Recovery of Olfactory and Gustatory Dysfunctions in COVID-19 Patients in Iran: A Prospective Cohort Study (preprint)

ABSTRACT

Background: Olfactory and gustatory dysfunctions (OD and GD) manifested unpredictably in COVID-19 patients. Considering the high prevalence of OD and GD and the importance of the sense of smell and taste in the quality of life, this study aimed to determine the association of some demographic and clinical factors with OD and GD recovery in COVID-19 patients in Iran.Methods: This prospective cohort study was performed on COVID-19 patients with OD and GD during the first and second peak of pandemic in Golestan province, Iran. We used a local health care registry system for data collection. All cases had positive RT-PCR test for SARS-CoV-19 in nose and nasopharynx swab samples. Variables included age, sex, ethnicity, geographical location, time of onset of symptoms, severity of OD and GD (complete or partial). The follow-up time for recovery from OD and GD was six months. Time to recovery for OD and GD was estimated by Kaplan-Meier considering complete recovery as an endpoint. Differences among groups were evaluated using log-rank test and Cox proportional-hazard models as appropriate in SPSS version 16.Results: A total of 242 patients completed the study. The mean age of patients was 39.12±11.89 years. There were 127 (52%) females. After six months, 239 (98.8%) patients had complete OD recovery and 80.9% and 83.56% of patients recovered within the first 30 days following the onset of OD or GD, respectively. The mean time of OD recovery was significantly higher (35.07±4.25 days) in cases infected in the first peak of pandemic than in the second peak (21.65±2.05 days) (p=0.004). This finding also was observed for the recovery time of GD (p=0.005). The mean recovery time of GD was significantly higher in women than men (35.55±4.33 vs. 23.20±2.46 days) (p=0.04). The age (less than 20 years), second peak of epidemic, and partial dysfunction were identified as significant predictors for recovery.Conclusions: COVID-19–related OD and GD had high rate of recovery in the first month from onset of symptoms. Age of patients, severity of OD/GD and infecting in second peak of epidemic might be related to the recovery of OD or GD in patients with COVID-19.