There is an excess burden of ESRD in African-American, Hispanic,. Native Americans, and Asian/Pacific Islanders. Moreover, there is mounting evidence to ...
RACIAL DISPARITIES IN RENAL REPLACEMENT THERAPY Crystal Gadegbeku, MD, Michele Freeman, MD, and Lawrence Agodoa, MD Charleston, South Carolina, Inglewood, California, and Bethesda, Maryland
Renal replacement therapy (RRT)-encompassing hemodialysis, peritoneal dialysis, and kidney transplantation-provides life-sustaining treatment for the expanding end-stage renal disease (ESRD) population. There is an excess burden of ESRD in African-American, Hispanic, Native Americans, and Asian/Pacific Islanders. Moreover, there is mounting evidence to suggest that significant racial and ethnic disparities exist in RRT-including referral and initiation of dialysis, adequacy of dialysis, and anemia management-with non-white patients usually at a disadvantage. In addition, there are cultural and sociodemographic differences that lead to racial variation in the choice of ESRD modality. Lastly, in certain ethnic ESRD populations, there are a series of complex issues, from biologic to socioeconomic, which limit kidney transplantation-the treatment of choice. Despite these inequalities, which are often associated with negative outcomes, these non-white groups have better hemodialysis survival rates than white patients. It is essential to develop strategies to address the disparities in ESRD treatment among minority groups in order to minimize the differences in RRT provision and identify the factors that confer improved dialysis survival-thus improving care for all Americans with kidney disease.
Key words: end-stage renal disease * dialysis * kidney transplant + minority groups Renal replacement therapy (RRT)-encompassing hemodialysis, peritoneal dialysis, and kidney transplantation-is a life-preserving treatment for the growing number of patients suffering from end-stage renal disease (ESRD). In 1999, over 424,000 Americans received RRT.' Based on the present annual growth rate, it is expected that the ESRD population will double by 2010, with a projected annual cost of $30 billion per year.2 © 2002. From the Medical University of South Carolina, Charleston, South Carolina; the Association of Minority Nephrologists, Inglewood, California; and the National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland. Address correspondence to: Crystal Gadegbeku, MD, Assistant Professor of Medicine, Division of Nephrology, 96 Jonathan Lucas St, Charleston, SC 29425; phone (843) 792-4208; fax (843) 792-4208; or direct e-mail to gadegbek@ muscusc.edu. JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION
Minority group patients are over-represented in the ESRD population in the United States. More specifically, African Americans, Hispanics, Native Americans, Asian Americans, and Pacific Islanders are 4.0, 2.8, 1.8, 1.6, and 1.5 times more susceptible to kidney disease than white Americans, respectively. 1,3 There is growing information identifying race-related differences in the provision of RRT, which appears to be based on multiple complex factors. In this paper, we review the racial variations in RRT and discuss how the special needs of disadvantaged groups can be addressed to achieve a more effective and comprehensive system of care for patients with ESRD.
SPECIALIST REFERRAL Early referral of patients with kidney disease to a nephrologist allows the initiation of appropriate interventions to slow the rate of progression of disease and to provide optimal management of the VOL. 94, NO. 8 (SUPPL), AUGUST 2002
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comorbid conditions. In contrast, late or emergency referral is associated with three-fold higher mortality and morbidity rates, and longer, more expensive hospital stays.4'5 A retrospective analysis of insured patients in an urban teaching hospital demonstrated that non-white patients were approximately six times more likely be referred to a nephrologist in the advanced stages of renal failure.6 More specifically, non-white patients had significantly higher serum creatinine values, lower hematocrit concentrations, and were referred later compared with white patients and, therefore, received less care by a nephrologist prior to initiation of dialysis.6 In addition to delayed referral, late initiation of RRT is more common in ethnic minorities. In a cross-sectional analysis of 160,000 patients with ESRD, late initiation of RRT, even after adjustment for differences in demographic and socioeconomic factors, was 47%, 66%, and 88% more common in Hispanics, Asian Americans, and other minority races than in whites, respectively.7 In African Americans, lower levels of kidney function at initiation of dialysis appear to be closely linked to clinical, demographic and socioeconomic factors to a greater extent than in other racial groups.7,8 In general, nephrology referral and treatment are among the many aspects of medical care influenced by socioeconomic and insurance status,9-11 which tend to disproportionately affect ethnic minorities.11 Other potential contributing factors associated with inappropriately delayed nephrology-related care include physician bias,8 patient beliefs, regional practices,7 communication barriers,12 lack of patient education, and patients' lack of trust in the healthcare system.12
HEMODIALYSIS Incidence A disproportionate number of non-white patients receive hemodialysis as the treatment modality for RRT. Data from the US Renal Data System (USRDS) in 1999 revealed that African-American patients have the highest incidence of hemodialysis followed by
Native Americans, Hispanics, Asian Americans, and white patients (Fig. 1).1 46S JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION
The higher prevalence of hemodialysis (as opposed to peritoneal dialysis) in non-white ESRD patients appears to be related to multiple factors and is discussed more extensively later. With regard to the extent of care guided by a nephrologist, there are conflicting reports as to whether late referral, more common in non-white patients, increases the likelihood of hemodialysis therapy. 13-15
Vascular Access In preparation for chronic hemodialysis, an autologous arteriovenous fistula is the preferred angioaccess, over a synthetic arteriovenous graft'6 or intravenous catheter,17 owing to the lower rates of thrombosis and infection. Despite these recommendations and available outcome data, African Americans more commonly have synthetic grafts than white Americans.3,18'19 Late referral, which necessitates immediate access placement, may be one of the causes of this discrepancy.18 Furthermore, late referral is associated with an increased chance of dialysis catheter use.18-20 It is possible that more frequent use of suboptimal vascular access leads to increased access-related morbidity, inconvenience, and expense compared with non-white ESRD patients on hemodialysis.
Hemodialysis Delivery With regard to dialysis delivery, a dialysis prescribed dose less than the recommended level21 is associated with higher mortality in patients with ESRD.22 Despite clear guidelines for hemodialysis dose and frequent monitoring, the prescribed dose is more likely to be suboptimal in AfricanAmerican hemodialysis patients.23,24 The reason(s) remain unclear. Paradoxically, the survival of African Americans on hemodialysis is better than whites.25 Interestingly, the relationship between dialysis dose and mortality risk appears to be weakest in blacks.23 A better understanding of this paradox, as well as the influence of gender, may lead to improved outcomes for all patients. More immediately, there may be potential for VOL. 94, NO. 8 (SUPPL), AUGUST 2002
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further improvement in hemodialysis survival with the combination of timely referral, optimal angioaccess, and optimal dialysis delivery.
PERITONEAL DIALYSIS Incidence There is significant regional variation, ranging from 5 % to 11%, in the proportion of patients on peritoneal dialysis in the US. Overall, there has been a trend towards decreasing use, which coincides with published reports of worsening long-term outcomes in patients on peritoneal dialysis, compared with those on hemodialysis.26,27 However, studies have also shown that survival on peritoneal dialysis is better within the first 2 years of peritoneal dialysis therapy.28 After 30 months, survival on hemodialysis is better.27 However, because of differences in patient characteristics, these two modalities are difficult to compare. 1000
More recent reports suggest that survival rates among diabetic patients on peritoneal dialysis may not be different.29 With regard to racial variation in peritoneal dialysis use, whites and Asian Americans30 are more likely to be placed on peritoneal dialysis compared with African Americans3,14,15,30 and Native Americans.30 For example, in the Southeast, one study observed that African Americans were 50% less likely, compared with white Americans, to be initiated on peritoneal dialysis as an initial mode of ESRD treatment.31 The choice of peritoneal dialysis tends to be a function of education and socioeconomic status. However, these factors do not fully explain the racial discrepancy.31 Other factors such as cultural bias, body image,31 physician bias,3 and communication barriers12 may contribute to the lower rates of peritoneal dialysis among certain minority groups.
Whites
-Y- African Americans -_- Native Americans 800 -*- Asian Americans
-0- Hispanics
0
0
600
0.
5
400
200
0 1990
1993
1996
1999
Year of Incidence
Figure 1. Incidence of Dialysis Patients by Race/Ethnicity and First Modality (Adjusted for Age and Gender).3 Data from Reddan et al. 2000. JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION
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Racial Differences in Morbidity and Mortality Despite these ethnic differences in the overall use of peritoneal dialysis, mortality is higher for white compared with African-American ESRD patients.25 As in hemodialysis patients, this survival benefit occurs despite the fact that African Americans are less likely to achieve the minimum required prescribed dose in peritoneal dialysis than in hemodialysis.32 Although data are lacking for direct comparisons between other ethnic groups on peritoneal dialysis, the survival rates for Hispanic Americans are 88% at 1 year and 67% at 3 years.33 Both diabetic and non-diabetic Hispanic patients on peritoneal dialysis and hemodialysis had lower hospitalization rates than did their non-Hispanic counterparts. Peritoneal catheter complications and peritonitis were more frequent among African Americans34 and Native Americans.35 In addition, hospital days per admission are slightly higher for nonwhite than for white patients.35 The reasons for these differences in morbidity are not known. Overall, there is an overwhelming need for long-term studies to more clearly define the key factors that underlie the racial, ethnic and/or gender differences in outcomes among patients on peritoneal dialysis.
been used less aggressively to correct anemia among patients on peritoneal dialysis. rHuEPOtreated patients on peritoneal dialysis are less likely than those on hemodialysis to meet the minimum recommended a hematocrit level of at least 33%.36 Furthermore, the difference in hematocrit levels between hemodialysis and peritoneal dialysis patients has increased annually, but remained smallest among whites and greatest among African and Native Americans.36 These data suggest that physicians may not be as diligent in the management of anemia in peritoneal dialysis. In addition, it is possible that patients on peritoneal dialysis may be more reluctant to increase the self-injected rHuEPO dose or have additional visits for iron therapy compared with hemodialysis patients who are administered rHuEPO and iron by technical staff as a routine part of hemodialysis. African-American patients tend to have more severe anemia and utilize more rHuEPO.32,38 For example, in one study, African-American patients using peritoneal dialysis had significantly lower
(a) 1.6 M Whites =African Americans
. 1.4
*~1.2 1.0
ANEMIA MANAGEMENT IN ESRD Anemia is a major and serious complication of ESRD. The widespread use of recombinant human erythropoietin (rHuEPO) has dramatically improved anemia management in RRT. While the National Kidney Foundation's Disease Outcome Quality Initiative (NKF-DOQITM) recommended a hematocrit level of at least 33%, this level was achieved by only 8% of patients on hemodialysis in 1990; this figure rose to 67% in 1998, which corresponded to a 10% reduction in both first- and second-year death rates.12 In both AfricanAmerican and white patients, the mortality and hospitalization risk decreased in a similar pattern when the recommended hematocrit level of 33% is achieved (Fig. 2).36,37 Despite the current guidelines, rHuEPO has 48S JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION
0.8
