESRD among blacks with diabetes was 3.6 times the rate in whites with diabetes. The relative risk for blacks increases progressively with age, reaching a maximum of 6.9 in persons over the age of 65. The incidence of ESRD due to diabetes is higher in the population with type I diabetes (492 per 100,000) than in the population with type II diabetes (71 per 100,000). Blacks have a higher incidence of ESRD in both type I diabetes (odds ratio, 2.96; 95% confidence interval, 1.8 to 4.9) and type II diabetes (odds ratio, 4.9; 95% confidence interval, 3.6 to 6.5). The incidence of ESRD in patients with diabetes varies with age, race, and type of diabetes.     

Racial Differences in Determinants of Live Donor Kidney Transplantation in the United States

Few studies have compared determinants of live donor kidney transplantation (LDKT) across all major US racial‐ethnic groups. We compared determinants of racial‐ethnic differences in LDKT among 208 736 patients who initiated treatment for end‐stage kidney disease during 2005–2008. We performed proportional hazards and bootstrap analyses to estimate differences in LDKT attributable to sociodemographic and clinical factors. Mean LDKT rates were lowest among blacks (1.19 per 100 person‐years [95% CI: 1.12–1.26]), American Indians/Alaska Natives‐AI/ANs (1.40 [1.06–1.84]) and Pacific Islanders (1.10 [0.78–1.84]), intermediate among Hispanics (2.53 [2.39–2.67]) and Asians (3.89 [3.51–4.32]), and highest among whites (6.46 [6.31–6.61]). Compared with whites, the largest proportion of the disparity among blacks (20%) and AI/ANs (29%) was attributed to measures of predialysis care, while the largest proportion among Hispanics (14%) was attributed to health insurance coverage. Contextual poverty accounted for 16%, 4%, 18%, and 6% of the disparity among blacks, Hispanics, AI/ANs and Pacific Islanders but none of the disparity among Asians. In the United States, significant disparities in rates of LDKT persist, but determinants of these disparities vary by race‐ethnicity. Efforts to expand preESKD insurance coverage, to improve access to high‐quality predialysis care and to overcome socioeconomic barriers are important targets for addressing disparities in LDKT.     

Racial differences in end-stage renal disease rates in HIV infection versus diabetes

Few studies have compared the incidence of end-stage renal disease (ESRD) among individuals with the human immunodeficiency virus (HIV) and diabetes. We followed a national sample of 2,015,891 US veterans over a median peroid of 3.7 years for progression to ESRD. The age- and sex-adjusted incidence of ESRD (per 1000 person-years) among HIV-infected black patients was nearly an order of magnitude higher than among HIV-positive white patients, almost twice that of diabetic whites, and similar to that among diabetic blacks. In multivariate Cox proportional hazards analysis, diabetes was associated with an increased risk of ESRD among white patients, but HIV was not. Among black individuals, however, both HIV and diabetes conferred a similar increase in the risk of ESRD (4- to 5-fold increase compared to white individuals without HIV or diabetes). HIV and diabetes carry a similar risk of ESRD among black patients, highlighting the importance of developing strategies to prevent and treat renal disease among HIV-infected black individuals.     

Risk factors for hip fracture among patients with end-stage renal disease

BACKGROUND: Although bone disease is well described among end-stage renal disease (ESRD) patients, little attention has been paid to the occurrence of fracture. We sought to identify factors that are associated with hip fracture among ESRD patients. METHODS: Data from patients who participated in the United States Renal Data System Dialysis Morbidity and Mortality Study Wave 1 were used for this study. Hip fractures occurring among these patients between 1993 and 1996 were identified from Medicare claims data available from the United States Renal Data System. Cox proportional hazards models were used to estimate the risk of hip fracture associated with demographic and medical variables. RESULTS: Of the 4952 patients included in this analysis, 103 sustained a hip fracture. In the multivariate analysis, age (per increasing decade, RR = 1.40, 95% CI 1.20, 1.64), female gender (RR = 2.26, 95% CI 1.48, 3.44), race (blacks compared with whites, RR = 0.58, 95% CI 0.37, 0.91), body mass index (per 1 unit increase, RR 0.89, 95% CI 0.86, 0.93), and the presence of peripheral vascular disease (RR 1.94, 95% CI 1.29, 2.92) were independently associated with hip fracture. Serum intact parathyroid hormone (iPTH), aluminum, diabetes, and bicarbonate levels did not appreciably influence the risk of hip fracture. CONCLUSIONS: Demographic and other characteristics that predict risk of hip fracture in the population at large also do so in ESRD patients. However, we could identify no characteristics of ESRD or its treatment that were independently related to hip fracture incidence.     

Chronic kidney disease after acute kidney injury: a systematic review and meta-analysis

Acute kidney injury may increase the risk for chronic kidney disease and end-stage renal disease. In an attempt to summarize the literature and provide more compelling evidence, we conducted a systematic review comparing the risk for CKD, ESRD, and death in patients with and without AKI. From electronic databases, web search engines, and bibliographies, 13 cohort studies were selected, evaluating long-term renal outcomes and non-renal outcomes in patients with AKI. The pooled incidence of CKD and ESRD were 25.8 per 100 person-years and 8.6 per 100 person-years, respectively. Patients with AKI had higher risks for developing CKD (pooled adjusted hazard ratio 8.8, 95% CI 3.1-25.5), ESRD (pooled adjusted HR 3.1, 95% CI 1.9-5.0), and mortality (pooled adjusted HR 2.0, 95% CI 1.3-3.1) compared with patients without AKI. The relationship between AKI and CKD or ESRD was graded on the basis of the severity of AKI, and the effect size was dampened by decreased baseline glomerular filtration rate. Data were limited, but AKI was also independently associated with the risk for cardiovascular disease and congestive heart failure, but not with hospitalization for stroke or all-cause hospitalizations. Meta-regression did not identify any study-level factors that were associated with the risk for CKD or ESRD. Our review identifies AKI as an independent risk factor for CKD, ESRD, death, and other important non-renal outcomes.     

The prevalence and treatment of end-stage renal disease in an Asian child population

Background: There are significant differences in the incidence aetiology of end-stage renal disease (ESRD) between the Asian and white adult population in the UK. The aim of this study as to determine if similar differences occurred in the paediatric ESRD population. Methods: A retrospective study of children with ESRD presenting between 1980 and 1995 in the population served by the Birmingham Children's Hospital. Results: Asian children comprised 7.4% of the total child population (0-13 years). ESRD developed in 165 children (138 white, 27 Asian). The prevalence of ESRD for whites was 15 per 10⁵ white child population and for Asians, 40 per 10⁵ Asian child population. A genetic aetiology was noted in 16 (19%) whites and 12 (44%) Asians (P <0.001). Of the 147 renal transplants, 22 (15%) were to Asian recipients. The distribution of blood groups in the two populations reflected the pattern in the respective general populations as a whole. There was no significant difference in time to transplantation for the two groups (whites, mean 6 months, 95% confidence interval 6-11 months; Asians, mean 7 months, 95% CI 4-12 months). Asian patients had significantly more mismatches (⩽3 or ⩽4) compared to white patients. Conclusion: Asian children had a higher prevalence of ESRD, with genetic disease predominating. Differences in ethnicity or blood group did not influence time to transplantation in those that received a transplant although Asians had more mismatches.     

Albuminuria and racial disparities in the risk for ESRD

The causes of the increased risk for ESRD among African Americans are not completely understood. Here, we examined whether higher levels of urinary albumin excretion among African Americans contributes to this disparity. We analyzed data from 27,911 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study who had urinary albumin-to-creatinine ratio (ACR) and estimated GFR (eGFR) measured at baseline. We identified incident cases of ESRD through linkage with the United States Renal Data System. At baseline, African Americans were less likely to have an eGFR <60 ml/min per 1.73 m(2) but more likely to have an ACR ≥ 30 mg/g. The incidence rates of ESRD among African Americans and whites were 204 and 58.6 cases per 100,000 person-years, respectively. After adjustment for age and gender, African Americans had a fourfold greater risk for developing ESRD (HR 4.0; 95% CI 2.8 to 5.9) compared with whites. Additional adjustment for either eGFR or ACR reduced the risk associated with African-American race to 2.3-fold (95% CI 1.5 to 3.3) or 1.8-fold (95% CI 1.2 to 2.7), respectively. Adjustment for both ACR and eGFR reduced the race-associated risk to 1.6-fold (95% CI 1.1 to 2.4). Finally, in a model that further adjusted for both eGFR and ACR, hypertension, diabetes, family income, and educational status, African-American race associated with a nonsignificant 1.4-fold (95% CI 0.9 to 2.3) higher risk for ESRD. In conclusion, the increased prevalence of albuminuria may be an important contributor to the higher risk for ESRD experienced by African Americans.     

Racial and ethnic differences in trends of end-stage renal disease: United States, 1995 to 2005

End-stage renal disease (ESRD) disproportionately affects racial/ethnic minority populations in the United States, whereas the prevalence of ESRD risk factors such as diabetes continues to increase. Using data from the US Renal Data System, we examined trends in ESRD incidence, including ESRD caused by diabetes or hypertension. We determined the total number of persons in the United States by race/ethnicity who began treatment during 1995 to 2005 for ESRD and for ESRD with diabetes or hypertension as the primary diagnosis. Incidence rates were calculated by using census data and age-adjusted based on the 2000 US standard population. Joinpoint regression was used to analyze trends. Overall, during 1995 to 2005, the age-adjusted ESRD incidence increased from 260.7 per million to 350.9 per million, but the rate of increase slowed from 1998 to 2005. In the 2000s, compared with the 1990s, the age-adjusted ESRD incidence has continued to increase but at a slower rate among whites and blacks and has decreased significantly among Native Americans, Asians, and Hispanics. The disparity gap in ESRD incidence between minority populations and whites narrowed during 1995 to 2005. Continued interventions to reduce the prevalence of ESRD risk factors are needed to decrease ESRD incidence.     

Racial and ethnic differences in incident myocardial infarction in end-stage renal disease patients: The USRDS

African Americans have a greater risk of cardiovascular disease (CVD) than Caucasians in early chronic kidney disease; however, limited data describe racial and ethnic differences in the risk of incident myocardial infarction (MI) among patients with end-stage renal disease (ESRD). We conducted a prospective, observational cohort study among 271 102 incident dialysis patients receiving renal replacement therapy enrolled in the United States Renal Data System (USRDS) for whom Medicare was the primary insurer between 1995 and 2000. The incidence and risk of any MI (non-fatal or fatal) estimated by Cox proportional hazards models was the primary outcome of interest. Of those with prevalent CVD at baseline (118 708), 14 849 had an incident non-fatal MI compared with 9926 events for those without prevalent CVD (152 394). Patients with prevalent CVD had higher crude rates of combined fatal and non-fatal MI (99.3/1000 person-years vs 42.9/1000 person-years) compared with those without prevalent CVD. Among those with prevalent CVD, African Americans (adjusted relative risk (aRR)=0.65, 95% confidence interval (CI):0.62-0.68), Asian Americans (aRR=0.74, 95% CI: 0.66-0.83), and Hispanics (aRR=0.72, 95% CI: 0.68-0.77) were 26-35% less likely to have an incident MI compared to Caucasians. Similarly, among those without prevalent CVD, racial/ethnic minorities were 26-42% less likely to have an incident MI compared to Caucasians. We conclude that in a national setting where comparable access to dialysis and associated medical care, exist, racial/ethnic minorities were found to have a lower risk of non-fatal and fatal MI than Caucasians.     

Relationships of race and ethnicity to progression of kidney dysfunction and clinical outcomes in patients with chronic kidney failure

In the United States, the incidence of end-stage renal disease (ESRD) is much higher for blacks, Native Americans, and Asians than for whites. The incidence of kidney disease is also higher for populations of Hispanic ethnicity. ESRD attributed to diabetes (ESRD-DM), hypertension (ESRD-HT), and glomerulonephritis (ESRD-GN), in this order of frequency, are the major categories of ESRD in the United States for all race/ethnic groups. By using the incidence rates of ESRD, during the period from 1997 through 2000, and with whites as reference, the highest rate ratio (RR) was observed for ESRD-HT in blacks (RR = 5.96), ESRD-DM in Native Americans (RR = 5.11), and ESRD-GN in Asians (RR=2.20). The data suggest that the excess of ESRD observed for racial/ethnic minorities may be reduced by interventions aimed at prevention/control of hypertension and diabetes. The data suggest that before developing ESRD, patients with chronic renal failure from minority groups have to face more barriers to receive high-quality health care. This may explain why they see nephrologists later and are less likely to receive renal transplantation at initiation of renal replacement therapy (RRT). Improvements in quality of care after initiating RRT may explain the lower mortality and higher scores in heath-related quality of life observed for patients from racial/ethnic minorities.     

Racial and Ethnic Differences in Pediatric Access to Preemptive Kidney Transplantation in the United States

Preemptive kidney transplantation is the optimal treatment for pediatric end stage renal disease patients to avoid increased morbidity and mortality associated with dialysis. It is unknown how race/ethnicity and poverty influence preemptive transplant access in pediatric. We examined the incidence of living donor or deceased donor preemptive transplantation among all black, white, and Hispanic children (<18 years) in the United States Renal Data System from 2000 to 2009. Adjusted risk ratios for preemptive transplant were calculated using multivariable‐adjusted models and examined across health insurance and neighborhood poverty levels. Among 8,053 patients, 1117 (13.9%) received a preemptive transplant (66.9% from LD, 33.1% from DD). In multivariable analyses, there were significant racial/ethnic disparities in access to LD preemptive transplant where blacks were 66% (RR = 0.34; 95% CI: 0.28–0.43) and Hispanics 52% (RR = 0.48; 95% CI: 0.35–0.67) less likely to receive a LD preemptive transplant versus whites. Blacks were 22% less likely to receive a DD preemptive transplant versus whites (RR = 0.78, 95% CI: 0.57–1.05), although results were not statistically significant. Future efforts to promote equity in preemptive transplant should address the critical issues of improving access to pre‐ESRD nephrology care and overcoming barriers in living donation, including obstacles partially driven by poverty.     

Differential mortality and transplantation rates among Asians and Pacific Islanders with ESRD

Few studies in patients with ESRD have examined outcomes in Asian or Pacific Islander subgroups compared with white individuals. The objective of this study was to assess ethnic disparities in mortality and kidney transplantation among a multiethnic cohort of incident dialysis patients. A total of 24,963 patients who initiated dialysis within the TransPacific Renal Network (Network 17) between April 1, 1995, and September 30, 2001, were studied to ascertain death and kidney transplantation through September 30, 2002. Overall, 12,902 deaths and 2258 kidney transplantations were observed during 59,075 person-years of follow-up. Mortality on dialysis among Asians and Pacific Islanders (except Chamorros) was lower than that of white individuals after controlling for differences in sociodemographic characteristics, comorbid conditions, and other risk factors for death (adjusted hazard ratio [95% confidence interval] versus white individuals: Japanese 0.64 [0.57 to 0.72], Chinese 0.64 [0.52 to 0.78], Filipino 0.64 [0.57 to 0.72], Native Hawaiian 0.84 [0.72 to 0.96], Samoan 0.62 [0.48 to 0.82], and Chamorro 0.96 [0.84 to 1.20]). In contrast, Asians and Pacific Islanders were much less likely to undergo kidney transplantation (adjusted rate ratio [95% confidence interval] versus white individuals: Japanese 0.34 [0.24 to 0.46], Chinese 0.54 [0.30 to 0.88], Filipino 0.32 [0.26 to 0.47], Native Hawaiian 0.17 [0.10 to 0.30], Samoan 0.17 [0.07 to 0.38], and Chamorro 0.04 [0.01 to 0.14]). Despite wide variations in primary cause of ESRD, clinical characteristics, and body size at dialysis initiation, Asians and Pacific Islanders experience better survival but substantially lower transplantation rates compared with white individuals. Strategies that are aimed at improving access to transplantation in Asian and Pacific Islander communities may further enhance survival among Asians and Pacific Islanders with ESRD.     

Predictors of amputation and survival following lower extremity revascularization in hemodialysis patients

BACKGROUND: Peripheral vascular disease (PVD) has become increasingly common in end-stage renal disease (ESRD) patients, leading to an increase in the rate of revascularization and amputation. We studied the prognosis of ESRD patients undergoing their first revascularization procedure. METHODS: We conducted a longitudinal cohort study of hemodialysis patients enrolled in special studies of the United States Renal Data System. Cox proportional hazards analysis was used to assess the independent effect of type of initial revascularization procedure on lower extremity amputation and all-cause, cardiac, and infectious mortality over 3 years, after adjustment for sociodemographic, clinical, and biologic baseline characteristics. RESULTS: Eight hundred patients underwent an initial revascularization procedure by surgical bypass or angioplasty. The overall incidence of subsequent amputation was 16.3/100 person-years, 22.6 for bypass, and 5.7 for angioplasty. After adjustment for patient characteristics, the risk of amputation was higher for bypass versus angioplasty [relative hazard (RH) 4.00; 95% CI 2.46 to 6.57], for black versus white patients (RH 1.49; 95% CI 1.04 to 2.15), for uninsured or patients on Medicaid versus patients with private insurance or on Medicare (RH 1.65; 95% CI 1.12 to 2.72), and for patients with diabetes versus no diabetes (RH 2.51; 95% CI 1.67 to 3.76). Compared with patients who underwent angioplasty, the risk of all-cause (RH 1.37; 95% CI 1.10 to 1.70), cardiac (RH 1.50; 95% CI 1.08 to 2.09), and infectious (RH 2.17; 95% CI 1.10 to 4.29) mortality was greater among patients who underwent bypass. CONCLUSION: Risk of amputation following revascularization procedures was positively associated with type of procedure, black race, uninsured/Medicaid, and diabetes status. Risk of death was also higher following bypass. While this might reflect underlying severity of disease, patient education, screening, and optimal care of lower extremities should be emphasized to detect PVD at an early stage of the disease process.     

Trends in the incidence of treated end-stage renal disease secondary to diabetic nephropathy: 1975-1984

A study of the incidence of treated end-stage renal disease (ESRD) secondary to diabetic nephropathy (DN) in Missouri from 1975 to 1984 documented a relative risk of treated ESRD due to DN 3.7 times higher for blacks than whites. Between 1980 and 1984, the incidence rate for treated ESRD due to DN increased by 150% for white patients and 315% for black patients. Blacks over age 50 have incidence rates of treated ESRD due to DN 4.9 times their white counterparts. Black females have the highest rate of all race/sex groups with DN. The escalating high risk of older blacks for treated ESRD due to DN mandates the development of effective community based identification and referral efforts.     

APOL1 Genotype and Race Differences in Incident Albuminuria and Renal Function Decline

Variants in the APOL1 gene are associated with kidney disease in blacks. We examined associations of APOL1 with incident albuminuria and kidney function decline among 3030 young adults with preserved GFR in the Coronary Artery Risk Development in Young Adults (CARDIA) study. eGFR by cystatin C (eGFRcys) and albumin-to-creatinine ratio were measured at scheduled examinations. Participants were white (n=1700), high-risk black (two APOL1 risk alleles, n=176), and low-risk black (zero/one risk allele, n=1154). Mean age was 35 years, mean eGFRcys was 107 ml/min per 1.73 m², and 13.2% of blacks had two APOL1 alleles. The incidence rate per 1000 person-years (95% confidence interval) for albuminuria over 15 years was 15.6 (10.6–22.1) for high-risk blacks, 7.8 (6.4–9.4) for low-risk blacks, and 3.9 (3.1–4.8) for whites. Compared with whites, the odds ratio (95% confidence interval) for incident albuminuria was 5.71 (3.64–8.94) for high-risk blacks and 2.32 (1.73–3.13) for low-risk blacks. Adjustment for risk factors attenuated the difference between low-risk blacks and whites (odds ratio 1.21, 95% confidence interval 0.86–1.71). After adjustment, high-risk blacks had a 0.45% faster yearly eGFRcys decline over 9.3 years compared with whites. Low-risk blacks also had a faster yearly eGFRcys decline compared with whites, but this difference was attenuated after adjustment for risk factors and socioeconomic position. In conclusion, blacks with two APOL1 risk alleles had the highest risk for albuminuria and eGFRcys decline in young adulthood, whereas disparities between low-risk blacks and whites were related to differences in traditional risk factors.     

Neighborhood poverty and racial differences in ESRD incidence

Poverty is associated with increased risk of ESRD, but its contribution to observed racial differences in disease incidence is not well-defined. To explore the contribution of neighborhood poverty to racial disparity in ESRD incidence, we analyzed a combination of US Census and ESRD Network 6 data comprising 34,767 patients that initiated dialysis in Georgia, North Carolina, or South Carolina between January 1998 and December 2002. Census tracts were used as the geographic units of analysis, and the proportion of the census tract population living below the poverty level was our measure of neighborhood poverty. Incident ESRD rates were modeled using two-level Poisson regression, where race, age and gender were individual covariates (level 1), and census tract poverty was a neighborhood covariate (level 2). Neighborhood poverty was strongly associated with higher ESRD incidence for both blacks and whites. Increasing poverty was associated with a greater disparity in ESRD rates between blacks and whites, with the former at greater risk. This raises the possibility that blacks may suffer more from lower socioeconomic conditions than whites. The disparity persisted across all poverty levels. The reasons for increasingly higher ESRD incidence among US blacks as neighborhood poverty increases remain to be explained.     

Racial differences in the progression from chronic renal insufficiency to end-stage renal disease in the United States

Black Americans experience a disproportionate burden of ESRD compared with whites. Whether this is caused by the increased prevalence of chronic renal insufficiency (CRI) among blacks or by their increased progression from CRI to ESRD was investigated. A birth cohort analysis was performed using data from the Third National Health and Nutrition Examination Survey and the United States Renal Data System. It was assumed that those who developed ESRD in 1996 aged 25 to 79 yr came from the source population with CRI aged 20 to 74 yr that was sampled in the Third National Health and Nutrition Examination Survey (midpoint 1991). GFR was estimated using the Modification of Diet in Renal Disease study equation. The prevalence of CRI (GFR 15 to 59 ml/min per 1.73 m(2)) was not different among black compared with white adults (2060 versus 2520 per 100,000; P = 0.14). For each 100 blacks with CRI in 1991, five new cases of ESRD developed in 1996, whereas only one case of ESRD developed per 100 whites with CRI (risk ratio, 4.8; 95% confidence interval, 2.9 to 8.4). The increased risk for blacks compared with whites was only modestly affected by adjustment for age, gender, and diabetes. Blacks with CRI had higher systolic (147 versus 136 mmHg; P = 0.001) and diastolic (82 versus 77 mmHg; P = 0.02) BP and greater albuminuria (422 versus 158 micro g urine albumin/mg urine creatinine; P = 0.01). The higher incidence of ESRD among blacks is not due to a greater prevalence of CRI among blacks. The key to understanding black-white differences in ESRD incidence lies in understanding the extreme differences in their progression from CRI to ESRD.