Analysis of the influence of iron overload in glucose metabolism in thalassemia major patients

Abstract

Objective: This study aimed at determining the characteristics of the glucose homeostasis and its relationship with iron overload of the patients with β-thalassemia major (β-TM). Method: From Sun Yat-sen Memorial Hospital between January 2014 and December 2015, a total of 57 transfusion-dependent β-TM patients with 5-18 years old were enrolled in this study and fasting blood glucose(FBG) and insulin level, serum ferritin (SF), serum iron, transferrin, total iron binding capacity, unsaturated iron binding capacity were determined.Insulin resistance index (IRI), insulin sensitivity index and β-cell function index (BFI) were also estimated. Besides, in 36 patients cardiac T2* and liver T2* were estimated. Result: (1) Four patients(7%) with β-TM were diagnosed diabetes mellitus, and 14(24%) had impaired fasting glucose. (2) The incidence of abnormal glucose metabolism was significantly different according to levels of SF and degrees of the cardiac iron overload(χ(2)=9.737, P<0.05; χ(2)=17.027, P<0.05). It rose while the level of SF increased and the degree of cardiac iron overload aggravated. (3) The incidence of abnormal glucose level was not significantly different in cases with different degree of liver iron overload.The severe group of liver iron overload had significantly higher levels of INS, HOMA-βFI, HOMA-ISI, HOMA-βFI than the non-severe group (Z=-2.434, -2.515, F=8.658, all P<0.05), while no differences were found in the level of FBG, HOMA-βFI between two groups. (4) The result of logistic regression analysis indicated that the cardiac T2* was a significant predictor for the incidence of abnormal glucose metabolism in TM patients (P=0.035, OR=1.182%, 95%CI=1.048 to 1.332). Conclusion: The high prevalence of abnormal glucose metabolism in β-TM patients was mainly closely related with the internal iron overload, especially in organs.The cardiac T2* was an independent risk factor for the incidence of abnormal glucose metabolism in TM patients.