Clinical outcomes and treatment adequacy assessment in congenital adrenal hyperplasia: A Single-Center experience with Long-Term Follow-Up.

PURPOSE: Congenital adrenal hyperplasia (CAH), caused by defects in adrenal steroidogenesis, presents with variable clinical severity. This study aimed to compare clinical outcomes between classical (C-CAH) and nonclassical CAH (NCCAH), and to assess treatment adequacy in classical 21-hydroxylase deficiency using 17-hydroxyprogesterone (17-OHP) levels. METHODS: This retrospective cohort study included 91 CAH patients confirmed by cosyntropin stimulation or genetic analysis, and classified as C-CAH (n = 63) and NCCAH (n = 28). Treatment adequacy assessment focused on classical 21-hydroxylase deficiency patients (n = 59). Demographic characteristics, clinical findings, biochemical parameters, and treatments were evaluated. Treatment status was classified as adequate, under-, or overtreatment based on the average of the last three 17-OHP levels obtained within the past year. RESULTS: 21-hydroxylase deficiency was the predominant subtype. C-CAH patients were younger at diagnosis (p < 0.001) and more often presented with atypical genitalia (41.3%) or adrenal crisis (23.8%), whereas hirsutism (50%) and menstrual irregularities (32.1%) were common in NCCAH. All C-CAH patients and 21.4% of NCCAH patients received glucocorticoid therapy. The median hydrocortisone-equivalent glucocorticoid dose was significantly higher in C-CAH (20 mg/day) compared with NCCAH (11.65 mg/day, p < 0.001). In classical 21-hydroxylase deficiency, longer follow-up duration independently predicted adequate treatment (OR = 1.031; 95% CI: 1.006–1.056; p = 0.013). Glucose metabolism disorders were more prevalent in the overtreatment group (47.1% vs. 33.3% vs. 13.3%, p = 0.038), while other metabolic complications did not significantly differ between groups (p > 0.05). CONCLUSION: Our findings highlight distinct clinical and treatment patterns in CAH. Longer follow-up duration independently predicts treatment adequacy in classical CAH, emphasizing the importance of long-term specialized care. Our 17-OHP-based treatment adequacy assessment provides a practical monitoring framework with clear implications for preventing overtreatment associated metabolic complications.