Prevalence of Taste and Smell Dysfunction in Coronavirus Disease 2019

Abstract

Importance: Early diagnosis of coronavirus disease 2019 (COVID-19) may help control the diffusion of the disease into the population.

Objective: To investigate the presence of sinonasal manifestations at the onset of COVID-19 to achieve an earlier diagnosis.

Design, setting, and participants: This retrospective telephone survey study investigated patients diagnosed with COVID-19 from March 5 to March 23, 2020, who were hospitalized or discharged from a single referral center. Patients who were unable to answer (intubated, receiving noninvasive ventilation, or deceased) or unreachable by telephone were excluded. Of 359 consecutive patients, 204 fulfilled the inclusion criteria; 76 were unable to answer, 76 were unreachable by telephone, and 3 refused.

Exposures: Sinonasal manifestations reported before COVID-19 diagnosis were studied with a validated questionnaire: Italian Sino-Nasal Outcome Test 22 (I-SNOT-22). If reduction of taste and/or smell was documented by item 5 of the I-SNOT-22, further inquiries were made to score them separately on a scale from 0 to 5, with 0 indicating no problem and 5 indicating problem as bad as it can be.

Main outcomes and measures: The prevalence of sinonasal manifestations preceding COVID-19 diagnosis.

Results: Among the 204 patients enrolled (110 [53.9%] male; mean [SD] age, 52.6 [14.4] years), the median I-SNOT-22 total score was 21 (range, 0-73). I-SNOT-22 identified 116 patients (56.9%) with reduction of taste and/or smell, 113 (55.4%) with taste reduction (median score, 5; range, 2-5), and 85 (41.7%) with smell reduction (median score, 5; range, 1-5). Eighty-two patients (40.2%) reported both. Severe reduction of taste was present in 81 patients (39.7%), and severe reduction of smell was present in 72 patients (35.3%). Only 12 patients (14.8%) with severe taste reduction and 12 patients (16.7%) with severe smell reduction reported severe nasal obstruction. Severe reduction of taste and smell was more prevalent in female vs male patients (odds ratios, 3.16 [95% CI, 1.76-5.67] vs 2.58 [95% CI, 1.43-4.65]) and middle-aged vs younger patients (effect sizes, 0.50 [95% CI, 0.21-0.78] vs 0.85 [95% CI, 0.55-1.15]). No significant association was observed between smoking habits and severe reduction of taste (odds ratio, 0.95; 95% CI, 0.53-1.71) and/or smell (odds ratio, 0.65; 95% CI, 0.35-1.21).

Conclusions and relevance: The findings of this telephone survey study suggest that reduction of taste and/or smell may be a frequent and early symptom of COVID-19. Nasal obstruction was not commonly present at the onset of the disease in this study. The general practitioner may play a pivotal role in identifying potential COVID-19 in patients at an early stage if taste and/or smell alterations manifest and in suggesting quarantine before confirmation or exclusion of the diagnosis.