Endocrinopathies, metabolic disorders, and iron overload in major and intermedia thalassemia: serum ferritin as diagnostic and predictive marker associated with liver and cardiac T2* MRI assessment

Abstract

Introduction: Endocrinopathies and metabolic disorders-characterized β thalassemic (βT) patients and the prevention and treatment of these comorbidities are important targets to be achieved. The aim of the study was to analyze the diagnostic and prognostic role of ferritin for endocrinopathies and metabolic disorders in βT patients. The ability of iron chelators to treat iron overload and to prevent or reverse metabolic disorders and endocrinopathies was also evaluated.

Patients and methods: Seventy-two βT patients were treated with different chelation strategies during the study. Receiver operating characteristics analysis was employed to calculate the area under the curve for serum ferritin to find the best cutoff values capable of identifying endocrine dysfunction in thalassemic patients. Kaplan-Meier curves were generated to assess the incidence of endocrinopathy. Adjusted risk estimates for endocrinopathy were calculated using univariate followed by multivariate Cox proportional hazard regression analysis.

Results: High ferritin levels were observed in patients with hypothyroidism [1500 (872.5-2336.5) μg/L], hypogonadism [878 (334-2010) μg/L], and in patients with hypoparathyroidism or osteoporosis [834 (367-1857) μg/L]. A strict correlation between ferritin and T2* magnetic resonance imaging of heart (r = -0.64; P:0.0006) and liver (r = -0.40; P:0.03) values was observed. Patients with ferritin values above 1800 μg/L experienced a significantly faster evolution to hypothyroidism [log-rank (χ(2) ):7.7; P = 0.005], hypogonadism [log-rank (χ(2) ):10.7; P = 0.001], and multiple endocrinopathies [log-rank (χ(2) ):5.72; P = 0.02]. Ferritin predicted high risk of endocrine dysfunction independently of confounding factors (HR:1.23; P < 0.0001). The intensification of chelation therapy led to an amelioration of hypothyroidism.

Conclusions: Ferritin represents a prognostic marker for βT patients and a predictive factor for progression to endocrine dysfunctions. Intensive chelation therapy allows the reversibility of hypothyroidism.

Keywords: endocrinopathies; ferritin; hypothyroidism; iron chelation therapy; magnetic resonance imaging; thalassemia.