Access to Kidney Transplantation among Patients Insured by the United States Department of Veterans Affairs

CLINICAL RESEARCH www.jasn.org Access to Kidney Transplantation among Patients Insured by the United States Department of Veterans Affairs John S. Gill,* Syed Hussain, Caren Rose,* Sundaram Hariharan, and Marcello Tonelli *Division of Nephrology, University of British Columbia, Vancouver, British Columbia, Canada; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts, and Centre for Health Evaluation Outcomes Sciences, Universtiy of British Columbia, Vancouver, British Columbia, Canada; Medical College of Wisconsin, Milwaukee, Wisconsin; and Division of Critical Care Medicine, University of Alberta, and Institute of Health Economics, Edmonton, Alberta, Canada ABSTRACT Ensuring equal access to kidney transplantation is of paramount importance. Veterans that receive care from the Department of Veteran Affairs (VA) must complete a complex process to be placed on the transplant wait-list, and only four VA hospitals in the United States transplant kidneys. This unique system may cause VA patients to wait longer for kidney transplants than other patients. We compared the time to transplantation among ESRD patients insured by the VA to those insured by private insurance or Medicare/Medicaid. Of 7395 veterans studied, 9.3% received transplants, compared to 35,450 of 144,651 (24.5%) patients with private insurance and 36,150 of 357,345 (10.1%) patients with Medicare/ Medicaid insurance (P 0.0001). We found that both VA-insured and Medicare/Medicaid-insured patients were approximately 35% less likely to receive transplants than patients with private insurance (hazard ratio [HR] 0.65; 95% CI 0.60 to 0.70; P 0.0001). Most of this difference was explained by the fact that VA patients were less likely to be placed on the wait-list (HR 0.71; 95% CI 0.67 to 0.76), but even listed VA patients received transplants less frequently than those insured privately (HR 0.89; 95% CI 0.82 to 0.96). Interestingly, VA patients with supplemental private insurance had the same likelihood of transplantation as non-va patients with private insurance. We conclude that VA-insured patients are less likely to receive transplants than privately insured patients, and that further studies are needed to identify the reasons for this disparity. J Am Soc Nephrol 18: 2592 2599, 2007. doi: 10.1681/ASN.2007010050 Kidney transplant recipients live longer, have improved quality of life, and consume fewer health care resources than patients who are treated with dialysis. 1 3 The demand for kidney transplantation far exceeds the supply of available organs. 4 Under these conditions, ensuring equitable access to kidney transplantation is of fundamental importance. Before 1972, the Department of Veterans Affairs (VA) or private insurance paid for dialysis and transplantation. Resources for patients who had ESRD and did not have VA benefits or private insurance were scarce; therefore, many of these patients died of preventable complications of renal failure. In 1972, Congress amended the Social Security Act to allow dialysis and renal transplantation to be covered by Medicare. Although sociodemographic factors are known to influence access to kidney transplantation, few studies have examined access to transplantation among patients with dif- Received January 14, 2007. Accepted May 29, 2007. Published online ahead of print. Publication date available at www.jasn.org. Correspondence: Dr. John S. Gill, St. Paul s Hospital, Providence Building Ward 6a, 1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6. Phone: 604-806-9048; Fax: 604-806-8076; E-mail: jgill@providencehealth.bc.ca Copyright 2007 by the American Society of Nephrology 2592 ISSN : 1046-6673/1809-2592 J Am Soc Nephrol 18: 2592 2599, 2007

www.jasn.org CLINICAL RESEARCH ferent types of medical insurance. Medicare-insured patients are less likely to be placed on the waiting list for transplantation before initiation of dialysis and less likely to have transplantation as their first form of ESRD treatment than patients with private insurance. 5,6 Eligible patients who wish to receive a kidney transplant through the VA must successfully complete a centralized assessment that is potentially more complex than the corresponding system for patients who are assessed for transplantation outside the VA. 7 For example, all referrals for transplantation through the VA are screened at a central facility in Washington, DC (rather than at the patient s local transplant center), and patients who use the VA must receive kidney transplants at one of four VA transplant centers (as opposed to the approximately 250 transplant centers that potentially are available to non-va users). We hypothesized that the process of accessing transplantation through the VA would result in longer waiting times than in patients who accessed transplantation outside the VA. RESULTS Compared with the 509,391 study patients, the 27,711 excluded patients were younger (49.7 12.9 versus 53.7 12.1 yr; P 0.0001), more likely to be male (55.4 versus 54.7%; P 0.02), more likely to be of white race (67.6 versus 57.7%; P 0.0001), and less likely to have diabetes as the cause of ESRD (25.6 versus 48.1%; P 0.0001). Table 1 compares the characteristics of patients with various types of medical insurance. Patients with VA insurance were older, predominantly male, and more likely to have diabetes as the cause of ESRD; had a higher burden of comorbid disease; and were more likely to smoke, be unable to ambulate, and be unemployed. Figure 1 shows that patients with VA insurance and Medicare/Medicaid insurance both had a significantly longer time to transplantation compared with patients with private insurance (P 0.0001). Only 9.3% of patients with VA insurance received transplants compared with 24.5% of patients with private insurance. The cumulative probability of transplantation 3 yr after the initiation of treatment for ESRD was 10, 27, and 11% in VA-, privately, and Medicare/Medicaid-insured patients. Patients with VA insurance received fewer living-donor transplants (31.4% of all transplants in patients with VA insurance were from living donors compared with 40.6% among patients with private insurance; P 0.0001) and fewer multiorgan transplants (1.2% of all transplants in patients with VA insurance were multiorgan compared with 3.0% among patients with private insurance; P 0.008). However, VA-insured patients still had a longer time to kidney transplantation than privately insured patients even when transplants from living donors and multiorgan transplants were excluded (P 0.0001). After adjustment for differences in sociodemographic and clinical factors, the likelihood of transplantation remained lower in patients with VA insurance than in those with private insurance (hazard ratio [HR] 0.66; 95% confidence interval [CI] 0.61 to 0.71; P 0.0001; Table 2), a finding that was consistent within strata defined by diabetes status and age. Specifically, the likelihood of transplantation among patients with VA insurance was lower than for patients with private insurance in patients with (HR for transplantation versus patients with diabetes and private insurance 0.57; 95% CI 0.49 to 0.65) and without diabetes (HR versus patients without diabetes and with private insurance 0.72; 95% CI 0.66 to 0.79), as well as patients who were 65 yr of age (HR versus patients who were 65 yr of age and had private insurance 0.62; 95% CI 0.57 to 0.67) and patients who were 65 yr of age (HR for transplantation versus patients who were 65 yr of age and had private insurance 0.70; 95% CI 0.52 to 0.94). Because there may be geographic differences in access to transplantation, we also determined whether the lower likelihood of transplantation in patients with VA insurance was confounded by state of residence. After additional adjustment, we found that the likelihood of transplantation remained lower in patients with VA insurance, irrespective of the rate of transplantation in their state of residence (Table 2). Racial differences in the time to transplantation were similar in patients with private or VA insurance and most prominent in those who were insured solely by Medicare/Medicaid. Compared with white patients with private insurance, the HR of transplantation for black patients with private insurance was 0.45 (95% CI 0.44 to 0.47) compared with 0.39 (95% CI 0.35 to 0.45) for black patients with VA insurance and 0.27 (95% CI 0.27, 0.28) for black patients with Medicare/Medicaid as the sole insurer (P 0.001 for interaction of black race with Medicare/Medicaid status). The lower likelihood of transplantation in patients with VA insurance compared with private insurance was primarily related to less frequent activation to the waiting list. Patients with VA insurance had a 29% lower likelihood of activation to the waiting list compared with patients with private insurance (HR 0.71; 95% CI 0.67 0.76). Among wait-listed patients, the time to being placed on the waiting list was longer in VA-insured patients (387 d; 95% CI 367 to 413) compared with privately insured patients (275 d; 95% CI 273,279). After being placed on the waiting list, patients with VA insurance had an 11% lower likelihood of transplantation compared with patients with private insurance (HR 0.89; 95% CI 0.82 to 0.96). In additional analyses, we subclassified patients with VA insurance on the basis of the presence or absence of additional private insurance (Figure 2). Patients with VA insurance plus private insurance (n 920) had a significantly higher likelihood of transplantation compared with patients with VA insurance only (n 4328). Patients with VA insurance and additional Medicare/Medicaid insurance (n 2147) did not differ from those with VA insurance only. DISCUSSION We found that patients who had ESRD and were insured by the J Am Soc Nephrol 18: 2592 2599, 2007 Kidney Transplantation among VA Patients 2593

CLINICAL RESEARCH www.jasn.org Table 1. Patient characteristics Characteristic Overall (n 509,391) VA (n 7395) Private (n 144,651) Medicare/Medicaid (n 357,345) Age (yr) 53.7 (12.1) 56.5 (9.3) 52.3 (11.3) 54.3 (12.3) 0.0001 Male gender (%) 54.7 91.0 58.0 52.6 0.0001 Race (%) black 34.8 37.9 30.0 36.7 0.0001 white 57.7 56.6 63.5 55.4 other 7.5 5.5 6.5 7.9 Cause of ESRD (%) GN 13.2 11.6 17.8 11.5 0.0001 diabetes 48.1 50.5 45.2 49.2 other 38.7 37.9 37.0 39.3 Comorbid conditions (%) b IHD 20.7 27.2 18.6 21.3 0.0001 CHF 26.7 25.3 22.1 28.5 0.0001 PVD 12.1 15.7 10.1 12.9 0.0001 stroke 7.5 9.7 5.7 8.2 0.0001 COPD 5.5 8.0 4.1 6.1 0.0001 malignancy 3.9 4.9 4.4 3.6 0.0001 HIV/AIDS c 2.6 3.5 1.9 2.8 0.0001 alcohol/drug 3.2 7.1 1.4 3.8 0.0001 cardiac arrest 0.7 1.1 0.6 0.8 0.0001 Smoker (%) 6.8 12.9 5.6 7.1 0.0001 Inability to ambulate/transfer (%) 3.4 5.1 2.0 4.0 0.0001 Employed (%) d 18.5 10.5 45.5 8.5 0.0001 Median household income (%) $29,000 24.9 27.0 15.6 28.6 0.0001 $29000 to $35,999 24.0 25.3 21.4 25.0 $36,000 to $45,999 25.7 26.8 28.3 24.7 $46,000 25.4 20.9 34.8 21.7 BMI (%) 7.1 8.3 6.7 7.2 0.0001 18.5 to 24.99 31.3 34.9 31.1 31.2 25 to 29.99 24.8 28.5 27.5 23.7 30 to 34.99 14.5 14.4 16.4 13.8 35 to 39.99 7.2 5.7 8.0 6.9 40 4.7 2.9 5.0 2.6 State transplantation rate (per 100 patientyears of dialysis; %) e 7.87 25.4 26.4 23.4 26.3 0.0001 6.15 to 7.86 37.2 33.6 35.0 38.2 4.53 to 6.14 21.7 18.9 24.7 20.6 3.90 to 4.52 8.9 11.1 9.6 8.7 3.09 6.7 10.0 7.5 6.3 a BMI, body mass index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; GN, glomerulonephritis; IHD, ischemic heart disease; PVD, peripheral vascular disease. b Comorbid conditions were determined from the CMS 2728 form. c Information on HIV/AIDS were missing for 36% of all patients and for 39, 35, and 37% of VA-, privately, and Medicare/Medicaid-insured patients, respectively. d Employment status was missing for 5.3% of all patients and for 4.7, 5.0, and 5.5% of VA-, privately, and Medicare/Medicaid-insured patients, respectively. e Based on 2003 rates published by the US Renal Data System. P VA had a substantially lower likelihood of transplantation compared with patients with private insurance and had a similar likelihood of transplantation compared with patients solely with Medicare/Medicaid coverage. This disparity was due in part to a lower use of living-donor transplantation in VA-insured patients. However, when only deceased-donor kidney transplants were considered, VA-insured patients still received transplants less frequently than privately insured patients. In contrast, patients with VA insurance plus private insurance were not disadvantaged. The disparity in access to transplantation was predominantly due to a lower rate of being placed in the waiting list but also due to a lower rate of transplantation among those who were activated to the waiting list. Because transplantation seems to prolong life compared with remaining on dialysis 1,8 and delaying transplantation is associated with poorer patient and transplant survival, 9,10 this appar- 2594 Journal of the American Society of Nephrology J Am Soc Nephrol 18: 2592 2599, 2007

www.jasn.org CLINICAL RESEARCH Figure 1. Time to transplantation from any donor source in patients with various types of insurance (VA, private, Medicare/ Medicaid). ent disparity in access to transplantation may have negative consequences for the health of patients who have ESRD and are insured through the VA. Although we adjusted for multiple potential confounders, it is possible that there are differences between VA-insured and non VA-insured patients not captured in our study that underlie the observed differences in transplantation. Unlike most previous work identifying disparities in kidney transplantation among various patient groups, our study suggests a potentially reversible source of disparity that may be primarily related to the referral and transplantation assessment process provided by the VA. Further studies are needed before any definitive conclusions regarding the VA transplant assessment process or suggestions for change can be made. That access to transplantation among VA-insured patients was no different from that in patients who were insured solely by Medicare/Medicaid may be interpreted as a relative success for the VA system. Once disparaged for providing mediocre care, the VA has made numerous improvements through mandated structural and organizational change, including explicit measurement and accountability for quality and value. Today, the VA is a recognized leader in performance improvement, patient satisfaction, disease prevention, and treatment. 11 However, given that transplantation is both life- and cost-saving compared with continued treatment with dialysis, our findings suggest the need to evaluate merits of a separate VA transplant assessment system. VA-insured patients do not necessarily need to access transplantation through the VA to take advantage of the lifelong insurance for immunosuppressant medications provided by the VA (compared with only 3 yr of coverage provided by Medicare). In addition, patient and allograft survival may be inferior among patients who receive posttransplantation care in VA centers. 12 Our findings bring into question the rationale for maintaining the expense of a separate VA transplant assessment process. There may be more than one reason for why patients who were insured through the VA had a lower likelihood of transplantation. The possibility that the centralized VA system of transplant referral and assessment is inefficient is supported by three of our findings. First, the largest disparity between those with and without VA as the primary insurer was related to the process of being placed on the waiting list rather than transplantation of wait-listed patients. Second, among wait-listed patients, the time to being placed on the waiting list was longer among VA-insured patients. Third, patients with VA insurance plus private insurance (who may be more likely to access transplantation outside the VA system) were not disadvantaged compared with those with private insurance only. Alternatively, the presence of private insurance among veterans may identify a healthier patient population, despite adjustment for the multiple indicators of sociodemographic status and health that were included in our multivariate models. It is important to recognize that with the available data, we are not able to determine definitively which patients accessed transplantation within and outside the VA system; therefore, further studies are needed to determine the reasons for why VA-insured patients had lower access to transplantation. Why VA-insured wait-listed patients were less likely to receive transplants than privately insured wait-listed patients is unclear. Once listed, all patients are placed on the United Network for Organ Sharing deceased-donor waiting list, in which organs are allocated according to prespecified criteria on the basis of waiting time and HLA matching. Possible explanations include a higher rate of temporary suspension as a result of acute illness among VA-insured patients and greater distances between patient residences and the VA transplant centers (a consequence of the fact that four VA transplant centers serve the entire United States), which may render transplantation logistically impossible in certain situations. The process of transplant referral and assessment used by the VA may be suboptimal for a variety of reasons. Any patient with ESRD may be uncertain or ambivalent about transplantation because of fear of the transplant surgery or lack of knowledge about the health benefits of transplantation. 13,14 Because veterans cannot gain access to a VA transplant center until their application is approved by the VA National Transplant Board, opportunities to educate patients about transplantation and the associated health benefits may be missed. Studies to determine whether preferences for transplantation or knowledge of the health benefits of transplantation differ between veterans and nonveterans are needed to determine whether understanding differs between these two groups. In addition, because potential living donors can be formally assessed and educated in only one of the four VA transplants centers and only after a veteran s application has been processed and approved by the National VA transplant board, opportunities for living kidney donation and preemptive transplantation may also be missed among veterans. Consistent with other studies, we found racial disparities to be less marked in the VA. 15 18 However, unlike the majority of previous studies, the VA-insured patients in this study were compared with Medicare/Medicaid patients who also had universal access to health care. Our findings illus- J Am Soc Nephrol 18: 2592 2599, 2007 Kidney Transplantation among VA Patients 2595

CLINICAL RESEARCH www.jasn.org Table 2. Adjusted likelihood of transplantation in patients with various types of medical insurance (Cox multivariate regression model) Parameter HR 95% CI P Medical insurance private 1.0 VA 0.65 0.60 to 0.70 0.0001 Medicare/Medicaid 0.61 0.60 to 0.62 0.0001 Age (per year older) 0.96 0.96 to 0.94 0.0001 Female 0.90 0.88 to 0.91 0.0001 Race white 1.0 black 0.43 0.42 to 0.44 0.0001 other a 0.54 0.53 to 0.56 0.0001 Cause of ESRD glomerular disease 1.0 diabetes 0.90 0.89 to 0.92 0.0001 other 0.80 0.78 to 0.81 0.0001 Unemployed b 0.61 0.60 to 0.62 0.0001 Median household income c $46,000 1.0 $29,000 0.65 0.64 to 0.67 0.0001 $29,000 to $35,999 0.76 0.74 to 0.77 0.0001 $36,000 to $45,999 0.84 0.83 to 0.86 0.0001 State transplantation rate (per 100 patient-years of dialysis) d 7.87 1.0 6.15 to 7.86 0.82 0.79 to 0.85 0.0001 4.53 to 6.14 0.68 0.66 to 0.70 0.0001 3.90 to 4.52 0.54 0.53 to 0.55 0.0001 3.09 0.58 0.56 to 0.60 0.0001 IHD 0.78 0.76 to 0.80 0.0001 CHF 0.65 0.63 to 0.66 0.0001 PVD 0.70 0.68 to 0.73 0.0001 Stroke 0.72 0.69 to 0.75 0.0001 Malignancy 0.49 0.46 to 0.52 0.0001 COPD 0.60 0.56 to 0.63 0.0001 History of cardiac arrest 0.77 0.66 to 0.88 0.0001 HIV/AIDS e 0.72 0.68 to 0.76 0.0001 History of alcohol or drug abuse 0.42 0.39 to 0.45 0.0001 Unable to ambulate 0.31 0.28 to 0.35 0.0001 BMI f 18.5 1.0 18.5 to 24.9 0.99 0.97 to 1.02 0.68 25.0 to 29.9 1.03 1.02 to 1.05 0.0001 30.0 to 34.9 0.92 0.90 to 0.95 0.0001 35.0 to 39.9 0.67 0.65 to 0.70 0.0001 40.0 0.47 0.44 to 0.49 0.0001 Smoker 0.75 0.73 to 0.78 0.0001 a Includes Asian, Native Hawaiian or Pacific Islander, and American Indian/Alaska Native. b Includes unemployed, homemaker, retired due to disability or age, student Employment status could be determined for 95% of patients. c Based on data from the 2002 US Census. d Based on 2003 rates published by the US Renal Data System. e History of HIV/AIDS was available for 63.7% of patients. f As recorded on the CMS 2728 form. trate the complexity of issues that underlie racial disparities in access to health care. Why racial disparities in access to transplantation differed between patients in two publicly funded health care systems is unclear and warrants further study. Our study has limitations that should be considered when interpreting its results. Some of the patients with VA insurance may access transplantation outside the VA. These patients would be expected to access transplantation more rapidly; therefore, their inclusion in the VA-insured group would not negate our findings. Despite the large sample size, completeness of US Renal Data System data, and inclusion of many 2596 Journal of the American Society of Nephrology J Am Soc Nephrol 18: 2592 2599, 2007

www.jasn.org CLINICAL RESEARCH Figure 2. Adjusted time to transplantation in patients with and without additional private insurance (curves for VA only, VA plus Medicare/Medicaid, and Medicare/Medicaid insurance overlap). Cox regression analyses including all variables shown in Table 2. Compared with patients with private insurance, patients with VA as the sole insurer had a lower likelihood of transplantation (HR 0.61; 95% CI 0.56, 0.68; P 0.0001). Patients with VA plus private insurance did not differ from patients with private insurance (HR 0.85; 95% CI 0.71 to 1.00; P 0.06). potential confounders in our analyses, residual confounding by disease severity, potential differences in rate of progression of comorbid conditions among patients with different types of insurance, socioeconomic status, differences in geographic access, or other factors not accounted for in our analysis may have influenced the results. Finally, we cannot conclusively determine the reasons for why veterans had a lower likelihood of transplantation. Although our analysis suggests that this disparity is related to the patient referral and assessment process used by the VA, other possibilities such as patient differences in preference for transplantation might also explain this finding. In summary, we found that patients with VA insurance had decreased access to kidney transplantation compared with patients with private insurance, although VA-insured patients who were also privately insured were not disadvantaged. This disparity in access to transplantation was primarily due to differences in activation to the waiting list. The likelihood of transplantation in VA-insured patients was similar to that among Medicare/Medicaid patients, thus bringing into question the rationale for maintaining two separate governmentfunded systems for accessing transplantation. Further studies are needed before any definitive conclusions regarding the VA transplant assessment process or suggestions for change can be made. CONCISE METHODS All veterans who are enrolled for care in the VA are eligible for transplant services through the VA National Transplant Program. 7 The VA National Transplant Program has four kidney transplant centers, located in Iowa City, IA; Nashville, TN; Pittsburgh, PA; and Portland, OR. To be considered for transplantation, a completed referral from the veteran s primary VA medical center must be sent to the VA National Transplant Office in Washington, DC. The VA National Transplant Office assigns two members of the VA Transplant Review Board to review the application. The VA Transplant Review Board, composed of transplant physicians located throughout the United States, then recommends whether the application should be forwarded to a regional VA transplant center for in-depth review. An approved patient application is assigned to one of the four VA transplant centers. The assigned VA transplant center then contacts the patient for an on-site evaluation and decides whether the patient is a suitable candidate for transplantation. Patients who are found to be suitable are then eligible for living-donor transplantation (if a living donor is available) or placed on the United Network for Organ Sharing deceased-donor waiting list with all other patients who have ESRD and are on the waiting list. Living-donor kidney transplant services are provided at each of the VA transplant centers, but evaluation of potential living donor(s) is not initiated until the veteran is determined to be an eligible candidate for transplantation. The VA National Transplant Office funds the initial transplant evaluation at the VA transplant center; the transplant episode; donor surgery (if applicable); and lodging for the recipient, caregiver, and donor while they are at the VA center for transplant-related care. The referring VA medical center is responsible for follow-up care of the patient and donor (only care related to the loss of the donated kidney), posttransplantation medications, and travel to and from the VA transplant center. In contrast, patients who are insured by Medicare, Medicaid, or private insurers and wish to be considered for living- or deceaseddonor transplantation are referred to the nearest or preferred transplant center by their primary nephrologist. Medicare has developed insurance and reimbursement criteria for medical services that are provided to donors and recipients, including the costs of the donor and recipient pretransplantation evaluation, transplantation, and posttransplantation care. In contrast to VA patients, non-va patients would normally be responsible for travel costs to the transplant center and would receive insurance for immunosuppressant medications only during the first 3 yr after transplantation. Patients who are not insured with the VA cannot receive transplants in VA centers. Data Source and Patient Classification Data from the US Renal Data System were used for this study, which was approved by our hospital ethical review board. Adult patients who were aged 18 to 70 yr and had had their first ESRD treatment (long-term dialysis or transplantation) between April 1, 1995, and December 31, 2004 (n 537,102), were studied. We excluded patients who had missing information regarding their medical insurance (n 27,711). The remaining 509,391 patients were classified according to the type of medical insurance indicated on the Centers for Medicare and Medicaid Services (CMS) 2728 form. The CMS 2728 form is required for all patients with newly diagnosed ESRD regardless of their Medicare status or treatment modality and captures information regarding current medical insurance in the following categories: Medicare, Medicaid, Department of Veterans Affairs (DVA), employer group, other, or none. Because patients may have more than one form of medical insurance, patients were categorized as VA when they had DVA indicated as one of their current forms of medical insurance. Among remaining J Am Soc Nephrol 18: 2592 2599, 2007 Kidney Transplantation among VA Patients 2597

CLINICAL RESEARCH www.jasn.org patients, a second classification of private insurance was created when patients without DVA insurance had employer group or other medical insurance indicated as one of their current forms of medical insurance. The remaining patients all had Medicare, Medicaid, or none indicated as their current form of medical insurance and were classified into a third category of Medicare/Medicaid (all American patients with ESRD and without insurance would be eligible for Medicare/Medicaid). Statistical Analyses The 2 and t tests were used to compare baseline variables between included and excluded patients and patients in the various medical insurance categories. Time to transplantation was determined from the date of first treatment for ESRD using the Kaplan-Meier Method, and group differences were compared with the log-rank test. Patients were followed until death or end of follow-up (December 31, 2004). A Cox multivariate regression analysis was performed to determine the likelihood of transplantation among patients in the various medical insurance categories after adjustment for potentially relevant confounders that were found to be associated with transplantation (P 0.05) in univariate analyses. The following demographic and clinical characteristics were assessed for association with transplantation: Patient age, gender, race (white, black, other), cause of ESRD (diabetes, glomerulonephritis, other causes), current employment status, median withinneighborhood household income (determined by linkage of patient zip codes to data from the 2002 US Census), current smoking status, ambulatory status, comorbid conditions (ischemic heart disease, congestive heart failure, peripheral vascular disease, chronic obstructive pulmonary disease, stroke, malignancy, HIV/ AIDS, alcohol or drug dependence, history of cardiac arrest), and body mass index. To account for geographic differences in access to transplantation, we also adjusted for the 2003 kidney transplantation rate per 100 patient dialysis years in each patient s state of residence. 19 In cases in which data were missing, a category of unknown was created and entered into the model. The proportional hazards assumption was tested using log-negative-log plots of the within-group survivorship probabilities versus log-time as well as time-dependent covariates in the Cox model. Because patients who require multiorgan transplants may be prioritized for transplantation and because patients with living donors may receive transplants more readily, we repeated this analysis while censoring patients at the time of either multiorgan or living-donor kidney transplantation. Two-way interaction terms were used to determine whether access to transplantation between the racial groups differed between veterans and nonveterans. To determine whether observed differences in the likelihood of transplantation among patients in the various medical insurance categories were confounded by the presence of additional medical insurance, we performed a second Cox regression among patients with the following combinations of medical insurance: VA only, VA plus Medicare/Medicaid, VA plus private insurance, and Medicare/ Medicaid only. To determine whether differences in the likelihood of transplantation were due to differences in referral and placement on the waiting list or to differences in transplantation of wait-listed patients, we performed separate models to determine the time from first ESRD treatment to activation on the waiting list (excluding patients who were activated to the waiting list before first ESRD treatment and patients who received transplants without being activated to the waiting list) and the time from activation to the waiting list until deceased-donor transplantation (censoring follow-up at time of living-donor or multiorgan transplantation). All analyses were performed with SAS version 9.1 (SAS Institute, Cary, NC) and S-PLUS version 7.0 (Insightful Software, Seattle, WA). ACKNOWLEDGMENTS J.S.G. is funded by the Michael Smith Foundation for Health Research. M.T. is funded by the Canadian Institutes for Health Research and the Alberta Heritage Foundation. Dr. Gill had full access to the data and takes responsibility for the integrity of the data and the accuracy of the data analysis. Caren Rose performed the statistical analyses. We acknowledge the tremendous support of Allan Collins, Jon Snyder, and Melissa Skeans from the US Renal Data System. The data reported here have been supplied by the United States Renal Data System (USRDS). The interpretation and reporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the US government. DISCLOSURES None. REFERENCES 1. Wolfe R, Ashby V, Milford E, Ojo A, Ettenger R, Agodoa L, Held P, Port F: Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant. N Engl J Med 341: 1725 1730, 1999 2. Laupacis A, Keown P, Pus N, Krueger H, Ferguson B, Wong C, Muirhead N: A study of the quality of life and cost-utility of renal transplantation. 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