Context: Several factors can affect adult height (AH) of patients with gonadotropin-dependent precocious puberty (GDPP) treated with depot GnRH analogs.

Objective: To determine factors influencing AH in patients with GDPP treated with depot GnRH analogs.

Patients: Fifty-four patients (45 girls) with GDPP treated with depot GnRH analog who reached AH.

Design: Uni- and multivariate analysis of the factors potentially associated with AH were performed in all girls with GDPP. In addition, clinical features of the girls who attained target height (TH) range were compared with those who did not. Predicted height using both Bayley & Pinneau (BP) tables were compared to attained AH.

Results: In girls, the mean AH was 155.3 ± 6.9 cm (-1.2 ± 1 SD) with TH achieved by 81% of this group. Multiple regression analysis revealed that the interval between chronological age at onset of puberty and at the start of GnRH analog therapy, height SDS at the start and end of therapy and TH explained 74% of AH variance. The predicted height at interruption of GnRH therapy, obtained from BP tables for average bone age was more accurate than for advanced bone age in both sexes. In boys, the mean AH was 170.6 ± 9.2 cm (-1 ± 1.3 SDS) while TH was achieved by 89% of this group.

Conclusions: The major factors determining normal AH in girls with GDPP treated with depot GnRH analogs were shorter interval between the onset of puberty and start of therapy, higher height SDS at the start and end of therapy and TH. Therefore, prompt depot GnRH analog therapy in properly selected patients with GDPP is critical in order to obtain normal AH.