key: cord-0794735-6tg5pr4a authors: Romero‐Gameros, Carlos Alfonso; Waizel‐Haiat, Salomón; Mendoza‐Zubieta, Victoria; Anaya‐Dyck, Alfredo; López‐Moreno, Mayra Alejandra; Colin‐Martinez, Tania; Martínez‐Ordaz, José Luis; Ferat‐Osorio, Eduardo; Vivar‐Acevedo, Eulalio; Vargas‐Ortega, Guadalupe; Wacher Rodarte, Niels H.; González‐Virla, Baldomero title: Evaluation of predictive value of olfactory dysfunction, as a screening tool for COVID‐19 date: 2020-10-22 journal: Laryngoscope Investig Otolaryngol DOI: 10.1002/lio2.482 sha: 4b20494e5659c33672ba06eb82c2cf6eaa8d7566 doc_id: 794735 cord_uid: 6tg5pr4a OBJECTIVES: At the end of 2019, SARS‐CoV‐2 was identified, the one responsible for the COVID‐19 disease. Between a 5.1% and a 98% of COVID‐19 patients present some form of alteration in their sense of smell. The objective of this study is to determine the diagnostic yield of the smell dysfunction as screening tool for COVID‐19. METHODS: Cross‐sectional, observational, and pro‐elective study was performed in a tertiary care hospital from May 25th to June 30th, 2020. One hundred and thirty‐nine patients were included in the study. Demographic characteristics were collected from anamnesis. A Self‐Perception Questionnaire and psychophysical olfactory test (POT) were applied to all participants. The presence of SARS‐CoV2, was detected by RT‐PCR methods. RESULTS: 51.7% of patients were SARS‐CoV‐2 positive. A sensitivity of 50% was obtained for the self‐perception questionnaire as a screening tool for SARS‐CoV2, with a specificity of 80.59%. The positive predictive value (PPV) was of 73.46%, the negative predictive value (NPV) was of 60%. The POT as a screening tool had a PPV of 82.35%, a NPV of 52.45%, a LR+ of 4.34, a LR‐ 0.84. The combination of anosmia (according to the POT) plus cough and asthenia got an OR of 8.25 for the SARS CoV‐2 infection. CONCLUSION: There is a strong association between olfactory dysfunction and COVID‐19. However, it is not really efficient in the screening of SARS‐CoV‐2 infection and thus, they should not be considered as a single diagnostic instrument. LEVEL OF EVIDENCE: 4. Conclusion: There is a strong association between olfactory dysfunction and COVID- 19 . However, it is not really efficient in the screening of SARS-CoV-2 infection and thus, they should not be considered as a single diagnostic instrument. Level of Evidence: 4. In the mild to moderate cases, it is characterized by fever, dry cough, headache, asthenia, and odynophagia. 1 Generally speaking, the information reported so far suggests that between a 5.1% 8 and a 98% 5 of COVID-19 patients present some form of alteration in their sense of smell or taste; which seems to be a common symptom in the early stages of the diseases, 9 noticeable even before a diagnosis in between 53.1% and 73%, 3, 10, 11 ; as a first symptom in between 8.7% 12 and 26.6% 3, 6, 13, 14 ; and it has occasionally been reported as the only symptom in 5.1%. 10, 15 Recently, Haehner et al published their results of a cross-sectional study in which a 98.7% specificity and a 22.7% sensitivity were reported in the self-assessment questionnaire of smell alterations, as a screening method. 16 For all of the above mentioned reasons, some authors 6, 16, 17 propose using a smell assessment as a quick, accessible and low-cost method for detecting COVID-19 patients. The objective of the hereby study is to determine the diagnostic yield of the questionnaire and the psychophysical olfactory test as screening instruments for COVID-19. A cross-sectional, observational and pro-elective study was performed at the Specialties Hospital Centro Médico Nacional Siglo XXI, part of the Mexican Institute of Social Security in Mexico City, Mexico. The study covered a period of time from May 25th to June 30th, 2020; and it included patients who sought a respiratory TRIAGE assessment, due to COVID-19 suspicion. The study was carried out in an office next to the respiratory TRIAGE area (medical emergency area for patients with clinical suspicion of COVID-19), after the emergency medicine doctor's assessment. A team of three otolaryngology residents volunteered to collect the demographic data and medical background; and they also applied the self-perception questionnaire and the psychophysical olfactory test (POT). It was the same team all throughout the study ( Figure 1 ). The patients had to meet the following inclusion criteria in order to be able to participate: older than 18-years-old (of legal age), a nasopharyngeal swab test had to be taken to test for SARS-CoV-2, and the patients ought to present a mild to moderate form of the disease, for an ambulatory treatment. They also had to sign their agreement to voluntarily participate in the study. The exclusion criteria applied did not consider patients older than 65-years-old, those with a Parkinson or Alzheimer history, chronic rhinosinusitis, allergic rhinitis; those who did not have a SARS-CoV-2 RT-PCR result; or patients who required hospitalization. All the patients signed an informed consent form; and the hereby study was approved by the Research and Ethics Committee of the hospital (CI 09015034/CEI 0232017082/R 2020 3601 124). The following information was requested during the interview: age, sex, schooling, surgical background, comorbidities, general symptoms and ENT symptoms (rhinorrhea, dysosmia, nasal obstruction, odynophagia, and dysgeusia). Fever was defined as body temperature greater than 38 C (100.4 F). The data was entered into an electronic database for further analysis. The questionnaire enclosed in Appendix A was used. It required the patient to indicate if at the time of the assessment they had suffered loss of smell (yes vs no), to quantify the loss of smell in a visual analog scale (where 0 was no loss of smell and 10 was a total loss of smell). They were also required to state when the loss started (1. A stratified analysis was done with the intention of constructing a diagnostic instrument. It included anosmia (detected by the questionnaire and/or the PST), cough and asthenia. Those signs and symptoms were associated to the SARS-CoV-2 positive test. For the data analysis, descriptive and inferential statistics were applied, considering the central and dispersion trend measures. Hypertension was present in 9.72%, followed by asthma (5.56%) and type 2 diabetes (2.78%). A 13.89% of the patients reported rhinoplasty/septoplasty. No significant differences were observed in the medical history (Table 1 ). Headache was reported by 58.33% of the patients, followed by asthe- Through the Kappa test a concordance between Self-perception questionnaire of smell disorders and the PST of 73.38% was observed, for the detection of smell dysfunction, kappa: 0.40, P = .000. Table 5 . This study was carried out with the purpose of assessing the performance of the PST and self-perception of olfactory impairment as a diagnostic instrument for detecting SARS-CoV-2. The strength of our study is that it is pro-elective nature in the data collection, the application of a psychophysical olfactory test, a reasonable sample size, and the bio-statistical complexity of the study analysis. The weaknesses of the study include: first the sample size. Second the use of a Pocket Smell test of a 3-item instead of de full version of 40 items and third, the limitation of RT-PCR for the detection of SARS-CoV2, in nasopharyngeal swab samples, which has a suboptimal sensitivity (as low as 60%), 26 which leads to a high number of false negatives. Both tests, the self-perception questionnaire of smell disorders and the PST, are useful tools in the detection of SARS-CoV2 infection, especially in the presence of concomitant symptoms such as cough and asthenia. Even though there is evidence of a strong association between olfactory alterations (reported by the patient and even by psychophysical olfactory tests) and COVID-19, they are not really efficient in the screening test of SARS-CoV-2 infection due to the low sensitivity and thus, they should not be considered as a single diagnostic instrument. This study proposes the combination of diagnostic instruments (symptomatology scale) to lead to a better screening in the clinical practice of the SARS-CoV-2 infection. More studies are needed to assess the diagnostic instruments, and with a larger number of patients. The present study was carried out with resources from the Mexican Institute of Social Security. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). 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