Prevalence and Reversibility of Smell Dysfunction Measured Psychophysically in a Cohort of COVID-19 patients

Link to article at PubMed

Int Forum Allergy Rhinol. 2020 Aug 6. doi: 10.1002/alr.22680. Online ahead of print.


BACKGROUND: Considerable evidence suggests that smell dysfunction is common in Coronavirus Disease 2019 (COVID-19). Unfortunately, extant data on prevalence and reversibility over time are highly variable, coming mainly from self-report surveys prone to multiple biases. Thus, validated psychophysical olfactory testing is sorely needed to establish such parameters.

METHODS: One hundred SARS-CoV-2 positive cases were administered the 40-item University of Pennsylvania Smell Identification Test (UPSIT) in the hospital near the end of the acute phase of the disease. Eighty-two were retested 1 or 4 weeks later at home. The data were analyzed using analysis of variance and mixed-effect regression models.

RESULTS: Initial UPSIT scores were indicative of severe microsmia, with 96% exhibiting measurable dysfunction; 18% were anosmic. The scores improved upon retest [initial and retest means (95%CIs) = 21.97 (20.84,23.09) & 31.13 (30.16,32.10; p<0.0001)]; no patient remained anosmic. After five weeks from COVID-19 symptom onset, the test scores of 63% of the retested patients were normal. However, the mean UPSIT score at that time continued to remain below that of age- and sex-matched healthy controls (p<0.001). Such scores were related to time since symptom onset, sex, and age.

CONCLUSION: Smell loss was extremely common in the acute phase of a cohort of 100 COVID-19 patients when objectively measured. About one-third of cases continued to exhibit dysfunction after five post-symptom onset weeks. These findings have direct implications for the use of olfactory testing in identifying SARS-CoV-2 virus carriers and for counseling such patients in regards to their smell dysfunction and its reversibility. This article is protected by copyright. All rights reserved.

PMID:32761796 | DOI:10.1002/alr.22680

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