Patient-reported outcomes in cystic fibrosis.

Over the past 20 years, there has been tremendous progress in the area of patient-reported outcomes (PROs). A PRO instrument is defined as any measure of a patient's health status that is elicited directly from the patient and assesses how the patient "feels or functions with respect to his or her health condition." The advances seen in clinical research regarding PROs has been mirrored in research in cystic fibrosis (CF). A large number of instruments have been used for both therapeutic and nontherapeutic clinical research for many chronic conditions. This review will summarize a history of the development of PROs and how PROs are viewed by the U.S. Food and Drug Administration. We will then review the current state of the art of patient-reported outcomes in CF, specifically addressing the evaluation of different PRO instruments in terms of their reliability and validity. Finally, we will delineate further areas for development of PROs in CF. We believe that the future of CF research will incorporate a more diverse selection of PRO outcome measures; these outcome measures ultimately may be incorporated into clinical care to standardize symptom assessment and provide information regarding the need for specific clinical interventions to improve the quality of care delivered to these patients.