Objective: Adrenal insufficiency (AI) is characterized by increased mortality compared to general population, mainly due to cardiovascular disease. Conventional glucocorticoid (GC) replacement therapy has a role in determining the increased mortality risk. Primary outcome of the current study was to evaluate the impact of 10 years of conventional GCs and DR-HC on body weight changes in treatment-naive patients with AI. Secondary outcomes were changes from baseline to 5 and 10 years in anthropometric and metabolic profile, insulin sensitivity, cardiovascular, and bone parameters. Design and methods: We prospectively randomized 42 patients to conventional GCs (cortisone acetate or hydrocortisone) and 44 to DR-HC (1:1). Anthropometric, metabolic, cardiovascular, and bone parameters were evaluated at baseline and after 5 and 10 years of follow-up. This trial is registered at ClinicalTrials.gov NCT06260462. Results: At 10 years of follow-up, patients with conventional GCs had significantly higher values of BMI (P = .031), waist circumference (P = .047), systolic blood pressure (P = .039), total and LDL cholesterol (P = .041 and P = .042), HbA1c (P = .040), HOMA-IR (P = .006), AUC(2h) of glucose (P < .001), thickness of the interventricular septum in diastole and of the posterior wall (both P < .001) and significantly lower values of oral disposition index (P = .001) and ISI-Matsuda (P < .001), lumbar spine T score (P = .036), and femoral neck Z score (P = .026), compared to patients treated with DR-HC. Conclusions: In patients with treatment-naive AI, 10 years of conventional GC treatment is associated with a worsening of metabolic, insulin-sensitivity, cardiac, and bone outcomes, while DR-HC had no impact on them achieving a lower risk of developing comorbidities.