Establishing utility values for the 22‐item Sino‐Nasal Outcome Test (SNOT‐22) using a crosswalk to the EuroQol–five‐dimensional questionnaire–three‐level version (EQ‐5D‐3L)

Background Chronic rhinosinusitis (CRS) is a common condition for which there are numerous medical and surgical treatments. The 22‐item Sino‐Nasal Outcome Test (SNOT‐22) is a patient‐reported outcome measure often used with patients diagnosed with CRS. However, there are no utility values associated with the SNOT‐22, limiting its use in comparative effectiveness research. The purpose of this study was to establish utilities for the SNOT‐22 by mapping responses to utility values associated with the EuroQol–5‐dimensional questionnaire–3‐level version (EQ‐5D‐3L). Methods This study used data collected from patients diagnosed with CRS awaiting bilateral endoscopic sinus surgery in Vancouver, Canada. Study participants completed both the SNOT‐22 and the EQ‐5D‐3L. Ordinary least squares was used for 3 models that estimated the EQ‐5D‐3L utility values as a function of the SNOT‐22 items. Results A total of 232 participants completed both the SNOT‐22 and the EQ‐5D‐3L. As expected, there was a negative relationship between the SNOT‐22 global scores and EQ‐5D‐3L utility values. Adjusted R 2 for the 3 models ranged from 0.28 to 0.33, and root mean squared errors between 0.23 and 0.24. A nonparametric bootstrap analysis demonstrated robustness of the findings. Conclusion This study successfully developed a mapping model to associate utility values with responses to the SNOT‐22. This model could be used to conduct comparative effectiveness research in CRS to evaluate the various interventions available for treating this condition.