Endocrine Abstracts

Introduction: Addison disease (AD) is associated with high risk of decreased bone mineral density (BMD) and osteoporosis. Causes are complex, including lifelong glucocorticoid replacement therapy. Several studies have pointed a significant relationship between glucocorticoid dose and low BMD in patients with AD. The aim of our study is to assess the impact of glucocorticoid replacement dose on BMD among Tunisian patients with AD.

Patients and Methods: We conducted a descriptive and analytical cross- sectional study that included 50 patients with AD taking glucocorticoid replacement therapy for at least 5 years and followed at the Endocrinology department of Hedi Chaker University hospital, Sfax, Tunisia, from March 2020 to July 2021. BMD was evaluated using dual-energy X-ray absorptiometry (DEXA), at the lumbar spine (L1-L4) and femoral neck sites. The relationship between glucocorticoid dose and BMD was assessed.

Results: Patients had a mean age of 49.5±13.9 years (18-78 years) and a disease duration with a mean of 13.9 ±8.7 years (5-35 years) and 80% were women. None of the participants reported having spontaneous or traumatic fracture. All patients were treated from diagnosis with hydrocortisone (HC), distributed in two daily doses in 67% of patients. Twelve percent of patients received fludrocortisone as mineralocorticoid replacement. Average daily HC dose at the time of AD diagnosis was 25.7±9.1 mg (15-50 mg) corresponding to 0.47±0.21 mg/kg (0.18-1.08 mg/kg) and an average daily dose adjusted for body surface area of 16.29±7.54 mg/m^² (15.6-37.94 mg/m^²). During follow-up, the average daily HC dose was 27.4±6.7 mg (15-42.1 mg) corresponding to 0.388±0.128 mg/kg (range, 0.175-0.711 mg/kg) and a mean dose per body surface area of 14.836±4.658 mg/m^² (7.486-31.460 mg/m^²). Mean cumulative hydrocortisone dose was 374.636±283.821 mg (60–1184, 94 mg). Low BMD (less than 2 standard deviations [SD] of the mean value of an age-matched reference population) was depicted in almost half of patients (48%). Twelve (24%) patients had osteoporosis. As well, osteopenia was recorded in 24% of patients. Patients with osteoporosis were older (P=0.018) receiving higher mean daily dose than normal BMD ((26.5±8.3 mg/day vs 25.6 ±6.3 mg/day,P=0.9). Mean cumulative HC dose was higher in patients with osteopenia/osteoporosis than those with normal osteodensitometry but without significant correlation (462.2±373.2 mg vs 344.6±245.5 mg, P=0.48).

Discussion: Glucocorticoid replacement therapy during AD is associated with low BMD requiring better therapeutic adjustment of HC doses.