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Indigenous people in Australia, Canada, New Zealand and the United States are less likely to receive renal transplantation

2009; Elsevier BV; Volume: 76; Issue: 6 Linguagem: Inglês

10.1038/ki.2009.236

1523-1755

Karen Yeates, Alan Cass, Thomas D. Sequist, Stephen P. McDonald, Meg Jardine, Lilyanna Trpeski, John Z. Ayanian,

Organ Transplantation Techniques and Outcomes

In Australia, Canada, New Zealand, and the United States indigenous people have high rates of chronic kidney disease but poor access to effective therapies. To more fully define these issues, we compared the demographics of renal transplantation of indigenous patients in these 4 countries. Data encompassing 312,507 indigenous and white patients (18–64 years of age) who initiated dialysis within an 11-year period ending in 2005 were obtained from each country's end-stage kidney disease registry. By the study's end, 88,173 patients had received a renal transplant and 130,261 had died without receiving such. Compared with white patients, the adjusted likelihood of receiving a transplant for indigenous patients was significantly lower in Australia (hazard ratio (HR) 0.23), Canada (HR 0.34), New Zealand (HR 0.23), and the United States (HR 0.44). In all four countries, indigenous patients had significantly longer overall median waiting times compared to white patients. Our study shows that despite marked differences in health care delivery systems, indigenous patients are less likely than white patients to receive a renal transplant in these countries. Understanding and addressing barriers to renal transplantation of indigenous patients remains an important concern. In Australia, Canada, New Zealand, and the United States indigenous people have high rates of chronic kidney disease but poor access to effective therapies. To more fully define these issues, we compared the demographics of renal transplantation of indigenous patients in these 4 countries. Data encompassing 312,507 indigenous and white patients (18–64 years of age) who initiated dialysis within an 11-year period ending in 2005 were obtained from each country's end-stage kidney disease registry. By the study's end, 88,173 patients had received a renal transplant and 130,261 had died without receiving such. Compared with white patients, the adjusted likelihood of receiving a transplant for indigenous patients was significantly lower in Australia (hazard ratio (HR) 0.23), Canada (HR 0.34), New Zealand (HR 0.23), and the United States (HR 0.44). In all four countries, indigenous patients had significantly longer overall median waiting times compared to white patients. Our study shows that despite marked differences in health care delivery systems, indigenous patients are less likely than white patients to receive a renal transplant in these countries. Understanding and addressing barriers to renal transplantation of indigenous patients remains an important concern. In Australia, Canada, New Zealand, and the United States, indigenous people experience substantially worse health outcomes than non-indigenous people.1.Bramley D. Hebert P. Jackson R. et al.Indigenous disparities in disease-specific mortality, a cross-country comparison.NZ Med J. 2004; 117: U1215PubMed Google Scholar Over the last two decades, the prevalence of chronic disease among indigenous people has risen dramatically, with a well documented excess burden of diabetes, heart disease, and kidney disease.1.Bramley D. Hebert P. Jackson R. et al.Indigenous disparities in disease-specific mortality, a cross-country comparison.NZ Med J. 2004; 117: U1215PubMed Google Scholar, 2.McDonald S.P. Russ G.R. Burden of end-stage renal disease among Indigenous peoples in Australia and New Zealand.Kidney Int Suppl. 2003; 83: S123-S127Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar, 3.Dyck R.F. Mechanisms of renal disease in Indigenous populations: influences at work in Canada's Indigenous people.Nephrology. 2001; 6: 3-7Crossref Scopus (28) Google Scholar, 4.Narva A.S. The spectrum of kidney disease in American Indians.Kidney Int Suppl. 2003; 83: S3-S7Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar, 5.Canadian Institute for Health Information (CIHI) Canadian Organ Replacement Register 2001 report. Volume 1: Dialysis and renal transplantation (includes data 1981–1999). CIHI, Ottawa2001Google Scholar In Australia, New Zealand, and Canada, indigenous people experience more than twice the prevalence of end-stage kidney disease (ESKD) than whites. Similarly, in the United States, American Indians and Alaskan Natives have a 2.5 percent higher prevalence of ESKD as compared with white Americans.1.Bramley D. Hebert P. Jackson R. et al.Indigenous disparities in disease-specific mortality, a cross-country comparison.NZ Med J. 2004; 117: U1215PubMed Google Scholar, 2.McDonald S.P. Russ G.R. Burden of end-stage renal disease among Indigenous peoples in Australia and New Zealand.Kidney Int Suppl. 2003; 83: S123-S127Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar, 3.Dyck R.F. Mechanisms of renal disease in Indigenous populations: influences at work in Canada's Indigenous people.Nephrology. 2001; 6: 3-7Crossref Scopus (28) Google Scholar, 4.Narva A.S. The spectrum of kidney disease in American Indians.Kidney Int Suppl. 2003; 83: S3-S7Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar, 5.Canadian Institute for Health Information (CIHI) Canadian Organ Replacement Register 2001 report. Volume 1: Dialysis and renal transplantation (includes data 1981–1999). CIHI, Ottawa2001Google Scholar, 6.Scavini M. Stidley C.A. Paine S.S. et al.The burden of chronic kidney disease among the Zuni Indians: the Zuni Kidney Project.Clin J Am Soc Neph. 2007; 2: 509-516Crossref PubMed Scopus (21) Google Scholar, 7.Dyck R.F. Mechanisms of renal disease in indigenous populations: influences at work in Canadian indigenous peoples.Nephrology. 2001; 6: 3-7Crossref Scopus (36) Google Scholar, 8.McDonald S.P. Russ G.R. Current incidence, treatment patterns and outcome of end-stage renal disease among indigenous groups in Australia and New Zealand.Nephrology. 2003; 8: 42-48Crossref PubMed Scopus (78) Google Scholar Systematic differences in rates of utilization of primary care and preventive services contribute to poorer outcomes.9.Shah B.R. Gunraj N. Hux J.G. Markers of access to and quality of primary care for Aboriginal people in Ontario, Canada.Am J Public Health. 2003; 93: 798-801Crossref PubMed Scopus (91) Google Scholar Indigenous patients also have unequal access to diagnostic and therapeutic procedures that are used to treat chronic diseases, such as angiography, percutaneous coronary interventions, and coronary artery bypass grafting for coronary artery disease, when compared with non-indigenous patients.10.Coorey M.D. Walsh W.F. Rates of percutaneous coronary interventions and bypass surgery after acute myocardial infarction in Indigenous patients.Med J Aust. 2005; 182: 507-512PubMed Google Scholar, 11.Cunningham J. Diagnostic and therapeutic procedures among Australian hospital patients identified as Indigenous.Med J Aust. 2002; 176: 58-62PubMed Google Scholar, 12.Sequist T.D. Zaslavsky A.M. Galloway J.M. et al.Cardiac procedure use following acute myocardial infarction among American Indians.Am Heart J. 2006; 151: 909-914Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar Kidney transplantation is considered as the optimal treatment for most non-elderly patients with ESKD, conferring a significant survival advantage and improvement in quality of life over dialysis therapy.13.Wolfe R.A. Ashby V.B. Milford E.L. et al.Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant.N Engl J Med. 1999; 341: 1725-1730Crossref PubMed Scopus (3576) Google Scholar,14.Laupacis A. Keown P. Pus N. et al.A study of the quality of life and cost-utility of renal transplantation.Kidney Int. 1996; 50: 235-242Abstract Full Text PDF PubMed Scopus (837) Google Scholar However, analyses from individual countries, some regional in scope and others with limited adjustment for confounding factors, have shown that indigenous patients have low rates of kidney transplantation.15.Sequist T.D. Narva A.S. Stiles S.K. et al.Access to renal transplantation among American Indians and Hispanics.Am J Kidney Dis. 2004; 44: 344-352Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar, 16.Yeates K.E. Schaubel D.E. Cass A. et al.Access to renal transplantation for minority patients with ESRD in Canada.Am J Kidney Dis. 2004; 44: 1083-1089Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar, 17.Cass A. Cunningham J. Snelling P. et al.Renal transplantation for Indigenous Australians: identifying the barriers to equitable access.Ethn Health. 2003; 8: 111-119Crossref PubMed Scopus (46) Google Scholar, 18.Tonelli M. Hemmelgarn B. Manns B.J. et al.Death and renal transplantation among Aboriginal people undergoing dialysis.CMAJ. 2004; 17: 577-582Crossref Scopus (65) Google Scholar In this study, we compared renal transplant utilization by indigenous patients across four countries – Australia, Canada, New Zealand, and the United States – that have distinctly different health care systems. Our study had two primary objectives: (1) To assess transplantation rates (overall, and from deceased and living donors) among indigenous and white patients while controlling for comparable demographic and clinical variables across all four countries; and (2) to compare median transplant waiting times (by donor type) among indigenous and white patients in each country. The cohort consisted of 312,507 patients from ages 18 to 64 years, including 9837 from Australia, 17,986 from Canada, 2771 from New Zealand, and 281,913 from the United States. By 31 December 2006, 28% of the cohort (88,173 patients) had received a renal transplant, and 41.6% (130,261) had died without receiving a transplant. The characteristics of indigenous and white patients beginning maintenance dialysis in each country are depicted in Table 1. Indigenous patients represented 18% of the study cohort in Australia, 9% in Canada, 56% in New Zealand, and 3% in the United States. With the exception of New Zealand, there were significantly fewer men and more women in the indigenous cohorts when compared with the non-indigenous cohorts. In all four countries, indigenous patients were significantly more likely to have a body mass index (BMI) greater than 30 kg/m2 and to have diabetes than whites. There were significantly higher rates of ischemic heart disease among indigenous patients in Australia and New Zealand, and higher rates of peripheral vascular disease among indigenous patients in all four countries. The rates of chronic lung disease and smoking were significantly lower in indigenous patients in the United States, and higher in Australia and New Zealand. Indigenous patients were significantly more likely to smoke in Australia, Canada, and New Zealand, but less likely to smoke in the United States.Table 1Demographic and clinical characteristics of indigenous and white patients in Australia, Canada, New Zealand, and the United StatesCountryAustraliaCanadaNew ZealandUnited StatesWhiteIndigenousWhiteIndigenousWhiteIndigenousWhiteIndigenousN (%)8058 (81.9)1779 (18.1)16,336 (90.8)1650 (9.2)1216 (43.9)1555 (56.1)274,125 (97.2)7788 (2.8)Age (N (%)) 18–29 years819 (10.6)114 (6.4)**P≤0.01.1109 (6.8)151 (9.2)**P≤0.01.119 (9.8)108 (6.9)**P≤0.01.16,870 (6.1)404 (5.2)**P≤0.01. 30–44 years1987 (24.7)522 (29.3)**P≤0.01.3817 (23.4)346 (20.9)**P≤0.01.319 (26.2)282 (18.1)**P≤0.01.57,454 (21.0)1584 (20.3)**P≤0.01. 45–65 years5252 (64.7)1143 (62.7)**P≤0.01.11,410 (69.8)1153 (69.9)778 (63.9)1165 (74.9)**P≤0.01.199,801 (72.9)5800 (74.5)**P≤0.01.Gender (N (%)) Male4919 (61.0)824 (46.3)**P≤0.01.10,136 (62.1)806 (48.9)**P≤0.01.740 (59.8)873 (55.2)*P<0.05.157,828 (57.6)3846 (49.4)**P≤0.01. Female3139 (38.9)955 (53.7)**P≤0.01.6200 (37.9)844 (51.1)**P≤0.01.476 (39.1)682 (43.8)*P<0.05.116,295 (42.4)3942 (50.6)**P≤0.01.Body mass index (N (%)) <18.5 mg/m2317 (3.9)92 (5.2)**P≤0.01.538 (3.7)30 (2.1)**P≤0.01.37 (3.0)13 (0.8)**P≤0.01.12,904 (5.2)266 (3.7)**P≤0.01. 18.5–24.9 mg/m23276 (40.9)599 (33.9)**P≤0.01.5548 (38.4)405 (27.7)**P≤0.01.536 (44.4)269 (17.5)**P≤0.01.85,028 (34.1)2101 (29.0)**P≤0.01. 25–29.9 mg/m22555 (31.9)520 (29.5)**P≤0.01.4309 (29.9)511 (35.0)**P≤0.01.394 (32.6)493 (32.0)**P≤0.01.69,372 (27.9)2247 (31.1)**P≤0.01. ≥30 mg/m21849 (23.1)522 (31.3)**P≤0.01.4038 (27.9)514 (35.2)**P≤0.01.240 (19.9)763 (49.6)**P≤0.01.81,698 (32.8)2616 (36.2)**P≤0.01.Diabetes (N (%))2255 (27.9)1293 (72.7)**P≤0.01.5840 (35.8)1011 (61.3)**P≤0.01.278 (22.9)1072 (68.9)**P≤0.01.122,823 (44.8)5122 (65.8)**P≤0.01. Cerebrovascular disease (N (%))509 (6.3)147 (8.3)*P<0.05.1272 (8.6)147 (9.5)74 (6.1)117 (7.5)16,541 (6.0)481 (6.2) Ischemic heart disease (N (%))1514 (18.9)429 (24.1)**P≤0.01.2586 (15.7)256 (15.5)190 (15.6)329 (21.2)**P≤0.01.54,134 (19.7)1414 (18.2)**P≤0.01. Peripheral vascular disease (N (%))1081 (13.4)315 (17.7)**P≤0.01.2819 (17.3)397 (24.1)**P≤0.01.144 (11.8)288 (18.5)**P≤0.01.32,240 (11.8)1235 (15.9)**P≤0.01. Chronic lung disease (N (%))866 (10.7)253 (14.2)**P≤0.01.1225 (7.5)106 (6.4)103 (8.5)276 (17.8)**P≤0.01.13,345 (4.9)217 (2.8)**P≤0.01. Current smoker (N (%))1272 (15.8)472 (26.5)**P≤0.01.2993 (18.3)368 (22.3)**P≤0.01.197 (16.2)384 (24.7)**P≤0.01.20,139 (7.3)450 (5.8)**P≤0.01.* P<0.05.** P≤0.01. Open table in a new tab In all four countries, indigenous patients had significantly lower crude transplant rates per 100 person-years than white patients (Table 2). Unadjusted transplant rates for indigenous recipients were different among the countries (P<0.01). Disparities in access to transplantation were observed from both living and deceased donor sources. The proportion of transplants from living donors was lower among indigenous than among white transplant recipients in Australia (21.9 vs 39.2%), New Zealand (34.2 vs 42.1%), and the United States (36.8 vs 44.2%). In contrast, the proportion of transplants from living donors was slightly higher for indigenous than for white recipients in Canada (39.5 vs 37.7%) (Table 2).Table 2Crude transplant ratesaRates are calculated per 100 patient-years. for indigenous and white patients in Australia, Canada, New Zealand, and the United StatesCountryEthnicityAll transplantsDeceased donorLiving donorLiving donor sourceUnadjusted rates (95% CI)Unadjusted rates (95% CI)Unadjusted rates (95% CI)(% of total)AustraliaIndigenous3.3 (2.8–3.8)2.6 (2.2–3.0)0.7 (0.5–0.9)21.9White14.8 (14.3–15.3)8.9 (8.6–9.4)5.8 (5.4–6.0)39.2CanadaIndigenous3.8 (3.3–4.3)2.3 (1.8–2.6)1.5 (1.2–1.8)39.5White11.8 (11.5–12.1)7.2 (6.9–7.4)4.6 (4.4–4.8)37.7New ZealandIndigenous2.8 (2.4–3.2)1.8 (1.5–2.2)0.9 (0.7–1.2)34.2White19.5 (17.8–21.0)11.3 (10.1–12.4)8.2 (7.1–9.4)42.1United StatesIndigenous4.1 (3.8–4.3)2.6 (2.4–2.8)1.4 (1.3–1.6)36.8White10.4 (10.3–10.4)5.8 (5.7–5.8)4.5 (4.4–4.6)44.2CI, confidence interval.a Rates are calculated per 100 patient-years. Open table in a new tab CI, confidence interval. Table 3 displays unadjusted and adjusted hazard ratios (HRs) for renal transplantation overall and by donor type for indigenous patients relative to white patients. Unadjusted HRs for renal transplantation overall were 0.23 (CI 0.19–0.28) in Australia, 0.33 (CI 0.26–0.36) in Canada, 0.15 (CI 0.13–0.19) in New Zealand, and 0.42 (CI 0.36–0.42) in the United States. Age, sex, and comorbid conditions explained only a small portion of these disparities, as adjustment for these variables changed the respective HR in each country only minimally. In each country, disparities in access were similar for both deceased and living donor transplants (Table 3).Table 3Unadjusted and adjusted hazard ratios for indigenous patients relative to white patients in Australia, Canada, New Zealand, and the United StatesCountryAll transplantsDeceased donorLiving donorUnadjusted HR (95% CI)AdjustedaAdjusted for age, sex, primary cause of end-stage kidney disease, year of diagnosis, comorbidities (diabetes, cerebrovascular disease, ischemic heart disease, peripheral vascular disease, chronic lung disease, and current smoking), and region. HR (95% CI)Unadjusted HR (95% CI)AdjustedaAdjusted for age, sex, primary cause of end-stage kidney disease, year of diagnosis, comorbidities (diabetes, cerebrovascular disease, ischemic heart disease, peripheral vascular disease, chronic lung disease, and current smoking), and region. HR (95% CI)Unadjusted HR (95% CI)AdjustedaAdjusted for age, sex, primary cause of end-stage kidney disease, year of diagnosis, comorbidities (diabetes, cerebrovascular disease, ischemic heart disease, peripheral vascular disease, chronic lung disease, and current smoking), and region. HR (95% CI)Australia0.23 (0.20–0.26)0.23 (0.19–0.27)0.29 (0.24–0.33)0.32 (0.27–0.37)0.15 (0.10–0.19)0.18 (0.13–025)Canada0.33 (0.28–0.37)0.34 (0.29–0.40)0.31 (0.26–0.37)0.31 (0.26–0.37)0.35 (0.28–0.43)0.39 (0.30–0.49)New Zealand0.15 (0.12–0.18)0.23 (0.19–0.28)0.15 (0.13–0.18)0.22 (0.17–0.28)0.14 (0.10–0.18)0.26 (0.18–0.37)United States0.42 (0.40–0.45)0.44 (0.42–0.47)0.46 (0.43–0.49)0.49 (0.45–0.53)0.37 (0.33–0.41)0.40 (0.36–0.44)CI, confidence interval; HR, hazard ratio.a Adjusted for age, sex, primary cause of end-stage kidney disease, year of diagnosis, comorbidities (diabetes, cerebrovascular disease, ischemic heart disease, peripheral vascular disease, chronic lung disease, and current smoking), and region. Open table in a new tab CI, confidence interval; HR, hazard ratio. Table 4 presents median waiting times overall and by donor type for indigenous compared with white patients. In all four countries, indigenous patients had significantly longer overall median waiting times (P<0.01) when compared with white patients. Indigenous recipients waited longest for deceased donor transplants in the United States (3 years) and shortest in Canada (2.5 years). Waiting times for living donor transplants were significantly longer for indigenous compared with white patients in Australia (2.7 vs 0.7 years; P<0.01), Canada (1.6 vs 0.8 years; P<0.01), New Zealand (1.2 vs 0.6 years; P=0.01), and the United States (1.2 vs 0.6 years; P<0.01).Table 4Median renal transplant wait times in years by country among transplant recipientsCountryEthnicityAll transplantsDeceased donorLiving donorMedian (years)Interquartile rangeMedian (years)Interquartile rangeMedian (years)Interquartile rangeAustraliaWhite1.50.6–2.92.11.1–3.50.70.1–1.7Indigenous2.41.3–3.92.61.5–3.62.71.8–4.3CanadaWhite1.50.6–2.71.91.0.3.30.80.2–1.6Indigenous2.11.2–3.52.51.5–3.91.60.9–2.6New ZealandWhite1.20.4–2.41.70.9–2.90.60.0–1.6Indigenous2.21.2–3.62.71.9–4.21.20.3–2.2United StatesWhite1.10.3–2.41.80.8–3.20.60.0–1.3Indigenous2.11.1–3.83.01.6–4.41.20.5–2.0 Open table in a new tab The cumulative incidence curves for time to first renal transplant (in years) for indigenous and white patients in each country are displayed in Figure 1. Indigenous patients in all four countries had similar curves showing lower cumulative incidence of renal transplantation when compared with whites. White patients in the United States had the lowest cumulative incidence of first renal transplants overall, followed by Canada, Australia, and New Zealand, respectively. To our knowledge, this study is the first multinational evaluation of indigenous access to renal transplantation using similar methods to adjust for comparable variables from national renal registries over identical periods. Despite indigenous populations in each country bearing a significantly heavier burden of ESKD than whites, indigenous people on dialysis are undergoing renal transplantation at less than half the rate of white patients in their respective countries. Notwithstanding substantial differences in the health care systems, renal transplant programs and indigenous models of health care delivery in each country, the disparities in renal transplant rates for indigenous people are strikingly similar in magnitude across all four countries. Our study provides several important insights regarding access to renal transplantation in the four countries studied. First, the disparity in access to transplantation for indigenous patients in all four countries is significant for both deceased and living donor kidneys. Second, access to a first renal transplant for whites is poorest in the United States, followed by Canada, Australia, and New Zealand, respectively, particularly for deceased donor kidneys. As a result, the magnitude of disparity observed for indigenous patients, relative to white patients, between the countries is largely driven by the differences in white access to renal transplantation within each country. Hence, in the United States, utilization of renal transplants looks relatively better for Native Americans in comparison with the other countries studied. This is because of the low overall renal transplant rates among white Americans in comparison with Australia, Canada, and New Zealand. Third, access to living donor kidneys is relatively better for indigenous patients in Canada and the United States than in Australia and New Zealand. Disparities in living donor transplantation are concerning because this option is an increasingly important determinant of transplant access in the context of a global shortage of deceased donor kidneys. Within indigenous communities, awareness of living donor transplants as a treatment option, and the medical suitability of relatives and community members for donation are key issues to be addressed. A number of potential mediators may contribute to low indigenous transplant rates, including language barriers, patient preferences, health practitioners' attitudes,19.Cass A. Cunningham J. Anderson K. et al.Decision-making about suitability for kidney transplantation: results of a national survey of Australian nephrologists.Nephrology (Carlton). 2007; 12: 299-304Crossref PubMed Scopus (20) Google Scholar and the lack of culturally appropriate patient education programs. However, evidence regarding the relative importance of these factors remains scant. To our knowledge, culturally appropriate educational materials regarding kidney transplantation, specifically targeted to preferred ways of communicating and levels of health literacy of indigenous patients, have not been developed and implemented. Geographical remoteness has also been suggested as a factor associated with lower transplantation rates, but the evidence on this point is mixed.20.Axelrod D.A. Guidinger M.K. Finlayson S. et al.Rates of solid-organ wait-listing, transplantation, and survival among residents of rural and urban areas.JAMA. 2008; 299: 202-207Crossref PubMed Scopus (151) Google Scholar,21.Tonelli M. Klarenbach S. Manns B. Alberta Kidney Disease Network et al.Residence location and likelihood of kidney transplantation.CMAJ. 2006; 175: 478-482Crossref PubMed Scopus (55) Google Scholar Other potential barriers for indigenous patients include delayed referral for transplant evaluation22.Cass A. Cunningham J. Snelling P. et al.Late referral to a nephrologist reduces access to renal transplantation.Am J Kidney Dis. 2003; 42: 1043-1049Abstract Full Text Full Text PDF PubMed Scopus (99) Google Scholar,23.Winkelmayer W.C. Glynn R.J. Levin R. et al.Late nephrologist referral and access to renal transplantation.Transplantation. 2002; 3: 1918-1923Crossref Scopus (57) Google Scholar and delays from initial referral to wait-listing,15.Sequist T.D. Narva A.S. Stiles S.K. et al.Access to renal transplantation among American Indians and Hispanics.Am J Kidney Dis. 2004; 44: 344-352Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar, 17.Cass A. Cunningham J. Snelling P. et al.Renal transplantation for Indigenous Australians: identifying the barriers to equitable access.Ethn Health. 2003; 8: 111-119Crossref PubMed Scopus (46) Google Scholar, 24.Tonelli M. Hemmelgarn B. Gill J.S. Alberta Kidney Disease Network et al.Wait-listing for kidney transplantation among Aboriginal hemodialysis patients.Am J Kidney Dis. 2005; 46: 1117-1123Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar as reflected in the near absence of preemptive transplants among indigenous patients in our study. All the countries studied have their own particular renal transplant organ allocation systems. In general, however, organ allocation among these systems is prioritized similarly by patient waiting time with immune matching carrying relatively less weight. Once patients have been successfully wait-listed, transplant allocation algorithms that favor higher levels of HLA-matching above waiting time will reduce access for patients from ethnic minorities, as deceased donors kidneys are predominantly drawn from the majority white population.25.Delmonico F.L. Milford E.L. Goguen J. et al.A novel united network for organ sharing region kidney allocation plan improves transplant access for minority candidates.Transplantation. 1999; 68: 1875-1879Crossref PubMed Scopus (14) Google Scholar,26.Leffell M.S. Zachary A.A. The national impact of the 1995 changes to the UNOS renal allocation system. United Network for Organ Sharing.Clin J Transplant. 1999; 13: 287-295Crossref PubMed Scopus (24) Google Scholar In addition, institutional bias or racism may impede indigenous patients' access to renal transplantation. People with complex, chronic diseases, such as kidney disease, must negotiate often fragmented health care systems to access necessary care.27.Ayanian J.Z. Determinants of racial and ethnic disparities in surgical care.World J Surg. 2008; 32: 509-515Crossref PubMed Scopus (32) Google Scholar Among the four countries studied, the Indian Health Service of the United States provides the most comprehensive indigenous health care system, and it also funds a substantial component of services managed by Indian tribes. Nonetheless, the presence of the Indian Health Service and tribal health councils in the United States is not associated with substantially better access to renal transplantation for American Indians and Alaskan Natives, probably because these organizations are mainly focused on primary and secondary care, and often face restricted access to tertiary services such as renal transplantation and major cardiac procedures.12.Sequist T.D. Zaslavsky A.M. Galloway J.M. et al.Cardiac procedure use following acute myocardial infarction among American Indians.Am Heart J. 2006; 151: 909-914Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar,15.Sequist T.D. Narva A.S. Stiles S.K. et al.Access to renal transplantation among American Indians and Hispanics.Am J Kidney Dis. 2004; 44: 344-352Abstract Full Text Full Text PDF PubMed Scopus (100) Google Scholar Australia, Canada, and New Zealand have federally managed indigenous health agencies, and each of these countries has developed some community-controlled health services to improve access for indigenous patients. As in the United States, however, renal transplantation is a highly specialized procedure provided in tertiary centers that are not focused on indigenous patients. Therefore, communication across indigenous and non-indigenous health services is crucial to support indigenous patients' access to renal transplantation. Our study has several strengths and limitations. Strengths of our study include the large inclusive cohorts of patients and the consistent adjustment for relevant clinical variables across the four countries. However, we were not able to verify the accuracy of indigenous designations or determine precisely how much time indigenous patients spent on transplant waiting lists (in both active and inactive status categories). In addition, we did not have access to accurate information regarding residence location of study patients in all registry data sets. This would have allowed us to address the possibility that a relationship exists between rural residence location and racial identity (indigenous or not) that impacts on renal transplant utilization in our study groups. This would have considerably strengthened the study. Lastly, we were unable to obtain data regarding clinical characteristics, such as HLA matching, from all registries, which would provide useful information for further analyses relating to organ allocation algorithms. Substantial disparities in access to renal transplantation persist for indigenous people with ESKD across the diverse health care systems of Australia, Canada, New Zealand, and the United States. These findings suggest that reduced access may be strongly influenced by social determinants, operating beyond the confines of the respective health systems. Poverty and lower levels of educational attainment have been shown to reduce engagement in health care and to disproportionately affect indigenous populations. Without knowledge of barriers within and beyond health systems, success in improving access to renal transplantation, and other effective medical and surgical services for indigenous people will remain elusive. We analyzed data from the respective national ESKD registries, including the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA),28.MacDonald S. ANZDATA Registry 2003. Australia and New Zealand Dialysis and Transplant Registry, Adelaide2003Google Scholar Canadian Organ Replacement Register (CORR)5.Canadian Institute for Health Information (CIHI) Canadian Organ Replacement Register 2001 report. Volume 1: Dialysis and renal transplantation (includes data 1981–1999). CIHI, Ottawa2001Google Scholar of the Canadian Institute for Health Information, and the United States Renal Data System (USRDS).29.US Renal Data System: 2005 Annual Data Report Atlas of End-Stage Renal Disease in the United States. National Institutes of Health, Bethesda2005Google Scholar ANZDATA and CORR are voluntary registries that seek participation of all renal units providing dialysis and transplant services. ANZDATA includes essentially all patients with ESKD in Australia and New Zealand, whereas CORR includes over 80% of such patients in Canada. The USRDS has included all patients with ESKD in the United States since May 1995, because the Medicare End-Stage Renal Disease Program requires a Medicare Evidence form to be submitted for all patients regardless of their insurance and eligibility status. A complete de-identified dataset of requested variables was acquired from each of the respective renal registries, and analyzed at the Canadian Institute for Health Information in Toronto, Canada. The study protocol was approved by the Research Ethics Board of Queen's University, the Human Studies Committee of Harvard Medical School and the Ethics Committee of the Sydney South Western Area Health Service in Sydney, Australia. We examined data for all indigenous patients in Australia, Canada, New Zealand, and the United States who initiated maintenance dialysis for ESKD from 1 January 1995 through to 31 December 2005. Indigenous people were identified as Aboriginal Australians and Torres Strait Islanders in Australia; Maori, Samoans, Tongans, Pacific People, and Cook Islanders in New Zealand; Aboriginal people (including First Nations, Métis, and Inuit) in Canada; and American Indians and Alaska Natives in the United States. The majority population (termed 'white' in the current analysis) was designated 'white', 'Caucasian', or 'Caucasoid' in individual registries. Approximately 10% of patients in each country were missing race/ethnicity data and were therefore excluded, as were patients of other racial groups. We restricted our analysis to adult patients aged 18–64 years at initiation of dialysis, because older patients are less likely to be clinically appropriate for renal transplantation. Variables extracted from each national renal registry included patients' age, sex, primary renal diagnosis, comorbid conditions, height, weight, smoking status, and region of initial dialysis treatment. Race is reported to each registry by participating clinical facilities, on the basis of information recorded in patients' medical records. BMI (kg/m2) was categorized according to World Health Organization criteria as underweight (BMI <18.5 kg/m2), normal weight (BMI 18.5–24.9 kg/m2), overweight (BMI 25.0–29.9 kg/m2), and obese (BMI ≥30.0 kg/m2).30www.cdc.gov/nccdphp/dnpa/bmi/index.htm. Last accessed on 29 October 2008Google Scholar Comorbid conditions recorded by each registry at the onset of ESKD included diabetes mellitus, ischemic heart disease (myocardial infarction or angina), peripheral vascular disease, cerebrovascular disease, chronic obstructive pulmonary disease, and current smoking. The demographic and clinical characteristics of indigenous and white patients were compared within each country using the Pearson's χ2-test. The unadjusted transplant rates per 100 patient-years of treatment were calculated for indigenous and white patients in each country, with renal transplantation defined as a first living or deceased donor transplant. Crude transplant rates were compared between countries (with the United States as the reference group) using a Poisson model. Patients were followed up to the date of first renal transplant or to 31 December 2006 for Australia, Canada, and New Zealand with the exception of the United States, wherein follow-up was until 30 September 2006. Patients were censored at the date of death. Cox proportional hazards regression models were used to compare the adjusted likelihood of renal transplantation from living and/or deceased donors for indigenous patients relative to white patients in each country, controlling for the demographic and clinical variables listed above. Median transplant wait times were calculated overall and by donor type from the initiation of renal replacement therapy to renal transplantation for indigenous and white patients in each country using the Wilcoxon rank-sum test. Cumulative incidence curves for renal transplantation were produced for indigenous vs white patients in each of the four countries. SAS statistical software version 8.2 (Cary, North Carolina) was used for all analyses. Two-tailed P-values or 95% confidence intervals are presented for all statistical comparisons of indigenous and white patients. KEY is supported by a Biomedical Scholarship from the Kidney Foundation of Canada. AC was supported by a Harkness Fellowship from the Commonwealth Fund and receives ongoing support through a Senior Research Fellowship from the Australian National Health and Medical Research Council. TDS is supported by a Harold Amos Medical Faculty Development Award from the Robert Wood Johnson Foundation. MJJ is supported by a Clinical Epidemiology Training Scholarship from the National Health & Medical Research Council Centre of Clinical Research Excellence in Renal Medicine. JZA was supported by an Australia–Harvard Fellowship from the Harvard Club of Australia Foundation and by a Visiting Professorial Fellowship from the University of Sydney. We are grateful to the Australia and New Zealand Dialysis and Transplant Registry, The Canadian Organ Replacement Register (CORR), and the United States Renal Data System for providing data for this analysis, and to the CORR for supporting the statistical analysis. The CORR is managed by the Canadian Institute for Health Information.