Potency of Anosmia and Ageusia as Covid-19 Prognostic Factors: A Systematic Review

Abstract

Introduction: The clinical signs of COVID-19 include ageusia and anosmia. Anosmia and ageusia haven’t been evaluated as prognostic factors in any prior studies, though. Therefore, the purpose of this review is to assess the effectiveness of ageusia and anosmia as prognostic indicators in COVID-19 patients. Methods: Literature was collected from various databases systematically using the PRISMA until May 25th,2022. The screening process was performed based on inclusion and exclusion criteria, before being analyzed qualitatively. The risk of bias was assessed using Newcastle-Ottawa Quality Assessment Scale converted by AHRQ. Results: Anosmia and ageusia could be used as the indicator for the good prognostic associated with lower mortality, milder trajectory rate, ICU, and hospital admission risk, and shorter length of stay. Anosmia and ageusia have shown high prevalence to predict a prognosis for the COVID-19 infection. Although COVID-19 prognosis also depends on the other lying conditions, patients with anosmia or ageusia had a lower mortality risk due to the lower body mechanism and cell inflammation mechanism toward the viral load that may not lead to the maladaptive cytokine release in response to infection generally called as a cytokine storm. Conclusion: In COVID-19 patients, anosmia and ageusia have been shown to be indicators of a favorable prognosis due to lower disease severity, mortality, risk of ICU and hospital admission, and shorter duration of stay. Therefore, in order to determine the prognosis, it is important to assess the clinical symptoms of the patients.