Hypothyroidism and Cardiac Complications In Thalassemia Major Patients

Abstract

Abstract Introduction In the non-thalassemic population hypothyroidism has been associated with an increased risk of cardiac disease while the link thyroid-heart disease has been little explored in thalassemia major (TM). This retrospective cohort study aimed to systematically evaluate in a large historical cohort of TM in the cardiovascular magnetic resonance (CMR) era whether hypothyroidism was associated with a higher risk of heart complications (heart failure, arrhythmias and pulmonary hypertension). Methods From a cohort of 957 TM patients who underwent CMR for myocardial iron overload (MIO) assessment, quantification of biventricular function and detection of myocardial fibrosis within the MIOT network (Myocardial Iron Overload in Thalassemia), we identified 115 (12%) hypothyroid patients. Each hypothyroid patient was matched by sex and age (at the time of the CMR) with two non-hypothyroid patients, creating 115 triples. A cardiac event was considered valid if diagnosed at an age older than the hypothyroidism’s onset age for the hypothyroid patient in the belonging triple. Results Hypothyroid and non-hypothyroid patients had comparable MIO, but hypothyroid patients showed significantly lower biventricular stroke volume index, ejection fraction and left ventricular cardiac index. Accordingly, the prevalence of overall heart dysfunction (LV, RV or both) was higher in hypothyroid patients (43.5% vs 33.5%, P=0.0314). Hypothyroid patients had a significant higher frequency of heart failure (19.1% vs 9.1%, P=0.003) and arrhythmias (11.3% vs 4.3%; P=0.003). Figure1 shows odds ratios (OR) estimating the relationship between hypothyroidism and cardiac involvement. Hypothyroid patients had a significant higher risk of heart dysfunction, heart failure and arrhythmias, also adjusting for the endocrine co-morbidity. Conclusions Hypothyroidism seems to increase the risk for heart failure, arrhythmias and heart dysfunction in TM patients. Our data confirm the link thyroid-heart disease also in TM patients and they stress the need to prevent hypothyroidism in this population. Disclosures: No relevant conflicts of interest to declare.