Associations between OD, GD and epidemiological outcomes
Patients with hypertension had a low proportion of OD than those without hypertension (74.9% versus 88%; p=0.001). Females had higher prevalence of subjective total loss of smell compared with males (74.2versus 65.3%; p=0.001). However, males had a higher proportion of partial loss of smell compared with females (19.2 versus13.7%; p=0.001). Cacosmia was more prevalent in females compared with males (67.9 versus 61.7%; p=0.018). Findings were similar for GD (58.4 versus 53.4%; p=0.038). Moreover, 18.7% and 9.7% of females and males reported total loss of aroma sense, respectively (p=0.001). Note that aroma perception was distorted in 15.7 and 15.6% of females and males, while 11.3% females and 18.1% males did not report AD (p=0.001).
Considering patients with psychophysical olfactory testing, we found significant positive associations between the score of Sniffin’Sticks tests and the patient age (rs=0.246; p<0.001); fever severity (rs=0.210; p=0.004), cough (rs=0.212; p=0.003), dyspnea (rs=0.243; p=0.001) and asthenia (rs=0.225; p=0.002); all of these symptoms being more prevalent in patients with moderate and severe-to-critical COVID-19 forms. There was a statistical trend for females to have a lower Sniffin’Sticks test result compared with males (9.7±4.1 versus 10.8±3.6; p=0.05). The subjective perception of loss of smell was positively associated with the results of the objective olfactory test (p<0.001). In other words, patients who reported OD had a higher probability to be anosmic or hyposmic at the psychophysical tests. There was a significant association between Sniffin’s Sticks tests and self-reported AD. Anosmic and hyposmic patients reported more frequently AD (p<0.001). There was no significant association between Sniffin’sticks test results and SNOT-22 items and total score.