Acute Kidney Injury After Pediatric Hematopoietic Stem Cell Transplantation: Incidence, Risk Factors, and Outcomes

Acute kidney injury (AKI) commonly occurs after pediatric hematopoietic stem cell transplantation (HSCT) and may lead to increased mortality and long-term kidney complications. However, observational data on the clinical determinants of HSCT-associated AKI remain heterogeneous.

This retrospective cohort study included pediatric patients who received HSCT between March 2019 and March 2023 with a minimum follow-up of 6 months. AKI was defined according to KDIGO criteria using serum creatinine. Results were analyzed at both the patient level (incidence, risk factors, and chronic kidney disease outcomes) and the episode level (timing, triggers, KDIGO severity). Multivariable analysis was performed using Firth penalized logistic regression to identify independent predictors of AKI.

Of 88 patients screened, 68 were included in the study, with a median follow-up of 23.7 months. AKI developed in 18 patients (26%). Older age (median 151.5 vs. 50 months, p = 0.001), having a malignant indication (OR = 8.00, 95% CI 2.41-26.57, p = 0.001), and using peripheral blood stem cells (OR = 3.56, p = 0.027) were significant predictors in univariate analysis. In Firth penalized logistic regression, only older age remained an independent predictor (adjusted OR = 1.40 per year, 95% CI 1.15-1.69, p = 0.001; C-statistic = 0.912). There were 36 AKI episodes among the 18 patients, with 66.7% of these occurring within the first 100 days. Two episodes occurred on the day of transplantation in patients who received cryopreserved products. Infection/antibiotic exposure was the most common trigger (44%). Most episodes (91.7%) were KDIGO stage 1, while all stage 2-3 episodes happened in patients with GVHD and were always fatal. Four patients developed new CKD, all of whom had previous AKI. No CKD was found in patients without AKI. Hypertension was seen early after transplant in 31% of patients and continued in 9%.

In this group, AKI after pediatric HSCT showed a bimodal risk pattern: frequent mild cases triggered by infection within the first 100 days, and rare but always fatal severe cases linked to GVHD. Older age was the only independent predictor in multivariable analysis. All patients who developed CKD had a history of AKI, supporting the link between AKI and CKD in this population. These results suggest that high-risk HSCT patients should have risk-based monitoring, early involvement of nephrology, and use of biomarkers for better surveillance.