History of Myocardial Iron Loading is a Strong Risk Factor for Diabetes Mellitus and Hypogonadism in Adults with β Thalassemia Major

Endocrinopathies are common complications of transfusional hemosiderosis among patients with β thalassemia major (TM). Previous studies had shown associations between some endocrinopathies and iron overload of the myocardium, liver and/or endocrine organs as assessed by MRI techniques. This retrospective analysis of 92 patients with TM (median age 36 yr) from a tertiary adult thalassemia unit in UK aimed to determine independent risk factors associated with endocrinopathies among these patients. Unlike previous studies, longitudinal data on routine measurements of iron load [worst myocardial and liver T2* values since 1999, worst LIC by MRI-R2 since 2008 and average 10-yr serum ferritin (SF)] up to April 2010 together with demographic features and age of initiating chelation were analyzed for associations with endocrinopathies. The most common endocrinopathies in this cohort were hypogonadism (67%) and diabetes mellitus (DM) (41%), and these were independently associated with myocardial T2* <20 ms (P < 0.001 and P = 0.008, respectively) and increased age (P = 0.002 and P = 0.016, respectively). DM and hypogonadism were independently associated with average SF >1250 μg/L (P = 0.003) and >2000 μg/L (P = 0.047), respectively. DM was also associated with initial detection of abnormal myocardial T2* at an older age (30 yr vs. 24 yr, P = 0.039). An abnormal myocardial T2* may therefore portend the development of DM and hypogonadism in patients with TM.