Hypogonadism, diabetes mellitus, hypothyroidism, hypoparathyroidism: incidence and prevalence related to iron overload and chelation therapy in patients with thalassaemia major followed from 1980 to 2007 in the Ferrara Centre

Abstract

273 patients with thalassaemia major followed from diagnosis in the Ferrara Centre were divided into 3 cohorts (C) according to the year of birth (C1=1954-1964, 85 patients; C2=1965-1974, 129 patients; C3=1975-2001, 59 patients) in order to study the trends of endocrine complications. Menarche occurred in 52 out of 112 patients (46%), without significant differences among the 3 groups, at the mean age of 13.9+/-1.4 years. Sixty-five percent of these patients had secondary amenorrhoea at the mean age of 18.8+/-3.7 years. In males complete pubertal development occurred in 48% of patients (C1:31%, C2: 44%, C3: 63%, p<0.05) followed by secondary hypogonadism in 24% of patients above 21 years of age. Primary (80%) and central 20%) hypothyroidism were diagnosed in 31% of patients (C1: 55%, C2: 31.5%, C3: 13.4%, p<0.05), diabetes mellitus (DM) in 17% of patients (C1: 28.6%, C2: 17.2%, C3: 3.4%, p<0.05), and hypoparathyroidism in 10.6% of cases (C1: 18.7%, C2: 10.1%, C3: 3.4%, p<0.05). No difference was found in patient mean age of diagnosis of hypothyroidism, DM or hypoparathyroidism (20.4+/-8.2 years, 19+/-5 yrs and 18.5+/-5.8 yrs respectively) but in all three groups age at diagnosis significantly increased over time (hypothyroidism and DM: p<0.001; hypoparathyroidism: p<0.01). Over time the prevalence of hypothyroidism, diabetes mellitus and hypoparathyroidism increased to 24.4%, 14.7%, and 6.7%, respectively, at the time of the study. Incidences peaked in the early 1980's, and declined in the following years (primary hypothyroidism from 6.5% in 1981 to 0.9% in 2007, p<0.01; DM from 3.9% in 1986 to 0.8% in 2007, p<0.05; hypoparathyroidism 2.4% in 1984 to 0% in 2007, p<0.01) and correlated with the decrease in annual mean serum ferritin levels in all patients (p<0.001). The main risk factors associated with endocrine complications were high serum ferritin levels, poor compliance with desferioxamine (DFO) therapy, early onset of transfusion therapy (only for hypogonadism) and splenectomy (only for hypothyroidism). Serum ferritin levels of approximately 2000 ng/ml were found to correlate with hypogonadism, and 3000 ng/ml for hypothyroidism, hypoparathyroidism and DM. The incidences of hypothyroidism, DM and hypoparathyroidism were not significantly different in 18 patients on long term treatment with deferiprone (DPO) compared with 64 patients continuously treated with DFO, from 1995 to 2007. In conclusion, our longitudinal study shows that in the last 30 years in the Ferrara Centre the incidences of hypothyroidism, diabetes mellitus, and hypoparathyroidism declined, and pubertal development in males with thalassemia major improved in patients, on DFO treatment, born after 1976. The efficacy of alternative chelation regimes with deferiprone or deferasirox to monotherapy with desferioxamine remains to be established.