VALUTAZIONE DELLA FUNZIONE SURRENALICA IN PAZIENTI ADULTI AFFETTI DA ΒETA-TALASSEMIA

Better transfusion and chelation regimens have changed the natural history of β-thalassaemia from high pediatric mortality to survival well into adulthood. On the other hand, increased survival led to the development of additional disorders and endocrinopathies rank among the most frequent long-term complications in thalassaemic patients. Only scant information is available on adrenocortical function in these patients, thus the risk of insufficient cortisol secretion in response to stressful events is unknown. Aims of the present study were a) to estimate the prevalence of adrenocortical insufficiency in a large series of adult thalassaemic patients; b) to explore the usefulness of salivary cortisol for the diagnosis of adrenocortical insufficiency; c) to establish the impact of this endocrinopathy on the quality of life of patients with thalassaemia. We recruited 72 patients (44 women, 28 men, age range 25-60 years) and measured serum and salivary cortisol after 1 μg ACTH stimulation test. All patients were administered SF-36 Health Survey for assessment of quality of life. Subnormal serum cortisol responses to ACTH stimulation (i.e., <18 μg/dl) were registered in 14 patients (19%). Salivary cortisol increased in parallel with serum cortisol at all timepoints and a clear-cut positive correlation between both parameters was detected (r = 0.478, p<0.001 for peak cortisol). Peak salivary cortisol values after ACTH stimulation were significantly lower in patients with impaired adrenal reserve (0.7 ± 0.29 vs 1.3 ± 0.47 μg/dl, p<0.005) and proved good predictors of adrenocortical insufficiency at ROC analysis (Youden index J 0.693, 95% confidence interval 0.474; 0.855). Physical (PCS) and mental (MCS) health scores were below average in thalassaemic patients per se (PCS 47.1% ± 1.12; MCS 47.8% ± 1.36) without significant differences between patients with impaired or preserved adrenal reserve. In conclusion, our study demonstrates that a significant proportion of adult thalassaemic patients present impaired adrenal reserve and underlines the need for testing for adrenal insufficiency in these patients. Serum and salivary cortisol levels during ACTH stimulation were closely correlated and salivary cortisol may represent a surrogate to serum cortisol for testing in thalassaemic patients.