Economic Evaluation of Extending Medicare Immunosuppressive Drug Coverage for Kidney Transplant Recipients in the Current Era
Authors: Kadatz Matthew , Gill John S. , Gill Jagbir , Formica Richard N. , Klarenbach Scott 
Published: November 2019

Significance Statement
Kidney transplant recipients must take immunosuppressive medications to prevent rejection of their transplant kidney. Coverage of immunosuppressive drugs under Medicare’s ESKD program ends 36 months after transplantation, putting patients at risk for premature transplant failure. The authors analyzed the cost and benefits of extending Medicare immunosuppressive drug coverage for the entire duration of survival after transplantation using current generic immunosuppressive drug costs and estimates of increased transplant survival. From the Medicare payer perspective, extending immunosuppression drug coverage was cost-saving and led to better patient outcomes compared with the current policy. The findings may be useful in advancing legislative efforts to ensure kidney transplant recipients have access to essential life-saving immunosuppressive medications.

Background
Kidney transplant recipients must take immunosuppressant drugs to prevent rejection and maintain transplant function. Medicare coverage of immunosuppressant drugs for kidney transplant recipients ceases 36 months after transplantation, potentially increasing the risk of transplant failure. A contemporary economic analysis of extending Medicare coverage for the duration of transplant survival using current costs of immunosuppressant medications in the era of generic equivalents may inform immunosuppressant drug policy.

Methods
A Markov model was used to determine the incremental cost and effectiveness of extending Medicare coverage for immunosuppressive drugs over the duration of transplant survival, compared with the current policy of 36-month coverage, from the perspective of the Medicare payer. The expected improvement in transplant survival by extending immunosuppressive drug coverage was estimated from a cohort of privately insured transplant recipients who receive lifelong immunosuppressant drug coverage compared with a cohort of Medicare-insured transplant recipients, using multivariable survival analysis.

Results
Extension of immunosuppression Medicare coverage for kidney transplant recipients led to lower costs of −$3077 and 0.37 additional quality-adjusted life years (QALYs) per patient. When the improvement in transplant survival associated with extending immunosuppressant coverage was reduced to 50% of that observed in privately insured patients, the strategy of extending drug coverage had an incremental cost–utility ratio of $51,694 per QALY gained. In a threshold analysis, the extension of immunosuppression coverage was cost-effective at a willingness-to-pay threshold of $100,000, $50,000, and $0 per QALY if it results in a decrease in risk of transplant failure of 5.5%, 7.8%, and 13.3%, respectively.

Conclusions
Extending immunosuppressive drug coverage under Medicare from the current 36 months to the duration of transplant survival will result in better patient outcomes and cost-savings, and remains cost-effective if only a fraction of anticipated benefit is realized.