Clinical Variability in Congenital Adrenal Hyperplasia: A Distinct Subgroup with a Low Glucocorticoid Dose Requirement.

INTRODUCTION

Some children with classic congenital adrenal hyperplasia (CAH) achieve excellent control on very low glucocorticoid doses. We aimed to characterize these patients and assess the timing of their low-dose requirements.

METHODS

We reviewed charts of patients with salt-wasting CAH due to 21-hydroxylase deficiency, defining low-dose glucocorticoid as <10 mg/m2/day. Demographic and growth data were compared with a matched group on standard doses.

RESULTS

Among 154 patients with CAH, 14 (9%) required low-dose glucocorticoid therapy (<10 mg/m2/day), including 8 boys (57%) and 6 girls (43%). The average age at treatment initiation was 2.1 years, comparable to a matched group of 23 patients (48% boys). The low-dose group received 8.8 ± 1.2 mg/m2/day versus 14.9 ± 3.9 mg/m2/day in the matched group (p < 0.001), with similar fludrocortisone doses (0.1 ± 0.05 mg). No differences were observed in weight, height, or height velocity. Of the 14 patients on low-dose treatment, 3 experienced an increase in their glucocorticoid dose requirement above 10 mg/m2/day at ages 10.3, 10.8, and 8.5 years after being on 6.3-9.8 mg/m2/day for 6.4-8.5 years. The remaining 11 patients are currently on 5.89-10 mg/m2/day with a duration on low-dose therapy ranging from 0.48 to 8.65 years.

CONCLUSION

Our findings highlight a subgroup of patients with 21-hydroxylase deficiency who achieve good control on low glucocorticoid doses from early childhood. The factors underlying this and the transient need for low doses in some remain unclear.