Responsiveness and Convergent Validity of a New Patient-Reported Outcome Measure for Chronic Rhinosinusitis (CRS-PRO)

Background: The CRS-PRO is a new patient-reported outcome measure (PROM) for chronic rhinosinusitis (CRS) that was developed using extensive patient input per Food and Drug Administration guidance on PROMs acceptable for use as end points in clinical trials. Objective: To assess the responsiveness and convergent validity of the CRS-PRO following standard-of-care medical therapy. Methods: This was a prospective study of 51 patients (21 with nasal polyps and 30 without) with newly diagnosed CRS or having an acute CRS exacerbation who were initiated on appropriate medical therapy. At the baseline visit each patient completed the CRS-PRO questionnaire, the 22-item Sino-Nasal Outcome Test, the EuroQol 5-dimensional questionnaire, and 4 Patient-Reported Outcome Measure Information System short forms along with objective testing including endoscopic and radiographic scores, smell discrimination, and nasal inspiratory flow testing. This same battery of questionnaires and testing was administered at a follow-up visit 4 to 8 weeks later. Results: We verified that shortening the 21-item CRS-PRO to 12 items as previously described maintains its psychometric properties. The 12-item CRS-PRO was responsive with a large effect size (Cohen's d, 0.94) comparable to the longer 22-item Sino-Nasal Outcome Test (Cohen's d, 0.93). The instrument was slightly more responsive to medically treated patients with CRS without nasal polyps compared with patients with CRS with nasal polyps (Cohen's d, 1.1 vs 0.89, respectively). The change in 12-item CRS-PRO total score has moderate correlation with change in Lund-Mackay computed tomography scores. Conclusions: The CRS-PRO is a 12-item rigorously developed, responsive, and valid PROM that was developed using extensive input from patients with current definitions of CRS, including its 2 major phenotypes.