Inadequacy of Ferritin Trends for Predicting Changes in LIC Risk Category in Transfusion Depedent and Well Chelated Patients with Haemoglobinopathies

Introduction. Chronic iron overload may represent a serious complication of potentially lifesaving blood transfusions in different haematological diseases. Excess iron deposits in various tissues of the body, particularly the liver, heart, and endocrine organs (Cappellini. Thalassaemia International Federation, 2014). This process leads to tissue damage and ultimately to significant morbidity and mortality (Musallam. Haematologica 2013). Indeed, organ failure due to chronic iron overload may represent the major cause of death in patients with different haematological diseases who receive blood transfusions regularly without appropriate chelation therapy (Inati. Pediatr Blood Cancer 2011; N Engl J Med 2000; Cleve Clin J Med 2005). The main aim of this study was to look for the relationships between changes in LIC and changes in serum ferritin (SF) level, during real life experience with larger setting of patients with haematological diseases and different chelation regimens, previously described at baseline, according to the LICNET protocol (Vitrano et al., Eur J Haematol 2016).

Methods. This was a cross-sectional study of patients with haematological disorders attending 9 Italian centres participating in the LICNET. The LICNET protocol was approved on December 4, 2012 by our Ethical Committee. The underlying diagnoses were regularly transfused Thalassemia Major (TM), Thalassemia Intermedia (TI), Sickle Cell Disease (SCD), Myelodysplastic Syndrome (MDS), Diamond-Blackfan Anemia (DBA). Transfused status was defined as receipt of ≥7 mL/kg/month of packed red blood cells. The inclusion criteria for the cross-sectional analysis were: 1) underlying diagnosis above described; 2) determination of two R2-MRI scans performed as part of the network, for those patients presenting between February 2013 and December 2016; 3) transfusion dependence; 4) same chelation treatment at T0 (MRI1) and T1 (MRI2) . The settled R2-MRI protocol at the Centre follows that of St Pierre et al. (St Pierre et al. Magn Reson Med 2014). Descriptive analysis was provided as means, standard deviations, medians or percentages. Three classes of risk (low, intermediate and high), on the basis of LIC values ( <7mg Fe/g dry weight (dw), 7-15 mg Fe/g dw, >15 mg Fe/g dw ) were considered to evaluate the control of iron body burden during the study period. LIC comparisons at MRI1 and MRI2 were made using t -test and/or Wilcoxon test. All p -values are two sided with the level of significance set at <0.05.

Results. A total of 130 patients were evaluated, with a median age of 35 years (range: 6-78). The median duration (range) between MRI1 and MRI2 days was 483 (184-1076). Patients' characteristics for the considered chelation regimens are summarized in Table 1. Overall patients, across all chelation regimens, showed a statistically significant difference in variation of LIC between MRI1 and MRI2 (p=0.011, Table 2). Overall variation of LIC, during a period of 483 (184-1076) days, was -0.8 (-29.0-33.0) mg Fe/g dw. Median changes in LIC (range), mg Fe/g dw for single chelation regimen are reported on Tab. 2. Changes in LIC determinations, during the period of the study, according to the baseline values, are shown on Fig. 1: Overall 7.7% of patients, across different chelation regimens and during a period of 483 (184-1076) days, moved from high risk group (LIC >15 mg Fe/g dw) to intermediate risk group (LIC 7-15 mg Fe/g dw) with stabilization of iron overloading in patients in low risk group at baseline; all chelation regimens were able to move LIC from high risk group to intermediate risk group. In the other combination group, the patients moved from the intermediate risk group to the low risk group. Median changes in SF level (range), ng/ml for overall patients and for single chelation regimen are reported on Tab. 2: Overall patients, across all chelation regimens, did not show any statistically significant difference in variation of SF between MRI1 and MRI2 (p= 0.566, Table 2).

Conclusions. In conclusion, SF level trends are unable to predict changes in LIC, even in well chelated patients with haematological disorders. Therefore, variations of SF level must be interpreted with caution and confirmed, when it is possible, by direct measurement of LIC for more correct management of chelation treatment.

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