Does Medical Therapy Improve SinoNasal Outcomes Test-22 Domain Scores? An Analysis of Clinically Important Differences.

OBJECTIVES/HYPOTHESIS: Minimum clinically important differences (MCIDs) for the 22-item SinoNasal Outcomes Test (SNOT-22) in patients with chronic rhinosinusitis (CRS) electing endoscopic sinus surgery (ESS) are well described. However, similar estimations for the MCID have not been investigated for patients electing continued appropriate medical therapy (CAMT). We sought to determine MCID values for a medically treated CRS cohort and compare them to historical MCIDs associated with ESS. STUDY DESIGN: Prospective observational cohort study. METHODS: One hundred twenty patients with refractory CRS electing CAMT were prospectively enrolled from academic referral clinics into an observational cohort study. Baseline and posttreatment SNOT-22 survey responses were collected. Four distribution-based methods for calculating MCIDs (e.g., half-standard deviation, Cohen's d, standard error of measurement, and minimum detectable change) were used to identify a range of MCID values for SNOT-22 total and domain scores. RESULTS: The average MCID value for SNOT-22 total scores was 8.0, whereas mean MCID values for rhinologic, extranasal rhinologic, ear/facial, psychological, and sleep symptom domain scores were 3.9, 2.5, 3.3, 3.4, and 2.9, respectively, comparable to previously reported values for patients electing ESS. Although change in SNOT-22 total scores following CAMT exceeded the MCID, none of the average SNOT-22 domain score improvements surpassed their respective MCID thresholds. CONCLUSIONS: MCID values for SNOT-22 total and domain scores in patients electing CAMT are similar to previously published MCID values associated with ESS, indicating that MCID values are independent of treatment modality selection. Therefore, despite evidence of statistical significance, CAMT for CRS may not be associated with clinically discernable improvements in average SNOT-22 domain scores. LEVEL OF EVIDENCE: 2c Laryngoscope, 129:31-36, 2019.