Comparing adult height gain and menarcheal age between girls with central precocious puberty treated with gonadotropin-releasing hormone agonist alone and those treated with combined growth hormone therapy

PURPOSE: This study aimed to investigate the outcomes of gonadotropin-releasing hormone agonist (GnRHa) therapy with or without growth hormone (GH) therapy for girls with idiopathic central precocious puberty (CPP). METHODS: The medical records of 166 girls diagnosed with CPP from 2002 to 2017 were retrospectively reviewed. All included patients were treated with GnRHa for ≥36 months. Changes in height standard deviation score (SDS) for bone age, chronological age (CA), and predicted adult height (PAH) were assessed for the first three years of treatment. The final height gain SDS was calculated as the difference between the initial PAH SDS and adult height (AH) SDS; these were then compared between the GnRHa group (group A, n=135) and the combined GnRHa/GH group (group B, n=31). RESULTS: The initial mean CA was 7.89 years. The mean menarcheal age was 13.12 years (group A, 13.1±0.99; group B, 13.18±0.58 years; P=0.755). PAH SDS at the start of GnRHa treatment and AH SDS were significantly lower in group B than in group A (PAH SDS: -2.20±0.83 vs. -3.19±0.84, P<0.001; AH SDS: 0.18±084 vs. -0.30±0.66, P=0.021). The increase in PAH SDS was higher in group B than in group A for the first three years of GnRHa treatment (1.66±0.66 vs. 2.35±0.93, P<0.001). The height gain SDS was significantly higher in group B than in group A (2.5±0.75 vs. 2.93±1.02, P=0.048). Younger age, higher PAH at the start of treatment, and a greater increase in PAH SDS during the first year of GnRHa treatment positively affected AH. CONCLUSIONS: The combined GH group had more additional height gain than the GnRHa-alone group.