Impact of Long-Term Dexamethasone Therapy on the Metabolic Profile of Patients With 21-Hydroxylase Deficiency

CONTEXT: No consensus has been reached regarding the glucocorticoid (GC) to use for congenital adrenal hyperplasia (CAH) during adulthood. Dexamethasone (DEX), because of its longer half-life, could improve compliance; however, no data are available regarding the long-term effects of DEX therapy. OBJECTIVE: To analyze the metabolic effect of DEX therapy for adults with CAH. DESIGN: Retrospective analysis of a CAH cohort receiving DEX therapy. SETTING: Medical School Hospital, São Paulo University, Brazil. PARTICIPANTS: Sixty patients with well-controlled classic CAH (41 women; 30 with salt-wasting) receiving DEX after achievement of final height. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Clinical, laboratory, and metabolic data were compared immediately before DEX and at the last evaluation. RESULTS: The mean age at the last evaluation was 31.9 ± 9.6 years, and the duration of DEX therapy was 11.5 ± 4.9 years. The mean DEX dose was 0.18 ± 0.07 mg/m(2)/d. The body mass index SD score (1.6 ± 1.6 vs 1.5 ± 1.5 mg/m(2); P = 0.65) and obesity prevalence (27% vs 27%) did not differ between evaluations. However, the waist/height ratio (WtHR) had increased from 0.54 ± 0.08 to 0.56 ± 0.1 (P = 0.001). An increase in the homeostatic model assessment for insulin resistance index (2.5 ± 1.3 vs 2.8 ± 1.7; P = 0.03) was observed and positively correlated with the WtHR (r = 0.54). The prevalence of metabolic syndrome (7% vs 10%; P = 0.7) and hypertension (15% vs 13.3%; P = 0.8) did not differ significantly between the two evaluations. CONCLUSIONS: Long-term and low-dose DEX therapy did not lead to increases in obesity or metabolic syndrome, although it was associated with an increased WtHR and greater homeostatic model assessment for insulin resistance observed with chronic use of GCs. DEX appears to be an acceptable option to treat adult CAH.