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).