[Patient-reported outcomes (PRO): historical profile, definitions, classifications and problems]

This contribution deals with the use, within healthcare systems, of patient-reported outcomes (PROs), i.e., all measures aimed at quantifying the state of health through the evaluation of outcomes reported by the patient himself. A survey of their cultural background, identified in the patient-centered model of medicine, is followed by a delineation of their historical profile (from 1914, the year of the first outcome measure, to the more recent examples of their use in clinical trial and practice), a classification based on the size they wish to detect and the reconstruction of the main lines of debate around their use in health care.