Olfactory and gustatory dysfunctions in COVID-19 outpatients: A prospective cohort study

Objectives: To describe the characteristics, evolution and risk factors for long-term persistence of olfactory and gustatory dysfunctions (OGD) in COVID-19 outpatients.

Patients and methods: We conducted a prospective study in SARS-CoV-2 infected outpatients with OGD. Weekly phone interviews were set up starting from COVID-19 onset symptoms and over the course of 60 days, using standardized questionnaires that included a detailed description of general symptoms and OGD. The primary outcome was the proportion of patients with complete recovery of OGD at D30. Rate and time to recovery of OGD, as well as risk factors for late recovery (>30 days), were evaluated using Cox regression models.

Results: Ninety-eight outpatients were included. The median time to onset of OGD after first COVID-19 symptoms was 2 days (IQR 0-4). The 30-day recovery rate from OGD was 67.5% (95% CI 57.1-75.4) and the estimated median time of OGD recovery was 20 days (95% CI 13-26). Risk factors for late recovery of OGD were a complete loss of smell or taste at diagnosis (HR=0.26, 95% CI 0.12-0.56, P=0.0005) and age over 40 years (HR=0.56, 95% CI 0.36-0.89, P=0.01).

Conclusions: COVID-19 patients with complete loss of smell or taste and over age 40 are more likely to develop persistent OGD and should rapidly receive sensorial rehabilitation.