Low Impact of Urinary Cortisol in the Assessment of Hydrocortisone Replacement Therapy replacement therapy (HRT) lead to a higher prevalence of cardiovascular disease and diabetes mellitus and affect quality of life [6, 7]. Therefore, surveillance of cortisol replacement therapy is essential to avoid serious side effects. Due to the pharmacokinetic structure of oral hydrocortisone, biochemical analyses of serum cortisol are of no use and surveillance should be achieved through clinical monitoring [8]. Recently, several studies used urinary corticosteroid profiles to monitor replacement doses in patients with adrenal hypofunction [9, 10]. However, a possible difference in the metabolism of cortisol between healthy subjects and patients with primary or secondary AI may confound interpretation. In fact, little information is available whether urinary excretion of cortisol is a useful alternative to assess the quality of HRT. Aim of the present study was to perform a quantitative analysis of urinary cortisol excretion of affected AI patients compared to healthy subjects.