Clinical Significance of Smell and Taste Dysfunction and Other Related Factors in COVID-19

Abstract

Purpose The objective of this study is to evaluate smell and taste dysfunction (STD) in coronavirus disease 2019 (COVID-19) positive and negative patients, and to assess the factors associated with STD in COVID-19 positive patients. Methods Patients who had been tested with the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for COVID-19 were identified, and according to the RT-PCR test results, patients were separated into Positive and Negative Groups. A telephone-based assessment was applied to both groups using the American Academy of Otolaryngology-Head and Neck Surgery Anosmia Reporting Tool. Patients in Positive Group were also asked to rate STD, nasal breathing, and anxiety in three different time periods (pre-/during-/post-COVID) using the visual analog scale (VAS). Results A total of 53 COVID-19 positive and 51 negative patients completed the surveys. STD was eightfold more frequent (OR 8.19; CI 95% 3.22-20.84) in the Positive Group. Of the 53 COVID-19 positive patients, 32 reported STD and 21 did not. 'Ground-glass appearance' on chest-computed tomography was more frequent and median lymphocyte count was significantly lower in COVID-19 positive patients with STD. During-COVID STD and nasal breathing VAS scores were significantly lower than the pre- and post-COVID scores. During-COVID STD scores were significantly correlated with anxiety scores (Spearman's rho-0.404, p = 0.022) but not correlated with nasal breathing scores. Conclusion STD may be related to increased inflammatory response as well as damage of olfactory neuronal pathway or non-neuronal olfactory mucosa. Understanding the exact cause of chemosensory impairment in COVID-19 can be helpful in explaining the pathophysiology of the disease.