Is the Persian Version of the "Olfactory Disorder Questionnaire" Reliable and Valid?

Abstract

The Questionnaire for Olfactory Dysfunction (QOD) is a self-reporting olfactory-related quality of life questionnaire. The aim of this study was to determine the reliability and validity of the Persian version of this questionnaire. One hundred and thirteen patients with olfactory problems were enrolled in this study. The English version of the QOD was first translated into Persian. The reliability was then tested by determining the Cronbach alpha coefficient to assess internal consistency. The QOD was reviewed by a panel of experts, followed by calculating the content validity index to determine the content validity. Based on the reliability analysis, the total Cronbach alpha was 0.88. The items in the "life quality" and "parosmia" domains had a good internal consistency in total, as well as in both genders and in different age subgroups. For the "sincerity" domain, however, low internal consistency was revealed (Cronbach alpha = 0.25). When questions related to the sincerity domain were omitted, the Cronbach alpha reached 0.89. The overall scale validity index for clarity and relevance were 0.88 and 0.87, respectively. The Persian version of the QOD seems to be a reliable and valid tool for the assessment of quality of life in patients with olfactory dysfunction. The "sincerity" domain cannot be used separately or should be substantially modified in order to be applicable to the Iranian population. However, there is no need to change the whole format of the questionnaire.