A brief version of the questionnaire of olfactory disorders in patients with chronic rhinosinusitis

Background The Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS) is a valuable instrument in the measurement of olfactory-specific quality of life (QOL). In the clinical setting, patients can be overwhelmed with the time required to complete questionnaires. Our objective was to develop a brief version of the QOD-NS to streamline clinical care and research. Methods QOD-NS scores from 221 subjects were used to determine which subset of the 17 QOD-NS questions best correlated with total and subdomain QOD-NS scores. An initial pool of 11 questions was made by removing items with rho < 0.80 to their respective subdomain scores. Next, 500 bootstrapped samples were taken. On each sampe, an all-subsets regression was performed with total QOD-NS scores and QOD-NS subdomain scores as the outcomes. From this, our top and bottom 10 subsets were identified based on mean r(2) value, representation in bootstrap analysis, and number of items. Results All of our top subsets had excellent correlation with total and subdomain QOD-NS scores (mean r(2) > 0.90). Our top choice has 7 total questions, is representative of all subdomains, has a mean r(2) = 0.92, and was represented in 323 of our 500 bootstrapped samples. The worst-performing subset has 5 items, mean r(2) = 0.81, and was represented in only 1 bootstrapped sample. Conclusions Using less than half of the questions in the QOD-NS, excellent correlations with both total and domain-specific scores are achieved. A brief version of the QOD-NS may prove useful in future clinical and research settings.