Risk factors for heart disease in transfusion-dependent thalassemia: serum ferritin revisited

Heart disease remains a leading cause of morbidity and mortality in transfusion-dependent thalassemia (TDT), which can be attributed to several factors but primarily develops in the setting of iron overload. This was a retrospective cohort study utilizing Webthal (R) patient data from five major centers across Italy. Patients without heart disease were followed-up for 10 years (2000-2010) and data were collected for demographics, splenectomy status, serum ferritin and hemoglobin levels, and comorbidities associated with heart disease. Among 379 patients analyzed (mean age 22.9 +/- 5.1years, 47.8% men), 44 (cumulative incidence: 11.6%) developed heart disease during the period of observation. Splenectomy (p=0.002) and serum ferritin level (p<0.001) were the only risk factors with significant association with heart disease. A serum ferritin threshold of >= 3000 ng/mL was the best predictor for the development of heart disease (86.4% sensitivity and 92.8% specificity, AUC: 0.912, 95% CI 0.852-0.971, p<0.001). On multivariate analysis, only a serum ferritin level >= 3000 ng/mL remained significantly and independently associated with increased risk of heart disease (HR: 44.85, 95% CI 18.85-106.74), with a 5- and 10-year heart disease-free survival of 58 and 39%. The association between iron overload and heart disease in patients with TDT is confirmed, yet a new serum ferritin level of 3000 ng/mL to flag increased risk is suggested.