Aims/Purpose: Pediatric kidney transplant (KTx) recipients are at increased risk for hospitalization due to infections compared to healthy peers. This study aims to analyze risk factors influencing infections in transplanted children and adolescents and to assess factors affecting renal function decline (ΔeGFR). Infection rates in the KTx group were further compared to a large insurance-based cohort of non-transplanted children.
Methods: We conducted a retrospective, monocentric analysis of pediatric kidney transplant recipients, assessing infection incidence, type, and frequency. Two age subgroups were compared: preschool children (<6 years) and school-aged children/adolescents (≥6 years). Only infections leading to hospitalization were considered. A hurdle regression model was applied to assess infection risk and frequency, considering key factors such as age, cold ischemia time (CIT), and HLA mismatches. Additionally, a linear regression model was used to evaluate the impact of these factors on ΔeGFR at 3-12 and 3-24 months post-transplant. The infection rates of the transplant cohort were compared to a large non-transplanted pediatric insurance cohort, where hospitalizations due to infection incidence and type were recorded.
Results: Infections in the transplant cohort: Age was a significant predictor of both infection occurrence and frequency (p<0.05). CIT showed a minor effect on infection risk, while HLA mismatches at 24 months were associated with a higher probability of acquiring any infection.
Renal function (eGFR decline): At 12 and 24 months post-transplant, ΔeGFR was significantly influenced by HLA mismatches and CIT at 24 months (p<0.05).
Comparison with the healthy cohort: As expected, infection rates were markedly higher in the transplant group. Preschool children had an 88-fold higher infection rate than their healthy counterparts, while school-aged children and adolescents exhibited an even greater relative risk (127-fold increase).
Conclusion: Pediatric kidney transplant recipients exhibit significantly increased infection-related hospitalization rates, particularly in older children and adolescents. Age, HLA mismatches, and CIT impact both infection risk and long-term renal function. The comparison with a healthy cohort underscores the substantial burden of severe infections in this vulnerable population, and emphasizes the need for age-specific infection prevention strategies and optimized immunosuppressive management in pediatric transplant recipients.