“…In order to explain this heterogeneity, different outcome studies that considered various possible prognostic factors have been conducted so far [4,5,6,7,8,9,10]. In particular, age at onset, age at index treatment, history of an eating disorder (ED), duration of the disease and BMI at onset have been considered, often with conflicting results [3,8,9,11,12,13,14,15,16]. Contrasting findings may be due to methodological differences related to the lengths of follow-up, psychopathological and clinical assessment, retrospective data collection, varying subgroup criteria and different kinds of treatment taken into account [12,17,18].…”