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