Objective and subjective olfactory dysfunction among COVID-19 inpatients
and controls: a prospective, case-control study
Abstract
Introduction: Olfactory dysfunction associated with COVID-19 infection
is frequently described, but few studies utilize validated, objective
tests or a control group. We compared rates of olfactory dysfunction
between adults hospitalized with COVID-19 and controls admitted with
similar upper respiratory symptoms who were COVID-19-negative. Methods:
Hospitalized (general ward) adults with upper respiratory symptoms who
tested PCR positive or negative for SARS-CoV-2 completed the objective
Brief Smell Identification Test (BSIT; ≥9 correct=normal) and subjective
assessments while hospitalized and again at 3 month follow up.
Comparison of groups was performed by t test or chi-square test of
independence. Results: There were no differences in mean age or gender
between groups (n=26 COVID, n=28 control). Both groups demonstrated
objective olfactory dysfunction (mean BSIT 7.9 ± 2.8 COVID vs. 8.3 ± 3.2
control, p=0.62). Rates of both objective and subjective dysfunction did
not significantly differ between groups. Follow up data at 3 months was
limited (n=6 COVID, n=5), but showed 50% olfactory dysfunction in COVID
patients compared to 20% in controls. Conclusions: SARS-CoV-2 and other
viral illnesses serious enough to cause hospitalization cause olfactory
dysfunction. Better understanding of the trajectory of chemosensory
recovery will help elucidate the pathophysiology of viral-associated
olfactory dysfunction and inform the care of patients suffering from its
sequelae.