Clinical Features of Olfactory Dysfunction in COVID-19 Patients

Min Young Seo, Won Suk Choi, Seung Hoon Lee
2021 Journal of Korean medical science  
The aim of this study was to evaluate the subjective and objective olfactory function in coronavirus disease 2019 (COVID-19) patients and the effect of olfactory training. A prospective cohort study was performed in 53 patients who recovered from COVID-19 and visited our tertiary hospital. Subjective olfactory function was evaluated using the 11-point Likert scale (0-10) and the Korean version of the Questionnaire of Olfactory Disorders (QOD). Objective olfactory function was evaluated using
more » ... ss-Cultural Smell Identification Test (CC-SIT). Confirmed patients were followed up after 2 months of olfactory training. The median, interquartile range (Q1-Q3) score of subjective olfactory function significantly deteriorated in patients with olfactory dysfunction (OD) than in those without OD, even after 3 months of onset (11-point Likert scale, 8, 6-9 vs. 10, 10-10; short version of QOD-negative statements, 19, 16-21 vs. 21, 21-21; QOD-visual analogue scale, 7, 1-13 vs. 0, 0-0; all P < 0.001). However, the objective olfactory function was not significantly different between the two groups (median, interquartile range; 11, 9-11 vs. 11, 9-11, P = 0.887). The percentage of patients with objective hyposmia (CC-SIT ≤ 10) was also not significantly different (47.4% vs. 40%, P = 0.762). OD in COVID-19 was normalized after 2 months of olfactory training in 70% of patients even after 3 months of olfactory impairment. Although subjective olfactory function is significantly decreased in the OD group, the objective olfactory function was not significantly different. Moreover, olfactory training is effective in COVID-19 patients with OD.
doi:10.3346/jkms.2021.36.e161 pmid:34100564 pmcid:PMC8185125 fatcat:5wj7a3dx4ze7jj3zozlt7z7nem