Prognosis of patients with coronavirus disease with or without anosmia: A systematic review.

INTRODUCTION

According to numerous research, anosmia has been reported more frequently as one of coronavirus disease (COVID-19) symptoms. However, whether anosmia is a relevant prognostic factor of COVID-19 outcomes is still unknown. A systematic review and meta-analysis were conducted to evaluate the relationship between anosmia and COVID-19 prognosis.

METHODS

PubMed, PubMed Central, Google Scholar and the WHO COVID-19 Research Database were scanned for published literature from September 2021 to December 2022 about the prognosis of patients positive for COVID-19 with anosmia. 'COVID-19' and 'prognosis' were among the search terms used. Pooled estimates of odds ratios (ORs) were then calculated by comparing patients with and without anosmia in terms of intensive care unit (ICU) admission and death.

RESULTS

A total of 16 full-text articles were included in this systematic review. There were a total of 40 deaths among the patients with olfactory dysfunction and 1681 deaths among those without olfactory dysfunction, with an OR of 0.19 (95% confidence interval: 0.10, 0.34; P<0.0001), indicating that the patients with COVID-19 with olfactory dysfunction had a decreased mortality rate.

CONCLUSION

The good prognosis of patients with COVID-19 with anosmia is demonstrated in our study by the low mortality rate in those with anosmia. However, there is no association between the prognosis and ICU admission among patients with COVID-19 with anosmia.