Position paper on olfactory dysfunction: 2023

BACKGROUND: Since publication of the original Position Paper on Olfactory Dysfunction in 2017 (PPOD-17), the personal and societal burden of olfactory disorders has come sharply into focus through the lens of the COVID-19 pandemic. Clinicians, scientists and the public are now more aware of the importance of olfaction, and the impact of its dysfunction on quality of life, nutrition, social relationships and mental health. Accordingly, new basic, translational and clinical research has resulted in significant progress since the PPOD-17. In this updated document, we present and discuss currently available evidence for the diagnosis and management of olfactory dysfunction. Major updates to the current version include, amongst others: new recommendations on olfactory related terminology; new imaging recommendations; new sections on qualitative OD and COVID-19 OD; updated management section. Recommendations were agreed by all co-authors using a modified Delphi process. CONCLUSIONS: We have provided an overview of current evidence and expert-agreed recommendations for the definition, investigation, and management of OD. As for our original Position Paper, we hope that this updated document will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency, and generalisability of work in this field.

Developing a core outcome set for clinical trials in olfactory disorders: a COMET initiative.

STATEMENT OF PROBLEM: Evaluating the effectiveness of the management of Olfactory Dysfunction (OD) has been limited by a paucity of high-quality randomised and/or controlled trials. A major barrier is heterogeneity of outcomes in such studies. Core outcome sets (COS) - standardized sets of outcomes that should be measured/reported as determined by consensus-would help overcome this problem and facilitate future meta-analyses and/or systematic reviews (SRs). We set out to develop a COS for interventions for patients with OD. METHODS: A long-list of potential outcomes was identified by a steering group utilising a literature review, thematic analysis of a wide range of stakeholders' views and systematic analysis of currently available Patient Reported Outcome Measures (PROMs). A subsequent e-Delphi process allowed patients and healthcare practitioners to individually rate the outcomes in terms of importance on a 9-point Likert scale. RESULTS: After 2 rounds of the iterative eDelphi process, the initial outcomes were distilled down to a final COS including subjective questions (visual analogue scores, quantitative and qualitative), quality of life measures, psychophysical testing of smell, baseline psychophysical testing of taste, and presence of side effects along with the investigational medicine/device and patient's symptom log. CONCLUSIONS: Inclusion of these core outcomes in future trials will increase the value of research on clinical interventions for OD. We include recommendations regarding the outcomes that should be measured, although future work will be required to further develop and revalidate existing outcome measures.

Incidence and duration of self-reported hearing loss and tinnitus in a cohort of COVID-19 patients with sudden chemosensory loss: A STROBE observational study.

AIMS: To investigate the self-reported audiological symptoms in a cohort of coronavirus disease 2019 (COVID-19) patients and monitor improvement or recovery. MATERIAL AND METHODS: Following the STROBE guidelines for observational studies, a retrospective questionnaire concerning audio-vestibular symptoms was conducted in a cohort of Danish COVID-19 patients with self reported chemosensory loss. Data regarding demographics, symptoms onset, duration and remission was registered in a REDCap database. RESULTS: Of the 225 respondents with chemosensory loss, 59 (26.2%) reported concomitant hearing loss (10.7%) or tinnitus (16.4%). In a follow-up questionnaire focused on ear-symptoms, severity, and duration (n=31), 17 reported hearing loss and 21 reported tinnitus. Debut of hearing loss and tinnitus were on average 10 and 30 days respectively, after onset of initial symptoms. Among the hearing loss patients, only two patients experienced full recovery, whereas 15 had partial or no recovery after on average 266 days from COVID-19 symptom onset. Among the tinnitus patients, 7/21 had full recovery, while 14 had partial or no recovery after on average 259 days from COVID-19 symptom onset. CONCLUSION: In a large Danish cohort of COVID-19 patients, a significant proportion experienced concomitant audiological symptoms which seem long lasting and with negative impact on quality of life. This study warrants further investigation of the association between COVID-19 and audio-vestibular symptoms, and the need for rehabilitation among convalescents.