Anosmia and dysgeusia amongst COVID-19 patients are associated with low levels of serum glucagon-like peptide 1.

ABSTRACT

PURPOSE: Anosmia and dysgeusia (AD) are common amongst COVID-19 patients. These symptoms are not frequently associated with rhinorrhea or nasal congestion and the underlying mechanism is unclear. Previous reports suggested that glucagon-like peptide-1 (GLP-1) signalling plays a role in the modulation of olfaction and ageusia. We aimed to assess the correlation between GLP-1 and COVID-19-associated AD. METHODS: Blood samples obtained from COVID-19 patients with and without AD were tested for serum GLP-1 levels using enzyme-linked immunosorbent assay (ELISA). A second control group comprised of COVID-19-negative volunteers. RESULTS: Forty-nine subjects were included in the study. Nineteen were positive for COVID-19. Of the 19 patients, 10 had AD and 9 declined such complaints. Age and basic metabolic rate were similar amongst all study groups. Serum GLP-1 levels were significantly lower amongst patients with AD compared with patients without AD and COVID-19-negative individuals (1820 pg/mL vs 3536 pg/mL vs 3014 pg/mL, respectively, P < .02). CONCLUSION: COVID-19 patients who reported AD had lower serum levels of GLP-1 compared with those lacking AD symptoms and COVID-19-negative individuals. These results suggest that GLP-1 may be involved in the pathogenesis of AD. However, further larger scale studies should corroborate our findings.