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What Is the Prevalence of Olfactory Dysfunction in COVID-19 Patients?

by Linda Kossoff •

What is the overall pooled prevalence of olfactory dysfunction in COVID-19 patients?

BOTTOM LINE

Evidence indicates that the prevalence of olfactory dysfunction in COVID-19 patients is 48.85%; further studies are advocated to confirm the finding.

BACKGROUND: The Centers for Disease Control and Prevention includes olfactory dysfunction in its list of presenting symptoms for COVID-19. However, the symptom’s prevalence in COVID-19 patients varies widely, and a previous meta-analysis may have been too limited to yield a representative figure of its global prevalence among COVID-19 patients.

STUDY DESIGN: Systematic review and meta-analyses.

SETTING: Department of Otorhinolaryngology–Head and Neck Surgery, School of Medical Sciences, Kubang Kerian, Malaysia.

SYNOPSIS: Researchers conducted a database search using key terms related to COVID-19 and olfactory dysfunction. They identified 83 studies that met the criteria for their systematic review and meta-analysis. Collectively, the studies represented data from 27,492 COVID-19 patients (38.6% male, 61.4% female) in 27 countries throughout four continents. Overall, the pooled prevalence of olfactory dysfunction in COVID-19 patients was 47.85%. A subgroup analysis found olfactory dysfunction in 54.4% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID-19 patients. Based on clinical severity, olfactory dysfunction was higher in non-severe patients compared to severe patients (47.48% vs. 9.02%). As in previous reviews, female predominance in olfactory loss was revealed. In addition, the prevalence of olfactory dysfunction among objectively evaluated studies was higher (72.10%) as compared to subjectively evaluated studies (44.53%). Authors suggested that development of a new, research-based questionnaire would serve as an effective and easily assimilated screening tool for olfactory dysfunction. Study limitations included the possibility that prevalence findings might not represent on a global scale and that the analyzed studies used self-reported data.

Citation: Saniasiaya J, Islam MA, Abdullah B. Prevalence of olfactory dysfunction in coronavirus disease 2019 (COVID-19): A meta-analysis of 27,492 patients. Laryngoscope. 2021;131:865-878.