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We read with great interest the article by Ye et al,1 which reported the clinical features of COVID-19 in patients with rheumatic diseases, most notably that respiratory failure developed more commonly in patients with rheumatic disease infected with COVID-19 than those without rheumatic disease (38% vs 10%, p<0.001). The authors collected data from a total of 2326 patients with COVID-19 from 13 January to 15 March 2020, including 21 cases in combination with rheumatic disease, and conducted a retrospective case series study of their laboratory indices. However, some conclusions and findings in the study need to be further clarified.
First, the sample size of patients with rheumatic disease infected with COVID-19 was only 21—too small to extrapolate results with statistical confidence. Rheumatic diseases often affect the lungs, which can cause further damage to the respiratory system during flares and this has been reported to lead to respiratory failure.2 The COVID-19 infection can also result in lung disease progression,3 often culminating in respiratory failure. Therefore, when assessing whether patients with rheumatic diseases and COVID-19 are more prone to respiratory failure, it is necessary to first determine whether any of the study patients had a history of lung disease, for example, interstitial lung disease.
Second, the different drugs used to treat rheumatic diseases—including glucocorticoids, antimalarial drugs, non-steroidal anti-inflammatory drugs and disease-modifying antirheumatic drugs (DMARDs)—have different effects on the condition of patients with rheumatic disease infected with COVID-19. Previous studies have suggested that long-term use of glucocorticoids may increase the risk of both serious and opportunistic infections.4 Sharmeen et al5 reported that various DMARDs or biological agents may affect the disease course differently. Notably, taking hydroxychloroquine, tumour necrosis factor antagonists or tocilizumab may result in the patient presenting with a mild viral illness, whereas rituximab or secukinumab could possibly worsen the disease. Meanwhile, Borba et al6 reported that the use of high doses of hydroxychloroquine may present potential safety issues, which is not conducive to the treatment of COVID-19 infection. In Ye’s study, patients with rheumatic diseases include: rheumatoid arthritis, systemic lupus erythematosus, primary Sjögren’s syndrome and so on. The types and dosages of drugs taken by these patients are different, and the effects on diseases after COVID-19 infection are also different. This indicates that the discrepancy in the drugs used by patients with rheumatic disease may also lead to different presentation of respiratory failure.
Lastly, figure 3 in Ye’s study showed several laboratory indices, but not all 21 patients with rheumatic disease infected with COVID-19 had results for every test. This should be noted and the estimated value and interpretation of the data percentage should be adjusted accordingly. Missing data due to current circumstances are understanding as patients may present an emergency condition which prevents indices from being obtained in time, or clinicians may not see the need for certain tests due to patients’ presentation.
For the above-mentioned reasons, it might be too early to draw conclusions regarding the features of COVID-19 in patients with rheumatic diseases. We recommend that future studies increase the sample size of patients with rheumatic disease, and take into account both the patients’ disease activity level and the pharmacological treatments used. This will allow a thorough assessment of the clinical features of patients with rheumatic disease infected with COVID-19.
Contributors All authors contributed equally to the presented work.
Funding This work was supported by funding from the National Natural Science Foundation of China Grants (81760298).
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.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; internally peer reviewed.