Glucocorticoid treatment regimen and health outcomes in adults with congenital adrenal hyperplasia

Background Adults with congenital adrenal hyperplasia (CAH) are treated with a wide variety of glucocorticoid treatment regimens. Objective, design and methods To test whether drug dose and timing of glucocorticoid treatment regimen impacts on health outcomes. This was a cross-sectional study of 196 adult CAH patients in whom treatment and health outcomes were measured. Glucocorticoid dose was converted to prednisolone dose equivalent (PreDEq) using three published formulae. Associations between the type of glucocorticoid regimen and PreDEq with specific health outcome variables were tested using partial correlation and principal components analysis (PCA). Results Patients on dexamethasone had lower androgens and ACTH but greater insulin resistance compared with those receiving hydrocortisone or prednisolone. Dexamethasone dose and once daily administration were associated with insulin resistance. Partial correlation analysis adjusted for age and sex showed PreDEq weakly correlated (r < 0.2) with blood pressure and androstenedione. Mutation severity was associated with increased PreDEq (F3,141 = 4.4, P < 0.01). In PCA, 3 PCs were identified that explained 62% of the total variance (r2) in observed variables. Regression analysis (age and sex adjusted) confirmed that PC2, reflecting disease control (androstenedione, 17-hydroxypregesterone and testosterone), and PC3, reflecting blood pressure and mutations (systolic and diastolic blood pressure and mutation severity), related directly to PreDEq (r2 = 23%, P < 0.001). Conclusions In adults with congenital adrenal hyperplasia, dexamethasone use was associated with lower androgens but greater insulin resistance, and increasing glucocorticoid dose associated with increased blood pressure, poor disease control and mutation severity.