A patient-reported outcome (PRO) is a measure of the experience or view of a participant in a clinical study. It is not a clinical measure, or an assessment made by anyone else involved in the study. PROs are commonly collected by asking patients to fill in questionnaires, or by interviewing patients. Questionnaires or interview guides used as part of clinical studies should undergo extensive testing to ensure they are reliable and valid.
PROs can be used to assess, for example, symptoms as experienced by the patient, disability, quality of life, and other health perceptions.
There are many published PRO questionnaires dealing with aspects of quality of life. some have been developed for specific conditions or treatments. Some are designed to be general, such as the 'EuroQoL' or 'EQ-5D', which has been translated into many languages and used extensively in clinical trials.
PRO is often used interchangeably with the term patient-reported outcome measure (PROM).