One-Seventh of Patients with COVID-19 Had Olfactory and Gustatory Abnormalities as Their Initial Symptoms: A Systematic Review and Meta-Analysis

Abstract

Coronavirus disease 2019 (COVID-19) patients exhibited protean clinical manifestations. Olfactory and gustatory abnormalities (anosmia and ageusia) were observed in COVID-19 patients, but the reported prevalence varied. In this systematic review, the prevalence of olfactory and gustatory abnormalities (OGA) was evaluated in laboratory-confirmed COVID-19 patients. On 8 May 2020, 14,506 articles were screened, while 12 of them were enrolled. A total of 1739 COVID-19 patients were analyzed, with a wide range of prevalence observed (5.6–94%). The pooled prevalence was 48.5% with high heterogeneity (I2, 98.8%; p < 0.0001). In total, 15.5% had OGA as their first symptom (I2, 22.6%; p = 0.27) among the patients analyzed. Contradictory to COVID-19 negative controls, patients with COVID-19 had a higher risk of OGA (odds ratio, 5.3; I2, 66.5%; p = 0.03). In conclusion, approximately half of COVID-19 patients had OGA, and one-seventh of them had OGA as their initial symptoms. OGA were cardinal symptoms of COVID-19, which may serve as clues for early diagnosis. Diagnostic testing for SARS-CoV-2 was suggested in patients with OGA during the COVID-19 pandemic to ensure timely diagnosis and appropriate quarantine.

Clinical Characteristics, Diagnosis, and Treatment of Major Coronavirus Outbreaks

“…A meta-analysis of 27 studies showed a pooled prevalence of loss of smell and taste in these patients to be 41.47% (95% Cl 3.13-31.03%) and 35.04% (95% Cl 22.03-49.26%), respectively (133). Both of these symptoms presented in patients on average on the fourth day after initial symptoms of the disease, but 13-15.5% of patients had a loss of smell and taste sensation as the first symptom (134,135).…”

Sudden anosmia and ageusia in a child: A COVID-19 case report

“…The prevalence of olfactory and gustatory dysfunction may be close to half of patients with COVID-19 [ 10 ]. Early studies have recognized olfactory dysfunction as the primary or isolated presenting symptom in 17%–26% of cases [ 10 , [16] , [17] , [18] ]. A recent meta-analysis demonstrated one-seventh of its patients presented with olfactory and gustatory abnormalities as their initial symptoms [ 17 ].…”

Taste alteration in COVID-19: a rapid review with data synthesis reveals significant geographical differences

“…The first study reporting a 5.1 and 5.6% prevalence of hyposmia and hypogeusia, respectively, was a pre-print (non-peer-reviewed) case series of a Chinese population (Mao et al, 2020). In sharp contrast, a most recent meta-analysis analyzing smell and taste alterations not only reported that almost half of COVID-19 patients had these symptoms but, also, that 15% of patients had olfactory and gustatory abnormalities as their initial symptoms (Chi et al, 2020).…”