الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
Thalassemia is one of the most challenging diseases being faced by mankind with virtually no permanent treatment for those who suffer from it. The only real treatment is periodical replenishment of blood through transfusion.
Osteopenia and osteoporosis are major causes of morbidity in patients with B-thalassemia, who today survive longer as a result of improved treatment. Recently, osteoprotegerin (OPG), a secreted member of the tumor necrosis factor receptor superfamily, has been identified as an osteoblast-derived regulator of bone resorption. OPG acts by neutralizing receptor activator of the nuclear factor k-B ligand (RANKL), an essential cytokine required for osteoclast formation and activation. Two recent studies have shown that the ratio of OPG/RANKL is decreased in patients with thalassemia and osteoporosis, providing evidence for the role of the OPG/RANKL system in the pathogenesis of osteoporosis in these patients.
This study was carried out aiming to characterize the possible role of the OPG/RANKL system in thalassemic patients suffering from osteoporosis. This was intended to be achieved through assessment of serum OPG level and serum RANKL level in thalassemic patients and detecting the relation between OPG/RANKL system and development of osteoporosis and comparing these results with healthy individuals.
The study design was comparative cross sectional study and was carried out among 29 thalassemic and another 29 normal subjects matching patients for age and sex.
Both groups were matched regarding age and sex. In both groups the studied patients were in age group ranging from 9 to 25 years old with mean age 17.3 in thalassemic group and 17.7 in control group (p-value > 0.05).
Anemia was significantly reported among thalassemic patients with mean Hb value equals 6.89 g/dl versus 12.8 g/dl in control group (p-value < 0.05). Serum calcium was found to be significantly lower among thalassemic patients, while serum phosphorus and alkaline phosphatase were found to be higher among thalassemic patients (p-value < 0.05). Blood glucose level was within the normal range among both study groups without statistically significant difference (p-value > 0.05). ALT was found to be significantly higher among thalassemic patients (p-value < 0.05).serum Albumin concentration was within normal ranges among both groups with no statistically significant difference.
OPG/RANKL ratio was significantly lower among thalassemic group. This difference can be ascribed to OPG more than RANKL as it was found that RANKL values were not statistically significant among the two study groups while OPG was found to be significantly lower among the thalassemic patients.
No one of the control groups has osteoporosis while only 17.2% has osteopenia. In the thalassemic group 65.5% has either osteopenia or osteoporosis. This difference between the study groups was statistically significant.
Thalassemic patients with normal bone density showed significantly higher OPG and OPG/RANKL ratio when compared to thalassemic patients suffering from osteopenia and osteoporosis. Meanwhile, RANKL values were not statistically significant among both groups of the study.
OPG/RANKL ratio was found to be insignificantly correlated to all other laboratory markers.
62.1% of the thalassemic patients are HCV positive. However, statistically insignificant, the incidence of osteoporosis was numerically more with HCV positive patients (27.8% versus 9.1% with HCV negative patients; p-value > 0.05). Differences between HCV positive and HCV negative thalassemic patients regarding OPG, RANKL and OPG/RANKL ratio were statistically insignificant (p-value > 0.05).
ROC curve analysis showed that an OPG value ≤ 1.5 can be used to detect osteopenia/osteoporosis among thalassemic patients with 67% sensitivity (95% CI = 44.7 – 84.3) and 76% specificity (95% CI = 58.8 – 89.2) and an OPG/RANKL ratio ≤ 0.95 can be used to detect the presence of osteopenia/osteoporosis with 80% sensitivity (95% CI = 57.8 – 92.8) and 65% specificity (95% CI = 46.5 – 80.2).
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