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Thalassemia, adrenal insufficiency, pitfall in the diagnosis, ACTH stimulation test, guidelines.
Introduction: In March 2015, the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescent Medicine (ICET-A) implemented a two-step survey on central adrenal insufficiency (CAI) assessment in TM patients and after analysis of the collected data, recommendations for the assessment of hypothalamic-pituitary- adrenal (HPA) axis in clinical practice were defined.
Methods: To ascertain the current practice for assessment of CAI in thalassemia, the Coordinator of ICET-A sent two questionnaires by email: i) The first to evaluate the current interpretation of basal serum cortisol level (first step) and ii) The second to evaluate the current usage of ACTH test and the variability in practice" (second step). Based on the surveys the core ICET-A group prepared the recommendations for the assessment of suspected CAI in thalassemia (third step).
Results: A total of 19 thalassemologists/endocrinologists have participated in the first survey and 35 specialists participated in the second step questionnaire. The survey demonstrated a considerable variability in almost all aspects of relevant current criteria used for the diagnosis of CAI. A ROC analysis using peak value > 20 ?g/dl (> 550 nmol/L), after ACTH stimulation test, was performed with the aim of identifying the optimal basal serum cortisol cut-off. The optimal threshold that maximizes sensitivity plus specificity for morning basal cortisol against peak post-ACTH value >20 ?g/dl (>550 nmol/L) was 10 ?g/dl (275 nmol/L).,Furthermore, the values associated with highest negative predictive value (NPV) and highest, positive predictive value (PPV) were 4.20 (115 nmol/L) and 18.45 ?g/dl (510 nmol/L), respectively.
Surprisingly, 20 specialists in thalassemia working in blood bank, thalassemia centres (day hospital), internal medicine, hematology and onco-hematology had poor knowledge and experience in testing for CAI and stopped filling the questionnaire after the second question. In contrast, 9 endocrinologists (8 pediatricians) and 6 hematologists working in collaboration with endocrinologists completed the questionnaire.
Conclusions: While waiting more extensive adequately powered and targeted studies, physicians should adopt an acceptable policy for accurate assessment of HPA in TM patients. Regular surveillance, early diagnosis, treatment and follow-up in a multi-disciplinary specialized setting are also recommended. The ICET-A recommendations are reported in order to facilitate for interested physicians the approach to successful assessment of adrenal function in thalassemia.
Key words: Thalassemia, adrenal insufficiency, pitfall in the diagnosis, ACTH stimulation test, guidelines.