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Correspondence to ‘Prevalence of hospital PCR-confirmed COVID-19 cases in patients with chronic inflammatory and autoimmune rheumatic diseases’
  1. Bo-Yao Wu1,2,
  2. Chi-Ho Chan3,4,
  3. James Cheng-Chung Wei5,6,7
  1. 1 Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
  2. 2 School of Medicine, Chung Shan Medical University, Taichung, Taiwan
  3. 3 Department of Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan
  4. 4 Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan
  5. 5 Department of Allergy, Immunology & Rheumatology, Chung Shan Medical University Hospital, Taichung, Taiwan
  6. 6 Institute of Medicine, College of Medicine, Chung Shan Medical University, Taichung, Taiwan
  7. 7 Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan
  1. Correspondence to Dr James Cheng-Chung Wei; jccwei{at}

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We read with great interest the article by Pablos et al.1 However, we consider some methods and findings in the study that need to be further clarified.

First, detection bias may exist in this study because patients with AI/IMD visit hospitals for medical examinations regularly. Therefore, patients under follow-up in rheumatology department exactly showed higher prevalence of hospital PCR+COVID-19 than the reference population.

Second, to the best of our knowledge, Sjögren’s syndrome is a slow-developing syndrome.2 However, we can find out that in this study, patients with Sjögren’s syndrome showed remarkably higher rates of COVID-19 than those in the other AI/IMD groups, despite the fact that Sjögren’s syndrome is mild than others. Therefore, we suggest that the authors need to explain this result in the discussion.

Third, in general, more serious cases of autoimmune diseases, that is, systemic lupus erythematosus (SLE), will have tendency to become more susceptible to COVID-19. However, it is not the case in this research article. The authors explained the reason was due to frequent use of antimalarial drugs, that is, chloroquine/hydroxychloroquine in patients with SLE. However, despite the side effects of chloroquine/hydroxychloroquine, it has been proved to have no therapeutic effect in patients with COVID-19.3 So, the explanation may not be true in SLE. In addition, spectrum of autoantibodies in different autoimmune diseases may co-relate with the susceptibility for COVID-19.

If the reasons mentioned in the correspondence could be clarified and discussed further, the study will become a great pioneer to identify the risk factors of COVID-19 in the future and to combat the new and threatening virus.

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  • B-YW and C-HC contributed equally.

  • Contributors BYW and CHC conceived and wrote the manuscript. JCCW reviewed and commented on the manuscript. All authors approved the final version of the manuscript. The first two authors contributed equally to the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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