Tongue Coating in COVID-19 Patients: A Case-Control Study

  1. Zhi Chun Wang
  2. Xi Hong Cai
  3. Jeremy Chan
  4. Yi Yi Chan
  5. Xiaotong Chen
  6. Ching Wan Cheng
  7. Donghui Huang
  8. Bei-ni Lao
  9. Xu-sheng Liu
  10. Aiping Lu
  11. Huixian Wang
  12. Helen Zhang
  13. Xuebin Zhang
  14. Shi Ping Zhang

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

It has been suggested that COVID-19 patients have distinct tongue features, which may help to monitor the development of their condition. To determine if there was any specific tongue coating feature in COVID-19, this study investigated the difference in tongue coating between COVID-19 subjects and subjects with other acute inflammatory diseases characterized by fever. Tongue images taken with smartphones from three age-matched groups, namely, COVID group (n=92), non-COVID febrile group (n=92), and normal control group (n=92), were analyzed by two blinded raters according to a tongue coating scoring scheme, which assessed the levels of thick fur, slimy or greasy fur, discolored fur and composite index of tongue coating. Compared with control, significant increases in all coating indexes were found in the COVID group (P<0.001), as well as in the non-COVID febrile group (P<0.001). However, no difference was observed between COVID and non-COVID febrile groups for all coating indexes measured. In COVID-19 subjects, their scores of coating indexes had weak but significant correlations with certain inflammatory biomarkers, including WBC and neutrophil - lymphocyte ratio. It is concluded that COVID-19 subjects have pathological tongue coating patterns that are associated with inflammatory responses, and these coating patterns can help to indicate the direction of disease development.

Article activity feed

  1. Version published to 10.1101/2022.03.14.22272342v2 on medRxiv
  2. ScreenIT

    SciScore for 10.1101/2022.03.14.22272342: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    EthicsConsent: Informed consent was obtained from healthy participants and non-COVID febrile subjects, but was waived for COVID subjects due to the retrospective nature of the study and the exceptional circumstances.
    Sex as a biological variablenot detected.
    RandomizationThe remaining control subjects (n=41), whose data were retrieved randomly from a tongue image database of our previous studies [12], were from Guangdong and Hong Kong.
    BlindingThe raters consisted of three Chinese medicine practitioners (CYC, YYC, BNL) and three Chinese medicine students (XTC, QYC, JC), who were blinded to the source and diagnosis of the images.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    (Adobe Photoshop CC 2019) to reduce the influence of different light sources.
    Adobe Photoshop
    suggested: (Adobe Photoshop, RRID:SCR_014199)
    Statistical analysis: Data were analyzed with IBM SPSS Statistics (version 26.0) and GraphPad Prism (version 8.0.2).
    SPSS
    suggested: (SPSS, RRID:SCR_002865)
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    There are a number of limitations in this study that are worth noting. For example, the source of COVID-19 patients are all from Wuhan at a particular time period. Thus, it is not known whether new COVID variants could produce specific tongue coating patterns not seen in the current study. Due to the lack of matching subjects, we have to exclude many older age COVID-19 patients, resulting in a relatively small sample size. As well, because the medical records of COVID-19 patients are incomplete, it is not possible to control for any comorbid disease in the study population. Therefore, findings from the current study should be interpreted with the above limitation in mind. In conclusion, COVID-19 patients have pathological tongue coating that is associated with inflammatory responses, and their coating changes may indicate the direction of disease development. Further studies are warranted to explore the application of tongue imaging as an adjunct diagnostic method in monitoring the development of COVID-19.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2022.03.14.22272342v1 on medRxiv