Predictive Value of Olfactory and Taste Symptoms in the Diagnosis of COVID-19: A Systematic Review and Meta-Analysis

Abstract

Objectives: This study evaluated the diagnostic value of the various symptoms of COVID-19 in the screening of this disease.Methods: Two authors (working independently) comprehensively reviewed six databases (PubMed, Cochrane database, Embase, Web of Science, SCOPUS, and Google Scholar) from their dates of inception until November 2020. Patient-reported symptoms, including otolaryngologic and general symptoms, were evaluated for their predictive values in adults who underwent testing for COVID-19. True-positive, true-negative, false-positive, and false-negative data were extracted from each study. The methodological quality of included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies tool (ver. 2). Results: Twenty-eight prospective and retrospective studies were included in the meta-analysis. The diagnostic odds ratio (DOR) of a change in olfaction and/or taste was 10.20 (95% confidence interval [CI], 8.43; 12.34). The area under the summary receiver operating characteristic curve was 0.8. Olfactory and/or taste changes had a low sensitivity (0.57, 95%CI: 0.47; 0.66) but moderate negative (0.78, 95%CI: 0.69; 0.85] and positive (0.78, 95%CI: 0.66; 0.87) predictive values and a high specificity (0.91, (95%CI: 0.83; 0.96). Olfactory and/or taste changes had a higher diagnostic value than the other otolaryngologic symptoms, a higher DOR and specificity, and a similar or higher diagnostic value than the other general symptoms. Conclusions: Among otolaryngologic symptoms, olfactory and/or taste dysfunction was the most highly associated with COVID-19 and its general symptoms and should be considered when screening for the disease.

Self-Reported Olfactory Dysfunction and Diet Quality: Findings from the 2011–2014 National Health and Nutrition Examination Survey (NHANES)

“…Loss of sense of smell is a hallmark sign of COVID-19 [1][2][3][4][5], emerging early in the disease course and affecting most infected individuals. For most COVID-19 patients, smell-related symptoms tend to resolve within a few weeks; however, 10-20% of individuals may experience chronic smell alterations, persisting beyond six months after onset [89][90][91][92][93].…”

“…The coronavirus-19 (COVID-19) pandemic has brought important attention to the chemical senses and the role that poor diet and related conditions, such as obesity, play in the risk of COVID-19 infection. Loss of sense of smell, taste and/or possibly chemesthesis 2 of 18 is a hallmark sign of COVID-19 [1][2][3][4][5], emerging early in the disease's course and affecting most infected individuals. Self-reported olfactory dysfunction (OD) is an important indicator of a smell problem and is one of the best predictors of a positive COVID-19 status [5][6][7].…”

Exploring the Clinical Utility of Gustatory Dysfunction (GD) as a Triage Symptom Prior to Reverse Transcription Polymerase Chain Reaction (RT-PCR) in the Diagnosis of COVID-19: A Meta-Analysis and Systematic Review

“…Comparing the clinical utility of GD (with or without OD) to OD (with or without GD) by Pang et al [49], either GD, OD, or both by Kim et al [155] in predicting COVID-19 RT-PCR positivity, it can be seen that GD has the lowest DOR and sensitivity, while equivalent specificity. The data in Table 1 suggests that the combination of either GD, OD, or both, may be the best screening criteria, among the 3, to predict COVID-19 RT-PCR positivity.…”

Clinical Presentation of the SARS-CoV-2 Virus Infection and Predictive Validity of the PCR Test in Primary Health Care Worker Patients of the Spanish National Health System

“…A study carried out in healthcare professionals in the Netherlands showed that general non-respiratory symptoms (muscle pain, eye pain, general malaise, headache, extreme tiredness and fever) were reported more frequently by healthcare personnel with a positive diagnostic test, and these symptoms were strongly associated with the positivity of the SARS-CoV-2 test in contrast to respiratory symptoms such as coughing and sneezing [ 8 ]. Since the clinical manifestations of patients with COVID-19 are often nonspecific especially in the initial phase [ 9 ], and resemble other similar diseases such as influenza, the clinical diagnosis of COVID-19 is really complicated [ 10 ]. For this reason, several studies have investigated possible predictive models of symptoms associated with SARS CoV-2 virus infection, obtaining heterogeneous results in the different international series [ 11 , 12 , 13 ].…”

“…Despite the impact that SARS CoV-2 virus infection has presented in Spain, data on the diagnostic capacity of the symptoms associated with this infection are limited [ 10 , 14 ], especially among patients with mild and that are detected in the primary care field (PC), despite the fact that they represent more than 80% of the reported cases [ 14 ].…”