Responsiveness and convergent validity of the chronic rhinosinusitis patient‐reported outcome (CRS‐PRO) measure in CRS patients undergoing endoscopic sinus surgery
Katherine A. Lin, Caroline P.E. Price, Julia Huang, Saied Ghadersohi, David Cella, Robert C. Kern, David B. Conley, Stephanie S. Smith, Kevin C. Welch, Bruce K. Tan
Abstract
BACKGROUND: The chronic rhinosinusitis patient-reported outcome (CRS-PRO) measure is a 12-item measure with previously demonstrated validity in chronic rhinosinusitis (CRS) patients receiving medical therapy. This study establishes the factor structure, responsiveness, and convergent validity of the CRS-PRO following endoscopic sinus surgery (ESS). METHODS: Northwestern CRS Subject Registry patients had pre-ESS, 3-month (n = 111; CRS without nasal polyps [CRSsNP] = 60, CRS with nasal polyps [CRSwNP] = 51), and 6-month (n = 86; CRSsNP = 47, CRSwNP = 39) post-ESS assessments where patients completed the CRS-PRO, 22-item Sino-Nasal Outcome Test (SNOT-22), and four Patient-Reported Outcomes Measurement (PROM) Information System (PROMIS) short forms (general health measures). Patients had pre-ESS objective testing (endoscopic and radiographic assessment). Factor analysis was conducted using principal axis factoring with varimax rotation on the baseline CRS-PRO. The clinically important difference (CID) was estimated using both distribution-based and anchor-based methods. RESULTS: Factor analysis found the CRS-PRO comprised the "rhino-psychologic," "facial discomfort," and "cough" factors, which were responsive to ESS and correlated with the other PROMs. The changes observed in the CRS-PRO at 3 months had strong correlation with the corresponding changes in SNOT-22 (r = 0.792, p < 0.0001) and moderate correlations with changes in PROMIS fatigue and sleep domains. These changes had a very large effect size (Cohen's d 1.44) comparable to the longer SNOT-22 (Cohen's d 1.41) with slightly larger effect sizes observed in CRSwNP compared to CRSsNP patients. Similar convergent validity and responsiveness were observed in the 6-month data. The CRS-PRO CID was estimated to be between 5.0 and 7.5 (midpoint 6.0) using distribution-based and anchor-based methods. CONCLUSION: This study demonstrates the validity and responsiveness of the CRS-PRO in subjects receiving ESS.