BACKGROUND: This cross-sectional, multi-centric study aimed to investigate the differences in quality of life among patients with olfactory dysfunction (OD) of different origin, and to identify factors associated with olfactory-related quality of life (QOL). METHODS: Seven hundred sixty-three adults were recruited from 8 Smell & Taste clinics in Germany, Switzerland, and Austria. Olfactory-related QOL was assessed by the Questionnaire of Olfactory Disorders (QOD). Olfactory function was assessed with the “Sniffin’ Sticks” test; self-assessment was performed with visual analog scales. RESULTS: Patients with post-infectious and post-traumatic OD showed poorer olfactory-related QOL than patients with sinonasal and idiopathic OD. The olfactory-related QOL was positively associated with the Sniffin’ Sticks test score, self-assessed olfactory function, disease duration, and age, with younger olfactory dysfunction patients showing lower QOL. Female patients presented with poorer olfactory-related QOL. In addition, the results showed that self-assessment of olfactory function explained more of the variance in olfactory-related QOL than olfactory function evaluated by the Sniffin’ Sticks test. CONCLUSIONS: In addition to the psychophysical testing results, several factors such as disease cause, disease duration, sex, or self- assessed olfactory dysfunction should be taken into account when assessing the individual severity of the smell loss.

Background: The aim of this study was to determine the reliability and validity of the brief version of Questionnaire of Olfactory Disorders (brief QOD). Methods: A total of 372 patients participated in this study. Olfactory function was examined using the Sniffin’ Sticks test. The brief version of QOD, including 4 items concerning parosmia (QOD-P), 7 items concerning quality of life (QOD-QOL), and 3 visual analog scales to rate disease burden, awareness of the disorder and issues related to professional life (QOD-VAS), was used to assess subjective information on olfactory dysfunction. We evaluated the split-half reliability, internal consistency and validity of the brief QOD. Results: The split-half reliability was 0.60 (QOD-P), 0.87 (QOD-QOL), and 0.66 (QOD-VAS), respectively. The Cronbach’s α coefficient was 0.63 (QOD-P), 0.87 (QOD-QOL), and 0.71 (QOD-VAS), respectively. Olfactory function was found to be associated with QOD-P, QOD-QOL and QOD-VAS. Conclusions: The brief QOD is a suitable scale for the assessment of subjective severity of olfactory dysfunction for purposes such as treatment counseling, disability assessment, treatment control, and research in patients with olfactory disorder.