Impact of chelation therapy on serum zinc levels in transfusion dependent thalassaemia patients

Background: Children with thalassaemia major receive regular blood transfusions, which can lead to iron deposition due to the absence of excretory mechanisms. To overcome this, chelating agents like deferasirox (DFX), deferiprone (DFP), and deferoxamine (DFO) are used which affect zinc levels. Zinc deficiency in thalassaemia patients may cause immunodeficiency, aberrant haematopoiesis and delay in growth and development.
Objectives: Measurement of serum zinc levels in children with transfusion-dependent thalassaemia (TDT) receiving chelating agents.
Method: This cross-sectional study analysed 77 registered children with TDT in Sri Guru Ram Das Institute of Medical Sciences and Research, Sri Amritsar, India, without zinc supplementation for last 3 months. Data were collected through detailed history and chelation therapy details. Zinc levels were measured using atomic absorption spectrometry.  
Results: Of 73 (94.8%) children with TDT who were on chelation therapy, 35 (47.9%) were only on DFX chelation, 37 (50.7%) were receiving a combination of DFX+DFP and one (1.4%) patient was receiving a combination of DFO+DFX. In the DFX group, the mean serum zinc level was 77.1+14.13µg/dL which was significantly higher when compared to the mean serum zinc level in DFX+DFP group which was 58.3+7.38µg/dL and DFO+DFX where the mean serum zinc value was 38.4 µg/dL (p value <0.01). Zinc had significant negative correlation with the duration of chelation with correlation coefficient r=-0.231 and p value 0.049.
Conclusions: Children with thalassaemia who were on more than one chelating agent had lower serum zinc levels. Zinc had significant negative correlation with the duration of chelation.