Endocrine Abstracts

Forty seven patients suffering from Addison’s disease (AD: 12 males and 35 females, 44.5±12.7 year old) were compared with 63 normal age-, sex- and BMI-matched subjects.

The duration of disease ranged from 0.6 to 44 years (10.23±9.07 years). AD had received a cumulative dose of cortisone acetate of 290.5±326.8 g, equivalent to a daily dose of 44.5±15.5 mg, and to 26.34±10.57 mg/m² of body surface. AD had average values of both daily urinary cortisol excretion and salivary cortisol higher than controls (583±348 vs 374±184 nmol/24 h, and 15.5±11.2 vs 8.1±4.2 ng/ml, respectively; P<0.001 in both cases), suggesting that cortisone replacement was higher than the physiological dose.

Vertebral fracture were assessed by DXA morphometric analysis in 25 AD patients and 43 controls. For this purpose a Hologic Discovery W device was used with a specific software for the vertebral height measurement. Eight patients showed at least one vertebral morphometric fracture, while only three subjects showed morphometric fractures in the control group (odds ratio=6.27; 95% CI=1.48–26.57; P=0.013).

Despite the higher number of vertebral fractures, AD showed densitometric variables similar to those of the control group in any evaluated area, including lumbar spine, femoral neck and whole body. Body composition (lean and fat body mass, expressed both in grams and in percent of total body mass) is similar in the two groups. Concerning laboratory parameters, daily calcium excretion is lower in AD patients than in controls (3.35±2.32 vs 5.21±2.38 mmol/24 h; P=0.0001). The other biochemical variables, including serum calcium and phosphate, bone alkaline phosphatase, serum CTx, 25OH vitamin D, 1,25(OH)2 vitamin D and PTH were similar in the two groups. No correlations were found between urinary cortisol excretion, salivary cortisol, duration of disease, cumulative and daily dose of replacement therapy and either laboratory or densitometric parameters in AD patients.

In conclusion, AD patients showed a risk of vertebral morphometric fractures higher than normals. Such risk does not seem to be related to a lower bone density or to common alterations of mineral metabolism, suggesting that fractures could be related to qualitative alterations of bone structure and the concomitant endocrine deficiency.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.