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 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 36yr) 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* <20ms (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 >1250g/L (P=0.003) and >2000g/L (P=0.047), respectively. DM was also associated with initial detection of abnormal myocardial T2* at an older age (30yr vs. 24yr, P=0.039). An abnormal myocardial T2* may therefore portend the development of DM and hypogonadism in patients with TM.