LOW-TRAUMATIC FRACTURES IN PATIENTS WITH ENDOGENOUS HYPERCORTISOLISM. PREDICTORS AND RISK FACTORS, THE IMPACT ON QUALITY OF LIFE

Abstract

The objective of this study was to investigate the prevalence of low traumatic fractures, the factors influencing fractures in endogenous Cushing’s syndrome (CS) of various etiologies and their contributions into functional abilities and quality of life in patients with CS. Materials and methods: the retrospective data of patients, who had received treatment due to endogenous CS, (2001-2011), 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), latenight cortisol in serum were assayed by electrochemiluminescence (ECLIA). 24h urinary free cortisol (24hUFC) was measured by an immunochemiluminescence assay (extraction with diethyl ether). Functional assessment was performed using «chair rising», «up and go» and «tandem» tests. Universal pain assessment tool (verbal descriptor scale, Wong-Baker facial grimace scale, activity tolerance scale), EQ-5D and ECOS-16 questionnaires were given to patients and they self-reported their conditions. Results: Among 215 patients, 178 were females and 37 males, median age 35 (Q25-Q75 27-48); 88patients (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 rib fractures, 3 -fractures of metatarsal bones, 2 fractures of radius, 2 fractures of tibia and fibula, 1 humerus, 1 breastbone; 1 hip fracture). Patients with fractures had higher 24hUFC, late-night cortisol in serum, lower OC, Total Hip 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 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). Patients with fractures suffered from more pain and reported worse functional abilities. They had slightly worse results in «tandem» test, but did not differ in other functional tests, which assessed mainly muscle power. Conclusions: Patients with CS have very high risk of low traumatic fractures. The severity of hypercortisolemia is the best predictor of low traumatic fractures in patients with CS. Patients with fractures sufferedfrom more severe pain and because of this they restricted their daily activity even more than patients with CS without fractures. Consequently, patients with higher levels of late-night serum cortisol need earlier preventive treatment for osteoporosis.