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Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
 
Am J Kidney Dis. Author manuscript; available in PMC 2011 June 1.
Published in final edited form as:
PMCID: PMC2876222
NIHMSID: NIHMS167050

Reappraisal of the Impact of Race on Survival in Patients on Dialysis

Abstract

Racial differences in the etiology, natural history and effects of chronic kidney disease have long been the subject of investigation. Dialysis-dependent kidney failure occurs nearly four times more often in African Americans than European Americans. Despite this observation, studies repeatedly demonstrate that African Americans have a significant survival advantage after initiating dialysis. Although this phenomenon has been attributed to environmental and socioeconomic factors, recent studies demonstrate that inherited factors strongly influence racial differences in development of diverse kidney diseases and may impact the risk for nephropathy-associated cardiovascular disease. Herein we review relevant studies and propose the hypothesis that inherited factors leading to organ-limited kidney diseases and a lower burden of systemic atherosclerosis contribute, in part, to the improved survival rates seen in African American patients on dialysis.

Keywords: African Americans, chronic kidney disease, dialysis, race, European Americans, genetics, survival

Prevalence of Kidney Failure

Racial Differences

All studies agree that the prevalence of kidney failure is higher in African Americans than European Americans by a factor of at least two 1,2. Postulated causes include increased prevalence of early stage chronic kidney disease (CKD), higher CKD progression rates, and lower mortality rates (survival advantage) in the earlier stages of CKD in African Americans.

Using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation for estimating glomerular filtration rate (GFR) in the NHANES III (Third National Health and Nutrition Examination Survey) study population, the overall 13% adult prevalence of CKD is concentrated in the early stages (Stage I-III), with a prevalence of only 0.35% in advanced (Stage IV) CKD3. Using the that same formula in four populations, early stages of CKD were less prevalent in African Americans compared to European Americans 48 (Table 1). This racial difference tends to reverse in the more advanced stage of CKD 6,8. Although increased CKD risk was found using the Cockroft-Gault formula for estimating GFR in both NHANES II and REGARDS (Reasons for Geographic and Racial Differences in Stroke) study populations 4,6, this is likely due to higher serum creatinine values in African Americans causing underestimation of GFR9. Increased relative risk for African Americans versus European Americans was also found in the Medicare population where identification of CKD depends on provider coding2,10. If racial differences in early stage CKD prevalence exist, it would imply differences in mechanisms of initiation of kidney disease. This important question will probably not be resolved until more refined techniques for identifying early stage CKD become available.

Table 1
Racial differences in the prevalence of early stage CKD

The sharply lower prevalence of Stage IV CKD indicates that few patients with moderately reduced kidney function progress to kidney failure. Death before development of kidney failure (competing risk) contributes to this phenomenon 8,11,12. The greater relative risk for advanced CKD in African Americans versus European Americans, compared to earlier stages, implies higher progression rates of CKD in African Americans 68,13. This implication is supported by direct measurements of progression rates 8,1316. Racial differences in prevalence of kidney failure are partially explained by differences in incidence and severity of hypertension and diabetes, access to healthcare or socioeconomic status 2,17,18; and an effect of environmental factors on progression of CKD is suggested by the similar progression rates seen in African American and European American Veterans Administration (VA) patients with equivalent access to care 12. However, higher progression rates in African Americans were found in the MDRD trial in which care was standardized 15, and in a large VA population where access to care was similar 8; in the latter study, no correction for differences in blood pressure control was possible. In the AASK (African American Study of Kidney Disease and Hypertension) trial, African Americans with CKD reportedly due to hypertensive nephrosclerosis progressed despite excellent hypertension control and use of angiotensin converting enzyme (ACE) inhibitors 19. Interestingly, African Americans in AASK were much more likely to progress to kidney failure than to die of cardiovascular causes, the opposite result from that observed in general, racially mixed populations 7,8,11,20. Further studies are needed to characterize racial differences in kidney disease progression rates and the extent to which they contribute to the increased incidence of kidney failure in African Americans; unfortunately AASK lacked a European American group for comparison.

A higher mortality in European Americans compared to African Americans in the early stages of CKD could contribute to an increased prevalence of kidney failure in African Americans versus European Americans. However, most studies show just the opposite 8,21, a phenomenon that may contribute to the lower mortality rates in African Americans with advanced CKD and kidney failure.

Heredity and Racial Differences

African Americans have incidence rates of kidney failure attributed to type 2 diabetes mellitus, “hypertension-associated” nephropathy, and organ-limited (focal segmental glomerulosclerosis [FSGS]) and systemic (human immunodeficiency virus-associated nephropathy [HIVAN]) glomerular diseases far exceeding those in European Americans 22. Relative to European Americans, African Americans in the southeast and central eastern seaboard have a 4–20 fold higher risk for developing “hypertensive nephropathy” 23,24. Collapsing FSGS from HIV infection nearly always occurs in African Americans 25. Major roles for inherited factors underlying racial differences in disease causation are supported by familial clustering of kidney failure and MYH9 (non-muscle myosin heavy chain 9) gene associations.

Familial aggregation of CKD and kidney failure has been observed for nephropathy associated with diabetes 2628, hypertension 29,30, HIV infection 31 and systemic lupus erythematosus (SLE) 32. Among nearly 26,000 incident dialysis patients, African American race was an independent risk factor for familial aggregation 30. Familial clustering of kidney failure due to multiple etiologies within single families suggested the existence of generalized kidney disease “susceptibility genes” 28,29,33,34.

This prediction held true with demonstration of the strong association between MYH9 and CKD in African Americans 3538. Significant association was detectable in idiopathic FSGS, HIVAN, and kidney disease attributed to hypertension and type 2 diabetes (Table 2). The MYH9 gene accounts for approximately 70% of non-diabetes associated kidney failure and 16% of diabetes-associated kidney failure in African Americans, approximately 43% of all kidney failure in this racial group. Strong association between MYH9 and FSGS is present in European Americans, but the attributable risk is far lower due to a 4% frequency of risk alleles compared to 60% in African Americans 35,39,40. MYH9 gene–environment and/or gene-gene interactions appear necessary to initiate nephropathy, since not all genetically susceptible individuals will develop nephropathy 37.

Table 2
Genetic association results in MYH9-associated nephropathy studies

Survival in Kidney Failure

Racial Differences

National and regional studies reveal consistent and clinically significant survival advantages in African Americans on dialysis, relative to European Americans 1,4144. The survival advantage remains after adjustment for age, co-morbidity, socioeconomic disparities and differences in rates of kidney transplant and dialysis withdrawal. One study reported that racial differences in kidney failure survival could be eliminated by the combined effects of case mix and treatment variables 42; however, the persistence of survival differences in a randomized clinical trial with tightly controlled treatment parameters supports additional, unidentified factors 45. African Americans have higher serum creatinine concentrations than European Americans at dialysis initiation 41,42 and higher serum creatinine levels are independent predictors of reduced mortality 4648. This finding could affect the time of starting dialysis and hence outcomes on dialysis 49, but the mechanism(s) of the higher serum creatinine levels in African Americans and its associated survival advantage has not been elucidated. 48

The lower mortality rates in African Americans with kidney failure stand in stark contrast to their higher mortality rates in the general population 5052 and in those with the earlier stages of CKD 7,8,53,54. Mortality rates in African Americans may be affected by differences in access to care and other socioeconomic factors, as two VA studies providing equal access to care reveal lower mortality rates in African Americans with CKD 12 and diabetes 55. Survival of a “healthier” population of African Americans who develop kidney failure may contribute to the lower mortality. 42,54 Since nearly 50% of deaths in dialysis patients are due to cardiovascular disease (CVD) 22, particularly sudden cardiac death 56,57, the surprising finding of a reduced prevalence of CVD in African Americans initiating dialysis (Table 3)41,48,5861 likely contributes to their survival advantage. While survival bias may be a factor, we propose that the lower prevalence of CVD in African Americans has two biologic causes: the clustering of MYH9–associated nephropathy and a genetic mechanism that reduces atherosclerosis.

Table 3
Racial differences in prevalence of coronary artery disease in incident dialysis patients

Association with MYH9

The disease historically labeled “hypertensive nephrosclerosis” reportedly causes 35% of kidney failure in African Americans and 25% in European Americans22; but has different pathologic mechanisms and clinical associations between racial groups (Table 4). African Americans have more severe nephropathy with greater numbers of solidified glomeruli (focal global glomerulosclerosis) and interstitial fibrosis, vascular changes (arteriolar nephrosclerosis) that do not correlate with level of blood pressure 62,63, and a strong association with MYH9 polymorphisms 38. European Americans labeled with hypertensive nephrosclerosis are typically older, more often have arteriolar nephrosclerosis, and a stronger association with generalized atherosclerosis involving the coronary and carotid arteries 64,65. We believe that African Americans with MYH9–associated nephropathies are more likely to have organ-limited kidney diseases (e.g., FSGS and focal global glomerulosclerosis) with less extra-renal atherosclerosis. This results in lower CVD rates on starting renal replacement therapy, compared to older European Americans with diffuse large vessel atherosclerosis. Hypertensive kidney failure in African Americans appears to be a misnomer unrelated to high blood pressure 19 and is strongly associated with MYH9 in AASK participants.66 This likely explains why strict blood pressure control and use of ACE inhibitors failed to halt kidney disease progression in AASK and other studies 37,67.

Table 4
Discordant phenotypes in hypertension-associated nephropathy, by race

Potential Differences in Extra-renal Cardiovascular Disease

In addition to the MYH9 nephropathy phenotype, there are growing indications that other hereditary factors contribute to a phenotype with reduced CVD in African Americans.

Two large studies in patients with diabetes (without advanced nephropathy) having equal access to medical care at the VA and Kaiser Permanente revealed 50% lower rates of myocardial infarction in African Americans, relative to European Americans. This surprising result was seen despite poorer glycemic and blood pressure control in African Americans 68,69. These results appear relevant to the issue of dialysis survival, since nearly 50% of incident dialysis patients have diabetes. The pre-dialysis course of CVD in diabetic patients could contribute to racial variation in survival.

Computed tomography-derived coronary artery calcified atherosclerotic plaque, a marker of atherosclerosis and strong predictor of future CVD events 70, is markedly lower in diabetic and non-diabetic African Americans, relative to European Americans 7175. The lower rates of myocardial infarction in African Americans with diabetes, present well before advanced nephropathy develops, are likely associated with this phenomenon. Extra-cranial carotid artery atherosclerosis also demonstrates racial differences in the general population that appear biologically mediated. Carotid artery atherosclerosis is more often present (and severe) in European Americans, whereas African Americans with stroke more commonly have intracranial small vessel cerebrovascular disease 7678.

We demonstrated that the burden of calcified atherosclerotic plaque in the carotid, coronary and aorta of patients with type 2 diabetes correlated with albuminuria in European Americans, but not African Americans73,79. As diabetes-associated CKD progresses with increasing albuminuria, atherosclerosis would appear more likely to develop in European Americans. In CKD and dialysis patients, coronary artery calcified atherosclerotic plaque is increased relative to individuals without CKD or known coronary artery disease.80,81 We are unaware of reports evaluating racial differences in coronary artery calcified atherosclerotic plaque in large numbers of incident dialysis patients. A report in prevalent dialysis patients (81 African Americans and 61 European Americans) did not reveal racial differences in coronary artery calcified atherosclerotic plaque 82. However, these patients had been on dialysis for 4 years and likely had vascular disease relating to factors such as longstanding hyperphosphatemia, vitamin D deficiency, and use of calcium-containing phosphate binders. These environmental exposures would be likely to overwhelm inherited predisposition to atherosclerotic CVD; thus, incident dialysis patients and those not yet on dialysis should be evaluated for racial differences in coronary artery calcified atherosclerotic plaque.

Familial clustering of coronary and carotid artery disease appears to be stronger in European American families, relative to African American 8385. This suggests the existence of susceptibility genes underlying arterial calcification occurring more frequently in European Americans. Relative to European Americans, African Americans with diabetes develop less calcified atherosclerotic plaque in response to smoking and receive greater protection from high-density lipoprotein cholesterol.86 Reduced levels of arterial calcified atherosclerotic plaque in African Americans may be associated with enhanced bone mineralization (lower rates of osteoporosis), despite ingestion of less dietary calcium. Osteoporosis and atherosclerosis appear to be linked disease processes 87 and blood vessels acquire calcified atherosclerotic plaque as vascular cells assume osteoblastic phenotypes 88. It is clear that conventional CVD risk factors must have differential effects on development of atherosclerosis between races86,89 and it is unlikely that these effects relate solely to environmental exposures. It may prove difficult to demonstrate differential genetic susceptibility in the context of overwhelming environmental risk factors.

The favorable biologic factors leading to reduced CVD rates in African Americans on dialysis (relative to European Americans), may be attenuated by environmental factors such as poor access to healthcare. Lower socioeconomic status likely increases CVD rates in the general African American population. The net result of these competing factors appears to yield a lower burden of CVD in African Americans, despite higher burdens of kidney failure. The combined effects of reduced susceptibility to atherosclerosis and the greater prevalence of MYH9-associated organ-limited kidney diseases at dialysis initiation likely contribute to subsequent survival advantages in African Americans.

Conclusions

The key to understanding African American–European American differences in survival on dialysis likely involves the markedly lower prevalence of CVD in African Americans at initiation of renal replacement therapy 55,61. Since nearly 50% of deaths in dialysis patients are due to CVD, the lower prevalence of CVD in African Americans starting dialysis would be expected to translate into improved survival. Although survival bias due to socioeconomic factors and unequal access to care in the predialysis stages of CKD likely contribute to observed racial differences in dialysis survival, we propose biological explanations based on inherited susceptibility to organ-limited forms of kidney failure, coupled with inherited protection from atherosclerosis in African Americans.

There is a growing realization that differential frequencies of risk alleles in disease genes exist between racial groups. Although we all share >99% of our genome, small differences in genetic make-up have the potential to produce major differences in phenotype. Methods exploiting racial differences in allele frequency are being used to identify genomic regions underlying complex diseases that are more common in certain racial groups 90,91. African Americans have higher frequencies of the MYH9-associated kidney failure gene leading to organ-limited diseases in the spectrum of FSGS. Individuals with MYH9-associated nephropathy, predominantly African Americans, would appear less likely to develop extra-renal vascular disease at dialysis initiation. In addition, marked racial differences exist in susceptibility to development of atherosclerosis and calcified atherosclerotic plaque. In contrast to kidney disease, familial clustering of CVD traits is stronger in European Americans, a racial group more susceptible to risk factors producing systemic atherosclerosis with small vessel arteriolar nephrosclerosis and progressive CKD. Therefore, European Americans may be more likely to develop CVD complications, including death, in the setting of kidney failure. Ongoing genomic analyses in complex human diseases are clarifying these effects. We conclude that environmental factors alone are insufficient to fully explain the striking and consistent survival advantage that is observed in African American patients on dialysis.

Acknowledgments

Support: This work was supported in part by National Institutes of Health grants RO1 DK 070941, RO1 DK 071891, and RO1 DK084149 to Dr Freedman.

Footnotes

Financial Disclosure: The authors declare that they have no relevant financial interests.

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Reference List

1. Agodoa L, Eggers P. Racial and ethnic disparities in end-stage kidney failure- survival paradoxes in African-Americans. Semin Dial. 2007;20:577–585. [PubMed]
2. Xue JL, Eggers PW, Agodoa LY, Foley RN, Collins AJ. Longitudinal study of racial and ethnic differences in developing end-stage renal disease among aged medicare beneficiaries. J Am Soc Nephrol. 2007;18:1299–1306. [PubMed]
3. Coresh J, Selvin E, Stevens LA, et al. Prevalence of Chronic Kidney Disease in the United States. JAMA: The Journal of the American Medical Association. 2007;298:2038–2047. [PubMed]
4. Coresh J, Astor BC, Greene T, Eknoyan G, Levey AS. Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey. Am J Kidney Dis. 2003;41:1–12. [PubMed]
5. Coresh J, Byrd-Holt D, Astor BC, et al. Chronic kidney disease awareness, prevalence, and trends among U.S. adults, 1999 to 2000. J Am Soc Nephrol. 2005;16:180–188. [PubMed]
6. McClellan W, Warnock DG, McClure L, et al. Racial differences in the prevalence of chronic kidney disease among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Cohort Study. J Am Soc Nephrol. 2006;17:1710–1715. [PubMed]
7. Newsome BB, McClellan WM, Allison JJ, et al. Racial differences in the competing risks of mortality and ESRD after acute myocardial infarction. Am J Kidney Dis. 2008;52:251–261. [PubMed]
8. Choi AI, Rodriguez RA, Bacchetti P, Bertenthal D, Hernandez GT, O’Hare AM. White/Black Racial Differences in Risk of End-stage Renal Disease and Death. The American Journal of Medicine. 2009;122:672–678. [PMC free article] [PubMed]
9. Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med. 1999;130(6):461–470. [PubMed]
10. Foley RN, Murray AM, Li S, et al. Chronic kidney disease and the risk for cardiovascular disease, renal replacement, and death in the United States Medicare population, 1998 to 1999. J Am Soc Nephrol. 2005;16:489–495. [PubMed]
11. Keith DS, Nichols GA, Gullion CM, Brown JB, Smith DH. Longitudinal follow-up and outcomes among a population with chronic kidney disease in a large managed care organization. Arch Intern Med. 2004;164:659–663. [PubMed]
12. Kovesdy CP, Anderson JE, Derose SF, Kalantar-Zadeh K. Outcomes associated with race in males with nondialysis-dependent chronic kidney disease. Clin J Am Soc Nephrol. 2009;4:973–978. [PubMed]
13. Hsu CY, Lin F, Vittinghoff E, Shlipak MG. Racial differences in the progression from chronic renal insufficiency to end-stage renal disease in the United States. J Am Soc Nephrol. 2003;14:2902–2907. [PubMed]
14. Walker WG, Neaton JD, Cutler JA, Neuwirth R, Cohen JD. Renal function change in hypertensive members of the Multiple Risk Factor Intervention Trial. Racial and treatment effects. The MRFIT Research Group. JAMA. 1992;268:3085–3091. [PubMed]
15. Hunsicker LG, Adler S, Caggiula A, et al. Predictors of the progression of renal disease in the Modification of Diet in Renal Disease Study. Kidney Int. 1997;51:1908–1919. [PubMed]
16. Regalado M, Yang S, Wesson DE. Cigarette smoking is associated with augmented progression of renal insufficiency in severe essential hypertension. Am J Kidney Dis. 2000;35:687–694. [PubMed]
17. Brancati FL, Whittle JC, Whelton PK, Seidler AJ, Klag MJ. The excess incidence of diabetic end-stage renal disease among blacks. A population-based study of potential explanatory factors. JAMA. 1992;268(21):3079–3084. [PubMed]
18. Tarver-Carr ME, Powe NR, Eberhardt MS, et al. Excess risk of chronic kidney disease among African-American versus white subjects in the United States: a population-based study of potential explanatory factors. J Am Soc Nephrol. 2002;13:2363–2370. [PubMed]
19. Appel LJ, Wright JT, Jr, Greene T, et al. Long-term Effects of Renin-Angiotensin System-Blocking Therapy and a Low Blood Pressure Goal on Progression of Hypertensive Chronic Kidney Disease in African Americans. Archives of Internal Medicine. 2008;168:832–839. [PubMed]
20. Rahman M, Pressel S, Davis BR, et al. Cardiovascular Outcomes in High-Risk Hypertensive Patients Stratified by Baseline Glomerular Filtration Rate. Ann Intern Med. 2006;144:172–180. [PubMed]
21. Newsome BB, McClellan WM, Coffey CS, Allison JJ, Kiefe CI, Warnock DG. Survival Advantage of Black Patients with Kidney Disease after Acute Myocardial Infarction. Clinical Journal of the American Society of Nephrology. 2006;1:993–999. [PubMed]
22. U.S. Renal Data System. USRDS 2008 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases; Bethesda, MD: 2008.
23. Whittle JC, Whelton PK, Seidler AJ, Klag MJ. Does racial variation in risk factors explain black-white differences in the incidence of hypertensive end-stage renal disease? Arch Intern Med. 1991;151:1359–1364. [PubMed]
24. Southeastern Kidney Council Inc. ESRD Network 6: Annual Report, 1993. 2009
25. Cantor ES, Kimmel PL, Bosch JP. Effect of race on expression of acquired immunodeficiency syndrome-associated nephropathy. Arch Intern Med. 1991;151:125–128. [PubMed]
26. Seaquist ER, Goetz FC, Rich S, Barbosa J. Familial clustering of diabetic kidney disease. Evidence for genetic susceptibility to diabetic nephropathy. N Engl J Med. 1989;320(18):1161–1165. [PubMed]
27. Freedman BI, Tuttle AB, Spray BJ. Familial predisposition to nephropathy in African-Americans with non-insulin dependent diabetes mellitus. Am J Kidney Dis. 1995;25:710–713. [PubMed]
28. Lei HH, Perneger TV, Klag MJ, Whelton PK, Coresh J. Familial aggregation of renal disease in a population-based case-control study. J Am Soc Nephrol. 1998;9(7):1270–1276. [PubMed]
29. Freedman BI, Spray BJ, Tuttle AB, Buckalew VM., Jr The familial risk of end-stage renal disease in African Americans. Am J Kidney Dis. 1993;21:387–393. [PubMed]
30. Freedman BI, Volkova NV, Satko SG, et al. Population-based screening for family history of end-stage renal disease among incident dialysis patients. Am J Nephrol. 2005;25(6):529–535. [PubMed]
31. Freedman BI, Soucie JM, Stone SM, Pegram S. Familial clustering of end-stage renal disease in blacks with HIV-associated nephropathy. Am J Kidney Dis. 1999;34(2):254–258. [PubMed]
32. Freedman BI, Wilson CH, Spray BJ, Tuttle AB, Olorenshaw IM, Kammer GM. Familial clustering of end-stage renal disease in blacks with lupus nephritis. Am J Kidney Dis. 1997;29(5):729–732. [PubMed]
33. Freedman BI, Soucie JM, McClellan WM. Family history of end-stage renal disease among incident dialysis patients. J Am Soc Nephrol. 1997;8:1942–1945. [PubMed]
34. Freedman BI. Familial aggregation of end-stage renal failure: Aetiological implications. Nephrol Dial Transplant. 1999;14:295–297. [PubMed]
35. Kopp JB, Smith MW, Nelson GW, et al. MYH9 is a major-effect risk gene for focal segmental glomerulosclerosis. Nat Genet. 2008;40:1175–1184. [PMC free article] [PubMed]
36. Kao WH, Klag MJ, Meoni LA, et al. MYH9 is associated with nondiabetic end-stage renal disease in African Americans. Nat Genet. 2008;40:1185–1192. [PMC free article] [PubMed]
37. Freedman BI, Hicks PJ, Bostrom MA, et al. Polymorphisms in the non-muscle myosin heavy chain 9 gene (MYH9) are strongly associated with end-stage renal disease historically attributed to hypertension in African Americans. Kidney Int. 2009;75:736–745. [PMC free article] [PubMed]
38. Freedman BI, Hicks PJ, Bostrom MA, et al. Non-muscle myosin heavy chain 9 gene MYH9 associations in African Americans with clinically diagnosed type 2 diabetes mellitus-associated ESRD. Nephrol Dial Transplant. 2009;24(11):3366–3371. [PMC free article] [PubMed]
39. Pattaro C, Aulchenko YS, Isaacs A, et al. Genome-wide linkage analysis of serum creatinine in three isolated European populations. Kidney Int. 2009;76:297–306. [PubMed]
40. Freedman BI, Kopp JB, Winkler CA, et al. Polymorphisms in the nonmuscle myosin heavy chain 9 gene (MYH9) are associated with albuminuria in hypertensive African Americans: the HyperGEN study. Am J Nephrol. 2009;29:626–632. [PMC free article] [PubMed]
41. Mesler DE, McCarthy EP, Byrne-Logan S, Ash AS, Moskowitz MA. Does the survival advantage of nonwhite dialysis patients persist after case mix adjustment? Am J Med. 1999;106:300–306. [PubMed]
42. Robinson BM, Joffe MM, Pisoni RL, Port FK, Feldman HI. Revisiting survival differences by race and ethnicity among hemodialysis patients: the Dialysis Outcomes and Practice Patterns Study. J Am Soc Nephrol. 2006;17:2910–2918. [PubMed]
43. Pei YP, Greenwood CM, Chery AL, Wu GG. Racial differences in survival of patients on dialysis. Kidney Int. 2000;58:1293–1299. [PubMed]
44. Bleyer AJ, Tell GS, Evans GW, Ettinger WH, Burkart JM. Survival of patients undergoing renal replacement therapy in one center with special emphasis on racial differences. American Journal of Kidney Diseases. 1996;28:72–81. [PubMed]
45. Eknoyan G, Beck GJ, Cheung AK, et al. Effect of dialysis dose and membrane flux in maintenance hemodialysis. N Engl J Med. 2002;347:2010–2019. [PubMed]
46. Fink JC, Burdick RA, Kurth SJ, et al. Significance of serum creatinine values in new end-stage renal disease patients. Am J Kidney Dis. 1999;34:694–701. [PubMed]
47. Kalantar-Zadeh K, Block G, Humphreys MH, Kopple JD. Reverse epidemiology of cardiovascular risk factors in maintenance dialysis patients. Kidney Int. 2003;63(3):793–808. [PubMed]
48. Trivedi H, Xiang Q, Klein JP. Risk factors for non-fatal myocardial infarction and cardiac death in incident dialysis patients. Nephrol Dial Transplant. 2009;24:258–266. [PubMed]
49. Obrador GT, Arora P, Kausz AT, Ruthazer R, Pereira BJ, Levey AS. Level of renal function at the initiation of dialysis in the U.S. end-stage renal disease population. Kidney Int. 1999;56:2227–2235. [PubMed]
50. Levine RS, Foster JE, Fullilove RE, et al. Black-white inequalities in mortality and life expectancy, 1933–1999: implications for healthy people 2010. Public Health Rep. 2001;116:474–483. [PMC free article] [PubMed]
51. Mensah GA, Brown DW, Croft JB, Greenlund KJ. Major coronary risk factors and death from coronary heart disease: baseline and follow-up mortality data from the Second National Health and Nutrition Examination Survey (NHANES II) Am J Prev Med. 2005;29:68–74. [PubMed]
52. Geronimus AT, Bound J, Waidmann TA, Hillemeier MM, Burns PB. Excess mortality among blacks and whites in the United States. N Engl J Med. 1996;335:1552–1558. [PubMed]
53. Weiner DE, Tighiouart H, Amin MG, et al. Chronic kidney disease as a risk factor for cardiovascular disease and all-cause mortality: a pooled analysis of community-based studies. J Am Soc Nephrol. 2004;15(5):1307–1315. [PubMed]
54. Mehrotra R, Kermah D, Fried L, Adler S, Norris K. Racial differences in mortality among those with CKD. J Am Soc Nephrol. 2008;19:1403–1410. [PubMed]
55. Young BA, Rudser K, Kestenbaum B, Seliger SL, Andress D, Boyko EJ. Racial and ethnic differences in incident myocardial infarction in end-stage renal disease patients: The USRDS. Kidney Int. 2006;69:1691–1698. [PubMed]
56. Karnik JA, Young BS, Lew NL, et al. Cardiac arrest and sudden death in dialysis units. Kidney Int. 2001;60:350–357. [PubMed]
57. Bleyer AJ, Russell GB, Satko SG. Sudden and cardiac death rates in hemodialysis patients. Kidney Int. 1999;55:1553–1559. [PubMed]
58. Cheung AK, Sarnak MJ, Yan G, et al. Atherosclerotic cardiovascular disease risks in chronic hemodialysis patients. Kidney Int. 2000;58:353–362. [PubMed]
59. Stack AG, Bloembergen WE. Prevalence and clinical correlates of coronary artery disease among new dialysis patients in the United States: a cross-sectional study. J Am Soc Nephrol. 2001;12:1516–1523. [PubMed]
60. Volkova N, McClellan W, Soucie JM, Schoolwerth A. Racial disparities in the prevalence of cardiovascular disease among incident end-stage renal disease patients. Nephrol Dial Transplant. 2006;21:2202–2209. [PubMed]
61. Trespalacios FC, Taylor AJ, Agodoa LY, Abbott KC. Incident acute coronary syndromes in chronic dialysis patients in the United States. Kidney Int. 2002;62:1799–1805. [PubMed]
62. Marcantoni C, Ma LJ, Federspiel C, Fogo AB. Hypertensive nephrosclerosis in African Americans versus Caucasians. Kidney Int. 2002;62:172–180. [PubMed]
63. Fogo A, Breyer JA, Smith MC, et al. Accuracy of the diagnosis of hypertensive nephrosclerosis in African Americans: a report from the African American Study of Kidney Disease (AASK) Trial. AASK Pilot Study Investigators. Kidney Int. 1997;51:244–252. [PubMed]
64. Bleyer AJ, Chen R, D’Agostino RB, Jr, Appel RG. Clinical correlates of hypertensive end-stage renal disease. Am J Kidney Dis. 1998;31:28–34. [PubMed]
65. Appel RG, Bleyer AJ, Burkart JM. Does hypertension cause end-stage renal disease in older white patients? Nephron. 1998;78:332–333. [PubMed]
66. Lipkowitz MS, Iyengar S, Molineros J, Langefeld CD, Comeau ME, Klotman PE, Bowden DW, Freeman RG, Khitrov G, Zhang W, Kao WHL, Parekh RS, Choi M, Kopp JB, Winkler CA, Nelson G, Freedman BI, Bottinger EP. the AASK Investigators. Association analysis of the non-muscle myosin heavy chain 9 gene (MYH9) in hypertensive nephropathy: African American Study of Kidney Disease and Hypertension (AASK) J Am Soc Nephol. 2009;20:56A.
67. Freedman BI, Sedor JR. Hypertension-associated kidney disease: perhaps no more. J Am Soc Nephrol. 2008;19:2047–2051. [PubMed]
68. Karter AJ, Ferrara A, Liu JY, Moffet HH, Ackerson LM, Selby JV. Ethnic disparities in diabetic complications in an insured population. JAMA. 2002;287:2519–2527. [PubMed]
69. Young BA, Maynard C, Boyko EJ. Racial differences in diabetic nephropathy, cardiovascular disease, and mortality in a national population of veterans. Diabetes Care. 2003;26:2392–2399. [PubMed]
70. Detrano R, Guerci AD, Carr JJ, et al. Coronary calcium as a predictor of coronary events in four racial or ethnic groups. N Engl J Med. 2008;358(13):1336–1345. [PubMed]
71. Bild DE, Detrano R, Peterson D, et al. Ethnic differences in coronary calcification: the Multi-Ethnic Study of Atherosclerosis (MESA) Circulation. 2005;111(10):1313–1320. [PubMed]
72. Newman AB, Naydeck BL, Whittle J, Sutton-Tyrrell K, Edmundowicz D, Kuller LH. Racial differences in coronary artery calcification in older adults. Arterioscler Thromb Vasc Biol. 2002;22(3):424–430. [PubMed]
73. Freedman BI, Langefeld CD, Lohman KK, et al. Relationship between albuminuria and cardiovascular disease in Type 2 diabetes. J Am Soc Nephrol. 2005;16(7):2156–2161. [PubMed]
74. Budoff MJ, Nasir K, Mao S, et al. Ethnic differences of the presence and severity of coronary atherosclerosis. Atherosclerosis. 2006;187(2):343–350. [PubMed]
75. Carnethon MR, Bertoni AG, Shea S, et al. Racial/Ethnic Differences in Subclinical Atherosclerosis Among Adults With Diabetes: The Multiethnic Study of Atherosclerosis. Diabetes Care. 2005;28:2768–2770. [PubMed]
76. Gorelick PB, Caplan LR, Hier DB, Parker SL, Patel D. Racial differences in the distribution of anterior circulation occlusive disease. Neurology. 1984;34:54–59. [PubMed]
77. Inzitari D, Hachinski VC, Taylor DW, Barnett HJ. Racial differences in the anterior circulation in cerebrovascular disease. How much can be explained by risk factors? Arch Neurol. 1990;47:1080–1084. [PubMed]
78. Gil-Peralta A, Alter M, Lai SM, et al. Duplex Doppler and spectral flow analysis of racial differences in cerebrovascular atherosclerosis. Stroke. 1990;21:740–744. [PubMed]
79. Divers J, Wagenknecht LE, Bowden DW, et al. Ethnic differences in the relationship between albuminuria and calcified atherosclerotic plaque: African American-Diabetes Heart Study. Diabetes Care. 2009 in press. [PMC free article] [PubMed]
80. Braun J, Oldendorf M, Moshage W, Heidler R, Zeitler E, Luft FC. Electron beam computed tomography in the evaluation of cardiac calcifications in chronic dialysis patients. American Journal of Kidney Diseases. 1996;27:394–401. [PubMed]
81. Russo D, Palmiero G, De Blasio AP, Balletta MM, Andreucci VE. Coronary artery calcification in patients with CRF not undergoing dialysis. Am J Kidney Dis. 2004;44:1024–1030. [PubMed]
82. Bellasi A, Veledar E, Ferramosca E, Ratti C, Block G, Raggi P. Markers of vascular disease do not differ in black and white hemodialysis patients despite a different risk profile. Atherosclerosis. 2008;197:242–249. [PubMed]
83. Wagenknecht LE, Bowden DW, Carr JJ, Langefeld CD, Freedman BI, Rich SS. Familial aggregation of coronary artery calcium in families with type 2 diabetes. Diabetes. 2001;50(4):861–866. [PubMed]
84. Lange LA, Bowden DW, Langefeld CD, et al. Heritability of carotid artery intima-medial thickness in type 2 diabetes. Stroke. 2002;33(7):1876–1881. [PubMed]
85. Peyser PA, Bielak LF, Chu JS, et al. Heritability of coronary artery calcium quantity measured by electron beam computed tomography in asymptomatic adults. Circulation. 2002;106(3):304–308. [PubMed]
86. Wagenknecht LE, Bertoni AG, Divers J, Langefeld CD, Carr JJ, Bowden DW, Shea S, Freedman BI. Correlates of coronary artery calcified plaque in African Americans and European Americans with diabetes. Diabetes. 2009;58(Suppl 1):A252.
87. Schulz E, Arfai K, Liu X, Sayre J, Gilsanz V. Aortic calcification and the risk of osteoporosis and fractures. J Clin Endocrinol Metab. 2004;89:4246–4253. [PubMed]
88. Shao JS, Cai J, Towler DA. Molecular mechanisms of vascular calcification: lessons learned from the aorta. Arterioscler Thromb Vasc Biol. 2006;26:1423–1430. [PubMed]
89. Gaillard T, Schuster D, Osei K. Metabolic syndrome in Black people of the African diaspora: the paradox of current classification, definition and criteria. Ethn Dis . 2009;19(Suppl 2):S2–S7. [PubMed]
90. Smith MW, Patterson N, Lautenberger JA, et al. A high-density admixture map for disease gene discovery in african americans. Am J Hum Genet. 2004;74:1001–1013. [PubMed]
91. Divers J, Moossavi S, Langefeld CD, Freedman BI. Genetic admixture: a tool to identify diabetic nephropathy genes in African Americans. Ethn Dis. 2008;18:384–388. [PubMed]