Saritha Ranabothu, Jodi M. Smith, James D. Perkins, Lyndsay A. Harshman, Sharon Bartosh, Rachel M. Engen
BACKGROUND: Pediatric kidney transplant recipients typically receive low-KDPI deceased donor kidneys but often experience higher HLA mismatches. The relationship between KDPI and HLA mismatch and their combined effect on graft and patient outcomes in children has not been well studied. METHODS: We conducted a retrospective review of SRTR data in evaluating the association between KDPI and HLA mismatch. We included all pediatric kidney transplant recipients under 21 years of age who received a transplant between December 4, 2014, to December 31, 2023. RESULTS: There was no significant difference in death-censored graft survival between KDPI < 30% and ≥ 30% (HR 0.74; 95% CI: 0.51-1.08; p = 0.11). However, recipients with HLA MM of 3-6 had significantly worse graft survival than those with 0-2 mismatches (HR 0.62; 95% CI: 0.42-0.92; p = 0.02). In combined models, any group with HLA MM 3-6 had worse graft survival regardless of KDPI. No significant differences were found in patient survival across groups. CONCLUSION: HLA mismatch is a stronger predictor of graft outcomes than KDPI in pediatric kidney transplantation. The limited number of high-KDPI donors in pediatric recipients may explain the lack of significant association with KDPI. These findings support efforts to minimize HLA mismatches in pediatric allocation strategies.