Total pubertal growth and markers of puberty onset in adolescents with GHD: comparison between mathematical growth analysis and pubertal staging methods

Two methods of determining puberty onset (Preece- Baines model 1 (PB1) and Tanner staging) were used to calculate total pubertal growth (TPG) in adolescents with growth hormone deficiency (GHD). PATIENTS AND METHODS: 34 patients (11 girls) met the following inclusion criteria: isolated GHD, >2 years growth hormone therapy prior to puberty onset, regular weight-adjusted GH dosage, known final height (age >21 years or height velocity <0.5 cm/year), no induction of puberty. PB1 was used to define age and height at onset of the pubertal growth spurt ("take-off"). RESULTS: The results (mean +/- SD) were as follows: in girls, mean age at take-off was 9.8 years; 2.0 +/- 1.1 years before breast stage B2. In boys, mean age at take-off was 11.3 years; 1.4 +/- 0.8 years before testes volume >3 ml. Height at take-off was lower than at Tanner stage 2 by 12.4 +/- 7.6 cm in girls and 7.7 +/- 5.3 cm in boys. TPG was thus markedly greater (p < 0.001) using the PB1 method, as compared with Tanner stage2. Peak height velocity was normal. Final height was -0.5 +/- 0.7 SDS in females and -0.4 +/- 0.9 SDS in males. CONCLUSIONS: The method of measuring TPG from take-off is more objective, and has potentially greater implications for GH therapeutics than the Tanner stage method. In our study, 40% of TPG occurred before "breast stage B2" was attained in GHD girls; whereas 23% of TPG occurred before "testes >3 ml" in GHD boys.