| 2007 JASN IMPACT FACTOR 7.111 | HOME AUTHOR INFO EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP | |||
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Clinical Research |




* 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
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{at}providencehealth.bc.ca
Received for publication January 14, 2007. Accepted for publication May 29, 2007.
| Abstract |
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| Introduction |
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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 |
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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).
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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).
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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.
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| DISCUSSION |
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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 illustrate 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 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 government-funded 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 |
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In contrast, patients who are insured by Medicare, Medicaid, or private insurers and wish to be considered for living- or deceased-donor 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 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 within-neighborhood 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).
| DISCLOSURES |
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| Acknowledgments |
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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.
| Footnotes |
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| REFERENCES |
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