Recovery rates and parosmia in olfactory loss during the COVID-19 era.
Janne Schwab, Alexander Wieck Fjældstad
Abstract
INTRODUCTION: Olfactory dysfunction (OD) is a common symptom of COVID-19. In some patients, OD persists for many months, fluctuates during recovery or parosmia may occur. Knowledge about the prognosis of these patients is insufficient. METHODS: Data on chemosensory function and possible prognostic factors were collected through a baseline questionnaire and six follow-up questionnaires answered at 2-3-month intervals. RESULTS: One year after onset of OD, 42.0% of the respondents reported sustained complete recovery, 41.7% reported partial recovery and 2.4% reported no improvement of olfaction. Follow-up was unavailable for 13.9%. Parosmia, high severity of OD and female sex were associated with lower rates of recovery. Subjects who reported that OD had a high impact on their quality of life were less likely to recover within one month. Smoking, alcohol habits, BMI and physical activity were not associated with persistence of OD. CONCLUSIONS: High recovery rates were reported within the first months. Recovery of sensory function after more than six months with no prior improvement was reported. After one year, 97.1% of participants with at least one year of follow-up had reported at least some recovery. Recurring OD after initial complete recovery was reported by 24.5% of participants. Parosmia and severity of OD were associated with prolonged recovery rates. FUNDING: AF received research funding from Velux Fonden. The sponsors had no say nor any responsibilities in relation to the study. TRIAL REGISTRATION: not relevant.