Subjective and Objective Olfactory Dysfunctions
Among the patients with OD, 1,545 (59.9%) and 356 (13.8%) reported
that the OD consisted of partial or total loss of smell. The prevalence
of subjective OD in mild, moderate and severe-to-critical patients was
85.3% (N=1,847), 21.5% (N=31) and 7.4% (N=20), respectively
(p=0.001). Cacosmia and phantosmia were reported in 63.6%
(N=1,427/2,242) and 14.1% (N=316/2,242) of cases. Irrespective to
disease severity, the subjective OD developed before (14.6%), during
(25.4%) or after (55.0%) the other symptoms. The mean duration time of
OD was 11.5±5.7 days.
Among the 2,579 patients, 231 patients benefited from Sniffin’Sticks
tests, including 181 mild, 23 moderate and 27 severe-to-critical
individuals. The median time between the onset of OD and the realization
of psychophysical evaluation was 18 days. The mean Sniffin’Stick test
was 10.5±3.7. There were 75 anosmic, 43 hyposmic and 113 normosmic
patients, corresponding to a prevalence of objective OD of 51.0% (Table
3). The mean SNOT-22 at the time of the olfactory assessment was
33.5±20.7. Among the 50 moderate or severe-to-critical COVID-19
patients, 7 and 12 had hyposmia and anosmia, corresponding to a
prevalence of objective OD of 38%. In the 181 mild patients, there were
63 anosmic and 36 hyposmic individuals, respectively. The prevalence of
objective OD in mild patients was 54.7%. The proportion of anosmic and
hyposmic patients was significantly higher in mild patients compared
with moderate-to-critical patients (p=0.001).