Development and Validation of the Parosmia Olfactory Dysfunction Outcomes Rating (DisODOR)

Objective. Develop and validate a quality-of-life (QoL) outcome measure for patients with dysosmia.Study Design. Cross-sectional survey study.Setting. Otolaryngology clinics, research registries, and Facebook support groups.Methods. A 59-item pilot survey with questions addressing parosmia concerns was developed using input from subjects with parosmia and clinical expertise from Otolaryngologists. After item reduction, the Parosmia Olfactory Dysfunction Outcomes Rating (DisODOR) was reduced to its final 29 items. DisODOR maximum score is 116 (each item score 0-4) with higher scores indicating a higher degree of dysfunction from smell distortion. DisODOR was validated using participants with parosmia persisting >3 months after severe acute respiratory syndrome coronavirus 2 (cases) and healthy controls. Reliability, face and content validity, internal consistency, convergent validity, discriminative validity, sensitivity to change, and the minimal clinically important difference (MCID) were assessed.Results. A total of 134 cases and 20 controls completed DisODOR. The mean (SD) age was 45.9 (12.2) for cases and 29.6 (8.9) for controls. The mean score difference between cases and controls was 45.0 (95% confidence interval, 40.5-49.5) displaying good discriminative validity. DisODOR showed strong test-retest reliability (r = .942) with high internal consistency (Cronbach's alpha = .971). DisODOR had a moderate correlation with SNOT-22 scores (r = .619) indicating good convergent validity. There is an excellent association with the global impression of severity categories (eta 2 = 0.447). Based on the distribution method, the MCID is 15.Conclusion. DisODOR is a valid, reliable QoL instrument for parosmia that can be used to measure the functional impact and QoL impairment for parosmia patients. DisODOR is sensitive to change and thus can be used in studies investigating treatments for parosmia.