[Incidence and associated factors of anemia within six months after kidney transplantation in pediatric recipients].

Abstract

Objective: Anemia is a common complication following kidney transplantation in children, yet its epidemiological characteristics and associated factors are not fully understood. This study aimed to investigate the incidence and clinical features of anemia within six months after pediatric kidney transplantation and to identify its associated factors, thereby providing evidence for management.

Methods: A single-center retrospective cohort study was conducted on pediatric patients who underwent kidney transplantation at Peking University People' s Hospital from January 2022 to August 2025. Demographic, perioperative, and serial laboratory data up to 6 months post-transplantation were collected. Anemia was diagnosed according to the World Health Organization (WHO) age-specific criteria. Univariate analysis, multivariate binary Logistic regression, and receiver operating characteristic (ROC) curve analysis were performed to identify associated factors and assess their diagnostic value.

Results: The study included 46 pediatric recipients. The incidence of anemia within 6 months post-transplantation was 41.3% (19/46), with normocytic anemia being the most prevalent type (63.1%, 12/19). Multivariate binary Logistic regression analysis showed that age (OR=0.293, P=0.018), postoperative serum urea at 6 months (OR=3.281, P=0.006), and estimated glomerular filtration rate (eGFR) (OR=0.893, P=0.030) were independently associated with anemia. Exploratory stratified analysis suggested that age < 13 years, serum urea >7 mmol/L, and eGFR < 120 mL/(min·1.73 m²) might serve as reference thresholds for clinical screening. ROC curve analysis indicated that postoperative serum urea had the best diagnostic value for anemia (area under the curve=0.890, P < 0.001). Hemoglobin levels began to differ significantly between the anemic and non-anemic groups from the third month postoperative onward, with the gap widening over time.

Conclusion: This study demonstrates a high incidence of early-onset anemia after pediatric kidney transplantation, primarily mild to moderate normocytic anemia. It is associated with younger age and suboptimal allograft function, with the divergence in hemoglobin levels becoming apparent from the third month postoperative. Close monitoring of high-risk children, particularly those aged < 13 years or with serum urea >7 mmol/L and eGFR < 120 mL/(min·1.73 m²), and early intervention may help reduce the occurrence or severity of post-transplant anemia.