BMI-SDS Changes During GnRHa Therapy in 150 Girls with Idiopathic Central Precocious Puberty: Follow-up Through Final Height

Objective: To evaluate longitudinal changes in body mass index-standard deviation score (BMI-SDS) in girls with central precocious puberty (CPP) treated with gonadotropin-releasing hormone analogues from treatment initiation to final adult height. Methods: This retrospective study included 150 girls with idiopathic CPP treated with leuprolide acetate and followed to final adult height. BMI-SDS was assessed at treatment initiation, at 1 year of therapy, at treatment completion, and at final adult height. Patients were categorized according to BMI-SDS at the time of diagnosis as underweight, normal weight, overweight (OW), or obese (OB). BMI-SDS was evaluated at predefined time points and examined within baseline weight groups, and transitions between BMI-SDS categories were analyzed across the follow-up period. In addition to baseline weight status, participants were categorized as small for gestational age (SGA) or appropriate for GA (AGA) based on birth weight for gestational age. Results: In normal-weight girls, BMI-SDS increased significantly during the first treatment year and then declined toward final height, with no difference between baseline and final height. BMI-SDS remained stable in those OW or OB at treatment initiation. BMI-category distribution changed over follow-up (overall p=0.014), OW+OB prevalence increased during treatment (48.6%→56.6%) and decreased by final height (45.3%) (baseline vs final p=0.533). By final height, OB increased (p=0.0076) and OW decreased (p=0.006), while normal-weight prevalence did not differ from baseline (p=0.098). BMI-SDS was lower in SGA than AGA at baseline, year 1, and treatment completion (p=0.04, p=0.04, and p=0.01, respectively), but not at final adult height (p=0.6). In multivariable analysis, baseline BMI-SDS was inversely related to ΔBMI-SDS (treatment end-baseline) (β=-0.174, 95% confidence interval -0.291 to -0.057; p=0.004). Conclusion: In this large cohort of girls with idiopathic CPP followed through final adult height, BMI-SDS showed no sustained increase at final height across baseline weight groups, and the SGA-AGA differences observed earlier were not maintained. Baseline BMI-SDS was the key independent determinant of ΔBMI-SDS (treatment end-baseline), with lower baseline values predicting greater increases.