The validity of the Bayley-Pinneau method in predicting final adult height at the onset of puberty in patients with classic congenital adrenal hyperplasia.

Introduction: The final adult height (FAH) of patients with congenital adrenal hyperplasia (CAH) is often lower than the predicted adult height (PAH) using the Bayley-Pinneau (B&P) method. The aim of the current work was to test the validity of B&P in predicting FAH from a bone age (BA) measurement performed at onset of puberty.

Material And Ethods: This was a retrospective longitudinal observational convenience single-centre study. The study included 54 patients (male and female) with classic CAH, whether salt-wasting (SW) or simple virilising (SV), who had reached FAH. The results of auxological measurements and hormonal data around the time of puberty were retrieved from files. Predicted adult height (PAH) was calculated from a BA taken at onset of puberty and compared with FAH.

Results: The median PAH SDS at the onset of puberty (-1.5) was significantly greater than the median FAH SDS (-2.2) (p < 0.001). The median target height SDS (-0.8) was significantly higher than the median FAH SDS (-2.2) (p < 0.001). FAH and FAH SDS were significantly worse in females (150.36 ± 7.23; -2.05 ± 1.13) than in their male counterparts (162.86 ± 3.30; -1.53 ± 0.51) (p value < 0.001; 0.048). In patients with good control, there was no difference between PAH SDS (-1.7) and FAH SDS (-1.5) (p value = 0.37). In patients with poor control (over- or under-treated) FAH SDS (-2.1) was significantly lower than PAH SDS (-1.4) (p value < 0.001).

Conclusion: The B&P method was able to accurately predict FAH in children with classic CAH, who were medically well controlled (based on 17-hydroxyprogesterone levels), but overestimated it by a significant 0.7 SD in poorly-controlled patients.