Endocrine Abstracts

Adult GHD patients may have reduced BMD with high risk of vertebral and non-vertebral fractures which is thought to be reverted by long-term rhGH replacement therapy. In this study we aimed at identifying the determinant factors of vertebral fractures, as assessed by a radiological morphometric approach, in a cohort of adult patients with untreated GHD. Forty-two patients (27 males, 15 females; median age: 48 years, range: 30–67) with untreated severe (as defined by a peak GH response to a stimulation test of <3 μg/l) GHD were evaluated for vertebral deformities (T4-L5 quantitative morphometric analysis according to Genant score) and bone mineral density (dual-energy X-ray absorptiometry). Radiological vertebral fractures were found in 33 patients (78.6%). Twenty-two patients had two or more fractures, whereas in 11 patients the fractures were single. Moreover, the fractures were mild in 54.8%, moderate in 19.0% and severe in 7.1% of patients. Fractured patients had a duration of GHD significantly longer as compared with the patients who were found without vertebral fractures (10.4±1.9 vs 3.4±0.9 years; P=0.002). The duration of GHD was also correlated with the number of fractures. Fractured and non-fractured patients showed not significant differences in age, sex, bone mineral density, prevalence of untreated hypogonadism. Moreover, fractured and non-fractured patients showed comparable serum IGF-I values (79.3±6.9 ng/ml vs 89.7±12.3 ng/ml). However, serum IGF-I values were correlated with the number of vertebral fractures, independently of the duration of GHD. In fact, in the patients with lower serum IGF-I values (1st tertile) the prevalence of multiple spinal fractures was significantly greater as compared to patients with higher IGF-I values (3rd tertile; 76.9% vs 33.3%; P=0.01), although the two groups of patients did not show significant differences in the overall prevalence of vertebral deformities (86.7% vs 73.3%). Furthermore, the patients with severe spinal fractures showed significantly lower IGF-I values as compared to patients with mild spinal deformities (39.7±15 ng/ml vs 90±7.6 ng/ml; P=0.009). In conclusion, in adult patients with untreated GHD the duration of disease seems to be the main predictor of vertebral fracture risk. However, patients with lower serum IGF-I levels are those at risk of a more severe bone impairment.