The effects of comorbidities on the change of taste and smell in COVID‐19 patients

BACKGROUND: Sudden chemosensory changes were considered an early predictor of COVID‐19. Here, the effects of comorbidities on changes in taste and smell in COVID‐19 patients were investigated based on a worldwide study. METHODS: Data analyzed here were collected from the Global Consortium for Chemosensory Research (GCCR) core questionnaire, including questions regarding preexisting disease conditions. Overall, the final sample of 12,438 participants who were diagnosed with COVID‐19 included patients with preexisting conditions. Mixed linear regression models were used to test our hypothesis, and the p‐value of interaction was examined. RESULTS: A total of 61,067 participants completed the GCCR questionnaire, including 16,016 participants had preexisting diseases. The multivariate regression analysis showed that individuals with high blood pressure, lung disease, or sinus problems, or neurological diseases exhibited worse self‐reported smell loss (p < .05), but no apparent significant differences in the smell or taste recovery. COVID‐19 patients with seasonal allergy/hay fever lost their olfactory ability more than patients who did not have it (with 11.90 [9.67, 14.13] vs. without 6.97 [6.04, 7.91], p < .0001). The taste ability, smell loss and taste loss after COVID‐19 recovery also decreased in the COVID‐19 patients with seasonal allergy/hay fever (p < .001). Preexisting condition of diabetes did not worsen to chemosensory disorder but also had no obvious impact on the chemosensory recovery after acute infection. Preexisting diseases also affected the type of smell change in the COVID‐19 patients with seasonal allergy/hay fever or sinus problems (p < .05). CONCLUSIONS: COVID‐19 patients with high blood pressure, lung disease, or sinus problems, or neurological diseases exhibited worse self‐reported smell loss, but no differences in the smell or taste recovery. COVID‐19 patients with seasonal allergy/hay fever had greater loss of smell and taste, poorer smell and taste recovery. LEVEL OF EVIDENCE: 4