The COVANOS trial – insight into post-COVID olfactory dysfunction and the role of smell training

Lechner, Matt, Liu, Jacklyn, Counsell, Nicholas, Gillespie, David C., Chandrasekharan, Deepak, Hong Ta, Ngan, Jumani, Kiran, Rao, Sri V., Rocke, John, Williams, Claire, Tetteh, Abigail, Amnolsingh, Rajesh, Khwaja, Sadie, Batterham, Rachel, Yan, Carol H., Treibel, Thomas A., Moon, James C., Woods, Jane, Brunton, Ria, Boardman, Jim, Paun, Santdeep, Eynon-Lewis, Nicholas, Kumar, B. Nirmal, Jayaraj, Samuel, Hopkins, Claire, Philpott, Carl ORCID: https://orcid.org/0000-0002-1125-3236 and Lund, Valerie J. (2022) The COVANOS trial – insight into post-COVID olfactory dysfunction and the role of smell training. Rhinology, 60 (3). pp. 188-199. ISSN 0300-0729

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Abstract

Background: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. Methodology: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. Results: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. Conclusions: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.

Item Type: Article
Additional Information: Funding Information: The study was funded by the Rhinology and Laryngology Research Fund, GSST charity and WWL charity. TAT is funded by a BHF Intermediate Research Fellowship (FS/19/35/34374). JCM, TAT and ML are directly and indirectly supported by the UCLH and Barts NIHR Biomedical Research Units.
Uncontrolled Keywords: covid-19,anosmia,olfactory training,parosmia,quality of life,otorhinolaryngology ,/dk/atira/pure/subjectarea/asjc/2700/2733
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
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Depositing User: LivePure Connector
Date Deposited: 11 Mar 2022 13:30
Last Modified: 04 Oct 2022 12:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/83996
DOI: 10.4193/Rhin21.470

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