Endocrine and bone disease in appropriately treated adult patients with beta-thalassemia major.

With the optimization of transfusional and chelation regimens, beta-thalassemia has changed from a pediatric disease with poor life expectancy into a chronic disease. Bone demineralization is an important cause of morbidity in older patients; the etiology is multifactorial and partially unknown. We examined, cross-sectionally, 111 adult patients with beta-thalassemia major (66 females and 45 males, 32.6 ± 6 years) who were regularly transfused, sufficiently chelated and replaced for endocrine defects. Bone demineralization was detected in 92.7% of patients with different severity according to gender and site: osteopenia was the prominent finding at the femur, osteoporosis at the lumbar spine (p < 0.001), more evident in males. The femoral site was more influenced by biochemical and clinical factors; despite adequate replacement, the femoral T-score was lower in the hypogonadic group than in the eugonadic group (p = 0.047). A significant correlation was found between the bone mass and body mass index (BMI), alkaline phosphatase (ALP), and pre-transfusional Hb levels. The multivariate analysis indicated as significant regressors ALP, BMI and hypoparathyroidism (T-score, p = 0.005, 0.035, and 0.002; Z-score, 0.002, 0.009, and 0.003, respectively) at the femoral site; whereas, only ALP at the lumbar spine (p = 0.008 and 0.045 for T-and Z-scores, respectively). The statistical significance was reached more frequently by the T-score, while the Z-score seemed to be a less sensitive parameter. Despite best care facilities, bone demineralization in thalassemic patients remains a challenge. Further exploration of the relationships between bone loss and endocrine, biochemical and hematologic parameters is warranted to find effective measures to reduce the risk of fracture in this disease.

Bone demineralization in adult thalassaemic patients: contribution of GH and IGF-I at different skeletal sites.

BACKGROUND AND OBJECTIVE: GH and IGF-I exert an important role in the control of bone formation, as shown by decreased bone mineral density and increased fracture risk in adult hypopituitary patients untreated for GH deficiency (GHD). Different degrees of bone demineralization are frequently reported in patients affected by beta-thalassaemia. Considering the high prevalence of GHD recently observed by our group among adult thalassaemic patients, we elected to study the possible role of GH-IGF-I abnormalities in the pathogenesis of the osteopenia/osteoporosis of this disease. DESIGN: Sixty-four adult thalassaemic patients (49 with thalassaemia major and 15 with thalassaemia intermedia, 23 men and 41 women, aged 31.4 +/- 6.8 years) were studied. METHODS: Bone mineral density was assessed by dual energy X-ray absorptiometry at lumbar spine in 62 patients and at proximal femur in 58. All patients underwent GHRH (1 microg/kg as an i.v. bolus) plus arginine (0.5 g/kg as a 30-min i.v. infusion) testing. Severe GHD was defined by GH peaks < 9 microg/l, whereas partial GHD was defined by GH peaks ranging from 9 to 16.5 microg/l. Blood samples for IGF-I measurement were collected. RESULTS: Lumbar osteoporosis and osteopenia were demonstrated in 46/62 (74.1%) and 14/62 (22.5%) patients, respectively. Femoral osteoporosis and osteopenia were documented in 22/58 (37.9%) and 32/58 (55.1%) patients, respectively. Severe GHD was demonstrated in 16/64 patients (25%), while 11 additional patients (17.1%) displayed partial GHD. IGF-I standard deviation score (SDS) was low, that is, below -1.88, in the majority (54.6%) of patients. Lumbar T-score values were not correlated with either GH peaks or IGF-I SDS values. Femoral T-score values were positively correlated with GH peaks (r = 0.38, P < 0.005) and IGF-I SDS values (r = 0.39, P < 0.005). Multiple regression analysis pointed to both GH peak and IGF-I SDS as predictors of femoral T-score. Furthermore, mean femoral T-score was significantly lower in patients with severe GHD than in those with normal GH secretion (-2.94 +/- 0.25 vs.-2.15 +/- 0.12, P < 0.01). CONCLUSION: This study, while confirming the high prevalence of both osteopenia/osteoporosis and somatotropin-somatomedin deficiency in adult thalassaemic patients, indicates that defective GH secretion and diminished serum IGF-I levels may contribute to femoral demineralization in these patients. Further studies are worth carrying out to evaluate the efficacy of biosynthetic GH administration on bone abnormalities of GH-deficient thalassaemic adults.