Outcome measures for chronic rhinosinusitis with nasal polyps

Background: With the recent proliferation of novel therapeutics for chronic rhinosinusitis with nasal polyps (CRSwNP), there is an immediate need for comprehensive means to assess CRSwNP disease status as well as to determine treatment efficacy. Outcome measures exist in different forms. Patient-reported outcome measures (PROMs) allow patients to provide direct input about their condition that is not possible to obtain in any other way. Common constructs that are measured using PROMs include quality of life or the burden of disease manifestations (e.g., symptom severity). Outcomes may also include the results of objective diagnostic testing/measurement of clinical signs or measured using psychophysical tests. Biomarkers represent an emerging class of outcome measures for CRSwNP and are chosen to directly reflect the active pathophysiologic processes of CRSwNP in the peripheral blood, sinus/polyp tissues, and sinonasal mucus. Methods: Narrative review of the literature, identifying and describing outcome measures that may be used in the evaluation of CRSwNP and for assessment of treatment responses. Results: In this review, we identify many different outcome measures for CRSwNP that fall under the categories of PROM, objective test, psychophysical test or biomarker. We describe the history of each - including seminal studies - and demonstrate the formal validation, psychometric performance, and limitations of each. Conclusions: PROMs, objective tests, psychophysical tests and biomarkers represent different classes of outcome measures that are complementary means of assessing CRSwNP disease status and treatment efficacy. The choice or interpretation of a CRSwNP outcome measure should be undertaken with full knowledge of its formal validation, psychometric performance, and limitations.