Liver iron concentration is an independent risk factor for the prediabetic state in β-thalassemia patients

Abstract

Beta-thalassemia major (β-TM) comprises a group of inherited blood disorders characterized by the reduced synthesis of β-globin chains. Iron overload following blood transfusion can affect major tissues involved in glucose metabolism, leading to different glucose metabolic disorders in these patients. The aim of the present study was to compare glucose metabolism and iron overload indices in β-TM patients with prediabetic and normoglycemic states. This analytical study was performed on 49 patients with β-TM (age > 18 years), receiving regular blood transfusions. The fasting plasma glucose (FPG) and glucose tolerance tests indicated 32 normoglycemic and 17 prediabetic cases. The serum levels of C-peptide, fructosamine, fasting serum insulin, and serum ferritin were measured. In addition, T2*-weighted magnetic resonance imaging (MRI) of the heart and liver was carried out. Glycemic metabolism indices, including quantitative insulin sensitivity check index (QUICKI) and homeostatic model assessment for insulin resistance (HOMA-IR), were also calculated. The HOMA-IR score was significantly higher, while the QUICKI score was significantly lower in prediabetic patients, compared to normoglycemic patients (median [IR], 2.59 [2.19] vs. 1.46 [1.03], p = 0.007; mean ± SD, 0.34 ± 0.03 vs. 0.37 ± 0.04, p = 0.01). On the other hand, β-cell function was not significantly different between the groups. The liver iron concentration (LIC) at a cutoff point of 5.82 mg/g dry weight showed 93% sensitivity and 70% specificity for differentiation of prediabetic and normoglycemic states (AUC, 0.81 [95% CI, 0.65–0.95]; p = 0.002). Based on the findings, HOMA-IR and QUICKI can be applied as useful glycemic metabolism indices for predicting prediabetic and normoglycemic states among β-TM patients. Also, LIC was an independent risk factor for the prediabetic state.