Abstract
BACKGROUND: Growth hormone (GH) therapy affects linear growth and may influence hematopoiesis, but dynamic hemoglobin (Hb) changes in children remain unclear. OBJECTIVE: To characterize longitudinal Hb trajectories during weekly GH treatment in short stature, including idiopathic short stature (ISS) and growth hormone deficiency (GHD), and to assess their associations with growth response. METHODS: This retrospective cohort study included 165 children with short stature who received once-weekly PEGylated GH therapy for at least 12 months. Hematologic/growth-related parameters were collected at baseline, 6 and 12 months. Group-based trajectory modeling (GBTM) identified Hb trajectory groups. Spearman correlation analysis was performed to evaluate the association between Hb, red blood cell (RBC) count, and insulin-like growth factor 1 (IGF-1). Multivariate logistic regression was used to identify predictors of Hb improvement (≥5 g/L). RESULTS: Three distinct Hb trajectory groups were identified: ascending (n = 82), ascending-then-descending (n = 51), and stable (n = 32). The ascending group demonstrated the most favorable height SDS improvement at 12 months (mean ΔHtSDS = 1.01), while the ascending-then-descending and stable groups showed more modest gains. IGF-1 levels were moderately correlated with Hb at 12 months (ρ = 0.308, p = 0.001) and RBC counts (ρ = 0.236, p = 0.014). Logistic regression revealed no independent baseline predictor of Hb improvement; however, the inclusion of Hb trajectory group significantly enhanced the predictive model for growth response (adjusted R² increased from 0.129 to 0.240; p = 0.018). CONCLUSION: Hb trajectories vary significantly among children receiving GH therapy and are moderately associated with height outcomes. Longitudinal monitoring of Hb may serve as a cost-effective dynamic biomarker to guide personalized GH dose titration in pediatric growth disorders. If validated, Hb monitoring may serve as a practical biomarker for personalized GH dosing in pediatric growth disorders.