Risk-Stratified 2 mg/kg ATG Induction in Kidney Transplantation: Comparing Two- and Three-Dose Regimens at a Single Center.

BACKGROUND: Antithymocyte globulin (ATG), an effective induction agent in kidney transplantation; especially for high-risk recipients is associated with infection risks, hematologic toxicity, and high costs. This study assessed clinical and economic outcomes of a risk-based ATG protocol comparing 4 vs 6 mg/kg regimens. METHODS: We conducted a single-center retrospective study of 260 kidney transplant recipients stratified by immunologic risk to receive 2 (4 mg/kg total) or 3 (6 mg/kg total) 2 mg/kg ATG doses. Outcomes included acute rejection, tacrolimus levels, and readmissions. Multivariate analysis adjusted for PRA and donor factors. Costs were estimated using standardized ATG pricing. RESULTS: ATG dosing (2 doses for 63% of patients; 3 doses for 37%) resulted in similar biopsy-proven acute rejection rates (17.1% vs 10.6%, p = .224). However, borderline rejection was significantly higher in the 2-dose group. Time to rejection after transplant was not significantly different between the 2 groups, and tacrolimus levels were also similar. ATG dose was not an independent predictor of rejection; PRA was significant in the model adjusted for KDPI. A cost effectiveness analysis showed that the 2-dose regimen would have saved approximately $684,000 in this patient population. CONCLUSIONS: A 2-dose ATG regimen demonstrated comparable clinical efficacy with respect to biopsy-proven rejection and short-term post-transplant outcomes, while offering substantial cost savings. Although the 2-dose group experienced significantly higher rates of borderline rejection, this did not translate into inferior clinical outcomes, suggesting these episodes may be manageable within a steroid-free program utilizing protocol biopsies. These findings support risk-adapted induction strategies but highlight the role of clinician judgment in real-world applications.