The cost implications of first anniversary renal function after living, standard criteria deceased and expanded criteria deceased donor kidney transplantation

Objectives: To quantify relationships of post-transplant renal function with healthcare costs after kidney transplantation. Methods: Clinical and billing records for Medicare-insured kidney transplant recipients (1995-2003) were drawn from the US Renal Data System. Estimated glomerular filtration rate (eGFR) at 1-year post-transplant was computed with the abbreviated Modification of Diet in Renal Disease equation. Associations of eGFR with total Medicare payments in the second and third post-transplant years were examined by multivariate non-linear regression with spline forms. Adjustment covariates were drawn from the survival prediction model developed by the UNOS Kidney Allocation Review Committee. Results: The sample comprised 7103 living donor (LD), 22,110 standard criteria deceased (SCD), and 2594 expanded criteria deceased (ECD) donor transplant recipients. Regardless of donor type, lower 1-year eGFR was associated with significantly increased expenditures during the second and the third years post-transplant. Marginal costs began to increase as eGFR fell below 45 mL/min/1.73 m² and rose in an accelerating manner. Compared to a reference eGFR of 75 mL/min/1.73 m², 1-year eGFR of 20 ml/min/1.73 m² in SCD recipients was associated with ∼ $17,500 and $18,200 higher adjusted payments in the second and third post-transplant years, respectively. Patterns were similar among recipients of LD and ECD transplants. Limitations: The study sample was limited to Medicare beneficiaries who survived with allograft function to the first transplant anniversary, which may limit generalizability of the findings. eGFR is a surrogate measure of renal function. The design is retrospective and changes in post-transplant management may alter long-term cost implication of renal function. Conclusions: Decreased renal function is significantly associated with higher healthcare expenditures following kidney transplantation. Post-transplant eGFR may be a useful metric for discriminating the economic impact of care strategies that differentially affect renal function.