Tongue features of patients with coronavirus disease 2019: A retrospective cross-sectional study

Abstract Background Traditional Chinese medicine (TCM) has been widely used for the treatment of coronavirus disease 2019 (COVID-19). Tongue features are the bases of diagnosis and treatment in TCM. Therefore, it is necessary to analyze the tongue features of patients suffered from COVID-19. Methods COVID-19 Symptom Database (established by Evidence-based Medicine Centre of Tianjin University of TCM) was searched for eligible tongue pictures. The tongue pictures were assessed by TCM expert to extract data of tongue color, coating color, tongue body shape, and coating proper features. Results Patients with mild and moderate COVID-19 commonly had light red tongue and white coating. Severe patients had purple tongue and yellow coating. The proportion of critical patients with tender tongue increased to 75%. The proportions of patients with mild and severe COVID-19 who had greasy coating were 53.33% and 87.5% respectively. The tongue color and coating color of young patient ( 45 years old) with red or purple tongue and yellow coating has increased. There was no significant difference between patients with different gender in tongue features. Conclusions Tongue features may be diagnosis indicators of the type and severity of COVID-19. Studies on tongue features quantification and interference factor of COVID-19 tongue features should be conducted to improve the diagnosis, treatment, and evaluation of COVID-19.