Olfactory dysfunction in COVID-19, new insights from a cohort of 353 patients: The ANOSVID study

Area of Science:

• Neurology
• Infectious Diseases
• Otorhinolaryngology

Background:

• The pathogenesis, underlying conditions, and prognosis of olfactory disorders (OD) in coronavirus disease 2019 (COVID-19) are not fully understood.
• Olfactory dysfunction is a common symptom of COVID-19, but its association with patient characteristics and comorbidities requires further investigation.

Purpose of the Study:

• To compare COVID-19 patients with and without olfactory disorders (OD).
• To analyze the association between the severity of OD (anosmia vs. hyposmia) and patient comorbidities.
• To identify symptoms associated with OD in COVID-19 patients.

Main Methods:

• Retrospective study (ANOSVID) of COVID-19 patients at Nord Franche-Comté Hospital (March-May 2020).
• Comparison between COVID-19 patients with OD (OD group) and without OD (no-OD group).
• Second analysis comparing patients with anosmia (high OD group) and those with hyposmia or no OD (low or no-OD group).

Main Results:

• The OD group had fewer cardiovascular and respiratory diseases compared to the no-OD group (OR=0.536, p=0.041 and OR=0.222, p=0.037).
• History of malignancy was less frequent in the high OD group (OR=0.170, p<0.001).
• Associated symptoms with OD included loss of taste (OR=24.059, p<0.001) and cacosmia (OR=5.821, p<0.001); headache and facial pain increased in the high OD group.
• The high OD group showed higher creatinine clearance (89.0±21.1 vs. 81.0±20.5, p=0.040).
• No significant differences in virological, radiological, or severity criteria were found.

Conclusions:

• COVID-19 patients with OD appear to have fewer comorbidities, particularly better cardiovascular and renal function.
• Neurological symptoms like headache and facial pain are significantly associated with OD in COVID-19.
• Methodological limitations may have precluded finding a relationship between OD and COVID-19 severity.