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-naïve 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. We prospectively randomised 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. At 10 years of follow-up, patients with conventional GCs had significantly higher values of BMI (p=0.031), waist circumference (p=0.047), systolic blood pressure (p=0.039), total and LDL cholesterol (p=0.041 and p=0.042), HbA1c (p=0.040), HOMA-IR (p=0.006), AUC2h of glucose (p<0.001), thickness of the interventricular septum in diastole and of the posterior wall (both p<0.001) and significantly lower values of oral disposition index (p=0.001) and ISI-Matsuda (p<0.001), lumbar spine T score (p=0.036) and femoral neck Z score (p=0.026), compared to patients treated with DR-HC. In patients with treatment-naïve 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.