Subjective smell and taste dysfunctions and prognosis in patients with COVID-19 admitted to a major public hospital in Southern Brazil: A retrospective cohort study (NUTRICOVID19)

The literature notes that coronavirus disease 2019 (COVID-19) patients with olfactory disturbances tend to have lower disease severity and that olfactory disturbances may act as a protective factor against mortality. So, this study aimed to explore the association of smell and/or taste disturbance with disease severity and all-cause mortality among patients who were hospitalized with COVID-19. A retrospective cohort study (Nutrition and COVID-19 Study [NUTRICOVID19]) was conducted with 1331 patients (men and women, age ≥ 18 years) hospitalized with COVID-19 between June and December 2020. Poisson and Cox regressions were used to investigate the unadjusted and adjusted associations between smell and/or taste disturbance and the following prognostic indicators: length of stay (LOS), intensive care unit admission, need for invasive mechanical ventilation (IMV), and mortality. Patients with altered smell and/or taste had a shorter LOS (9 vs 11 days), were less likely to require IMV (22% vs 35.1%), and experienced lower mortality (17.1% vs 29.2%) compared to those without such symptoms. After multivariable adjustment, patients with smell and/or taste disturbances were 33% less likely to need IMV compared to those without such symptoms (RR = 0.67; 95% CI = 0.50-0.88), but the relationship between these symptoms and mortality lost statistical significance. In this population of patients with COVID-19, the presence of smell and/or taste disturbances was associated to lower rates of IMV.