Assesment of 25 HydroxyVitaminD Level and Bone Mineralization Status in Children and Adolescents with Beta Thalassemia Major in Relation to Different Chelation Therapies

Abstract

SUMMARY T halassemia patients require blood transfusions, experience growth failure and developmental problems as it affects multiple organs and is associated with considerable morbidity and mortality amongst which is bone disease. The Spectrum of bone abnormalities in TM patients includes osteopenia, osteoporosis, pain, fractures and spinal complications and represents prominent causes of morbidity in children and adults of both genders with TM. Vitamin D deficiency is quite common in thalassaemia major patients’ due to increased metabolic demands, chronic medical care, and iron overload or parathyroid hypofunction. Treatment of patients with thalassemia major consists of regular blood transfusions and iron chelation therapy, which is vital to prevent excess iron buildup in the body. There are three iron chelating agents available: deferoxamine (DFO, Desferal), an iron chelator given by infusion, and two oral chelatorsdeferiprone (DFP, Ferriprox) and deferasirox (DFX, Exjade). Treatment with iron chelators has significantly increased the life expectancy of affected individuals into the third to fifth decade. The aim of this study was to assess the level of 25 hydroxy vitamin D and bone mineralization status in β-thalassemic patients and its relation to different types of chelation therapies to compare the effect of sc chelators versus recent oral chelators on bone mineralization status. Our study included 45 patients with β-thalassemia major who were following up regularly in the Pediatric Hematology clinic of the Pediatric Hospital, Ain Shams University. Patients were subdivided into 3 equal groups according to chelation therapy. Group (1) included patients on desferrioxamine, group (2) patients were on deferiprone and group (3) patients were on deferasirox. They were compared with 15, age and sex matched, healthy children and adolescents controls.All patients were subjected to full history taking and thorough clinical examination with stress on: age at diagnosis, frequency of blood transfusion, splenectomy, chelation therapy, and bone related symptoms and signs. Complete blood count, levels of 25-OH-vit D, serum calcium, serum phosphorous, serum alkaline phosphatase and serum ferritin were measured. In our study, hemoglobin level was significantly lower in our patientsthancontrols. Serum Ca. and 25 –OH-vit D were significantly lower in our patients than controls, 70 % of patients had low serum Ca. and 25 –OH-vit D levels. 30% had normal levels. Regarding phosphorous level; we found that there is no significant difference between patients and controls. The serum alkaline phosphatase level was significantly higher in our patients than that of controls. No significant difference was found between patients subgroups as regards hemoglobin level, bone markers and 25 –OH- VitD. Our study populations were moderate to severely iron overloaded with no significant difference in s.Ferritin and compliance to chelation therapy between patients subgroups. Serum Ca. and 25 –OH-vit D were significantly lower in Female patients than male patients was no significant difference in other parameters like WBC, Hb level, PLT, phosphorous level, alkaline phosphatase and s.Ferritin were found between them. There was no significant difference in the effect of sc.chelators and oral chelators on hemoglobin level, bone markers, 25 –OH- VitD and s.Ferritin. 25 (OH) vit D correlated proportionately with serum calcium; and inversely with serum ferritin. There was no significant correlation between 25 (oh) vit D and other parameters like weight, height, WBC, Hb level and PLT.