Bone Abstracts

Objective: Of this study was to investigate the factors influencing fractures in endogenous Cushing’s syndrome (CS) of various etiologies.

Materials and methods: The retrospective data of patients, who had received treatment due to endogenous CS, (2001–2011 years) was evaluated. All enrolled patients underwent standard spinal radiographs in lateral positions of the vertebrae Th4-L4. Recent low traumatic non-vertebral fractures were recorded in the medical cards. Bone mineral density (BMD) was measured by DXA GE Lunar Prodigy. Serum samples on octeocalcin (OC), carboxyterminal cross-linked telopeptide of type I collagen (CTx)), late-night cortisol in serum, adrenocorticotropin (ACTH) were assayed by electrochemiluminescence (ECLIA). 24 h urinary free cortisol (UFC) was measured by an immunochemiluminescence assay (extraction with diethyl ether).

Results: Among 215 patients, 178 were females and 37 males, median age 35 (Q25–Q75 27–48); 88 patients (40.9%) had low traumatic fractures, including vertebral fractures in 76 cases (in 60 cases multiple vertebral fractures) and non-vertebral fractures in 27 cases (17 patients had ribs fractures, three fractures of metatarsal bones, two fractures of radius, two fractures of tibia and fibula, 1 – humerus, 1 – breastbone; 2 – hip fractures). Patients with fractures had higher 24 h UFC, late-night cortisol in serum, ACTH, lower OC, total hip and spine BMD, but did not differ in age, BMI, CTx or etiology of CS. After applying the logistic regression analysis (adjusted for sex, age, BMI, BMD, OC), the main predictor of fractures was 24 h UFC level (P=0.02) and a separately analyzed late-night serum cortisol level (P=0.001). Patients with late-night serum cortisol higher than 597 nmol/l were more likely to have low traumatic fractures (odds ratio 2.86 (95% CI 1.55–5.28) P=0.001)

Conclusions: The severity of hypercortisolemia is the best predictor of low traumatic fractures in patients with CS. Patients with higher levels of late-night serum cortisol might need earlier preventive treatment for osteoporosis.