TY - JOUR
T1 - One-year psychophysical evaluation of COVID-19-induced olfactory disorders
T2 - a prospective cohort study
AU - Schepens, Emma J. A.
AU - Boek, Wilbert M.
AU - Boesveldt, Sanne
AU - Stokroos, Robert J.
AU - Stegeman, Inge
AU - Kamalski, Digna M. A.
N1 - Funding Information: The study team thanks and acknowledges all patients for their participation in this study. Special thanks to C. de Haas, K. Krommenhoek, and N. Maagdenberg for their help with conducting the psychophysical tests. This publication is part of the COVID-19 program and forms a component of the project Sniffing Out COVID with Project Number 10430102110001, funded by the Dutch Organization for Health Research and Development (ZonMw). Publisher Copyright: © 2023, The Author(s).
PY - 2023/12/1
Y1 - 2023/12/1
N2 - Background: Olfactory disorders are common in COVID-19. While many patients recover within weeks, a notable number of patients suffer from prolonged olfactory disorders. Much research has focused on the acute phase of olfactory disorders in COVID-19; however, there is still inconsistency regarding the prognosis. We aim to assess both objective and subjective olfactory function in patients with persisting olfactory disorders following COVID-19, 1 year after diagnosis. Methods: We objectively measured olfactory function in 77 patients who initially had COVID-19-induced smell disorders, 1 year after confirmed diagnosis. These patients previously underwent two objective measurements at approximately 3 and 6 months after COVID-19, in the context of the COCOS trial (COrticosteroids for COvid-19-induced loss of Smell). The main outcome measurement was TDI score (threshold-discrimination-identification) on Sniffin’ Sticks Test (SST). Secondary outcomes included objective gustatory function on Taste Strip Test (TST), self-reported olfactory, gustatory and trigeminal function on a visual analogue scale (VAS) and outcomes on questionnaires about quality of life, and nasal symptoms. Results: The findings of this study show that 1 year following COVID-19, the median TDI score increased to 30.75 (IQR 27.38–33.5), regarded as normosmia. The median TDI score started at 21.25 (IQR 18.25–24.75) at baseline and increased to 27.5 (IQR 23.63–30.0) at 6 months following COVID-19. The increase of 9.5 points on the TDI score between baseline and 1 year after COVID-19 marks a clinically relevant improvement. Regarding the self-reported VAS score (1–10) on sense of smell, it increased from 1.2 (IQR 0.4–3.0) at baseline to 3.2 (IQR 1.4–6.0) at 6 months and further improved up to 6.1 (IQR 2.7–7.5) after 1 year. Objective gustatory function increased with 2 points on TST a year after diagnosis. Self-reported olfactory, gustatory, and trigeminal functions also improved over time, as did quality of life. Conclusions: Objective and self-reported olfactory function continued to improve 1 year after COVID-19. The median TDI score of 30.75 (IQR 27.38–33.5) is regarded as normosmia, which is a favorable outcome. However, the rate of improvement on TDI score reduces over time.
AB - Background: Olfactory disorders are common in COVID-19. While many patients recover within weeks, a notable number of patients suffer from prolonged olfactory disorders. Much research has focused on the acute phase of olfactory disorders in COVID-19; however, there is still inconsistency regarding the prognosis. We aim to assess both objective and subjective olfactory function in patients with persisting olfactory disorders following COVID-19, 1 year after diagnosis. Methods: We objectively measured olfactory function in 77 patients who initially had COVID-19-induced smell disorders, 1 year after confirmed diagnosis. These patients previously underwent two objective measurements at approximately 3 and 6 months after COVID-19, in the context of the COCOS trial (COrticosteroids for COvid-19-induced loss of Smell). The main outcome measurement was TDI score (threshold-discrimination-identification) on Sniffin’ Sticks Test (SST). Secondary outcomes included objective gustatory function on Taste Strip Test (TST), self-reported olfactory, gustatory and trigeminal function on a visual analogue scale (VAS) and outcomes on questionnaires about quality of life, and nasal symptoms. Results: The findings of this study show that 1 year following COVID-19, the median TDI score increased to 30.75 (IQR 27.38–33.5), regarded as normosmia. The median TDI score started at 21.25 (IQR 18.25–24.75) at baseline and increased to 27.5 (IQR 23.63–30.0) at 6 months following COVID-19. The increase of 9.5 points on the TDI score between baseline and 1 year after COVID-19 marks a clinically relevant improvement. Regarding the self-reported VAS score (1–10) on sense of smell, it increased from 1.2 (IQR 0.4–3.0) at baseline to 3.2 (IQR 1.4–6.0) at 6 months and further improved up to 6.1 (IQR 2.7–7.5) after 1 year. Objective gustatory function increased with 2 points on TST a year after diagnosis. Self-reported olfactory, gustatory, and trigeminal functions also improved over time, as did quality of life. Conclusions: Objective and self-reported olfactory function continued to improve 1 year after COVID-19. The median TDI score of 30.75 (IQR 27.38–33.5) is regarded as normosmia, which is a favorable outcome. However, the rate of improvement on TDI score reduces over time.
KW - COVID-19
KW - Olfactory disorders
KW - Prognosis
KW - Smell
UR - http://www.scopus.com/inward/record.url?scp=85178919753&partnerID=8YFLogxK
U2 - https://doi.org/10.1186/s12916-023-03205-x
DO - https://doi.org/10.1186/s12916-023-03205-x
M3 - Article
C2 - 38066629
SN - 1464-2662
VL - 21
JO - BMC medicine
JF - BMC medicine
IS - 1
M1 - 490
ER -