Near-final adult height after GnRHa plus growth hormone in central precocious puberty: a single-center cohort study and predicted adult height validation audit.

BACKGROUND

Whether adjunctive recombinant human growth hormone (rhGH) improves near-final adult height (NFAH) during gonadotropin-releasing hormone analog (GnRHa) therapy for central precocious puberty (CPP) remains uncertain, and predicted adult height (PAH) may reflect treatment selection and prognosis.

METHODS

We analyzed a single-center retrospective cohort of 235 children with CPP who initiated GnRHa between January 2018 and December 2020. The primary endpoint was chart-recorded NFAH in the female-only maturity-ascertained cohort (n = 91); the criterion-confirmed all-sex set included 94 patients. The primary adjusted model (M2) included treatment, baseline age, body mass index (BMI), IGF-1, BA-CA, and baseline height; baseline bone age was not entered separately because bone age = chronological age + BA-CA. Missing baseline covariates were handled using 20 imputations by chained equations. Height gain and change in height standard deviation score (SDS) from baseline to 24 months were secondary outcomes.

Results

Mean NFAH was 160.17 cm with GnRHa alone and 161.87 cm with GnRHa + rhGH. The adjusted M2 association was +2.26 cm (95% CI 0.12 to 4.40); the chart-PAH-conditioned M3 estimate was +0.58 cm (-1.60 to 2.75) and was treated as diagnostic. At 24 months, M2 estimates were +3.23 cm (2.00 to 4.46) for height gain, +3.24 cm (2.03 to 4.46) in analysis of covariance (ANCOVA) of attained height, and +0.46 SDS (0.27 to 0.66). In the criterion-confirmed female bone-age cohort, M2 estimates were +0.00 years (-0.27 to 0.27) for bone age at 24 months and -0.14 years (-0.30 to 0.03) for bone-age progression.

CONCLUSIONS

Adjunctive rhGH was associated with greater growth over 24 months and a positive, imprecisely estimated NFAH difference. Because this was an observational study, ascertainment criteria were heterogeneous, and the NFAH estimate was sensitive to PAH adjustment and criterion restriction, the adult-height finding should be interpreted cautiously.