Income-Related Disparities in Kidney Transplant Graft Failures Are Eliminated by

Income-Related Disparities in Kidney Transplant Graft Failures Are Eliminated by Medicare's Immunosuppression Coverage

R. S. Woodward a,*, T. F. Page b , R. Soares b , M. A. Schnitzler c , K. L. Lentine c and D. C. Brennan d
a Departments of Health Management and Policy and Economics, University of New, Hampshire, Durham, NH b Department of Health Policy and Management, Florida International University, Miami, FL c Department of Economics, Federal University of Ceara, Fortaleza-CE, Brazil d Center for Outcomes Research, Saint Louis University School of Medicine, St. Louis, MO e Division of Nephrology, Washington University School of Medicine, St. Louis, MO
* Corresponding author: Robert S. Woodward, rsw@unh.edu
Copyright © 2008 American Society of Transplantation and the American Society of Transplant Surgeons
KEYWORDS
Immunosuppression • insurance • kidney graft survival • Medicare • outcomes
ABSTRACT

Beginning January 1, 2000, Medicare extended coverage of immunosuppression medications from 3 years to lifetime based on age >65 years or disability. Using United States Renal Data System (USRDS) data for Medicare-insured recipients of kidney transplants between July 1995 and December 2000, we identified four cohorts of Medicare-insured kidney transplant recipients. Patients in cohort 1 were individuals who were both eligible and received lifetime coverage. Patients in cohort 2 would have been eligible, but their 3-year coverage expired before lifetime coverage was available. Patients in cohort 3 were ineligible for lifetime coverage because of youth or lack of disability. Patients in cohort 4 were transplanted between 1995 and 1996 and were ineligible for lifetime coverage. Incomes were categorized by ZIP code median household income from census data. Lifetime extension of Medicare immunosuppression was associated with improved allograft survival among low-income transplant recipients in the sense that the previously existing income-related disparities in graft survival in cohort 2 were not apparent in cohort 1. Ineligible individuals served as a control group; the income-related disparities in graft survival observed in the early cohort 4 persisted in more recent cohort 3. Multivariate proportional hazards models confirmed these findings. Future work should evaluate the cost effectiveness of these coverage increases, as well as that of benefits extensions to broader patient groups.

Received 02 April 2008, revised 30 July 2008 and accepted for publication 18 August 2008
http://www3.interscience.wiley.com/journal/121511587/abstract?CRETRY=1&SRETRY=0