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We read with interest the recent report by Mathian et al1 about 17 patients with systemic lupus erythematosus (SLE) and COVID-19, which has paved the way to a constellation of articles aiming to find clues on potential peculiarities in COVID-19 epidemiology and course among patients with SLE. An ongoing debate has also recently grown on the role of hydroxychloroquine (HCQ), with increasing data disconfirming a protective effect of this drug towards severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in general and specifically also in patients with SLE.2 3 We were thus prompted to summarise the evidence published so far on this latter topic to look for recurrent clinical or epidemiological patterns among different studies/cohorts. To this aim, we analysed all studies published in the English literature until June, 30th 2020 and identified 20 articles describing a total of 4059 patients with SLE, 255 of whom with a PCR-confirmed or presumptive (ie, based on symptoms or radiological findings) diagnosis of COVID-19 (table 1).
The occurrence of COVID-19 cases among patients with SLE was investigated within disease-specific2–7 (n=6) or general rheumatology (n=5)8–12 cohorts, total (n=2)13 14 or patients with only SLE hospitalised for COVID-19 (n=2),1 15 infected patients with rheumatic diseases (n=3),16–18 multinational registries (n=1)19 or population statistics (n=1).20 Based on previous estimates about the local prevalence of SLE and on actual data from two studies,13 20 we found that only four to six studies2 9–11 13 14 included in their analysis at least 5% of the expected SLE population within their region/area. Considering those studies where a cohort denominator was available, 41 (0.9%)/4307 patients with SLE had a PCR-confirmed diagnosis of COVID-19, only slightly exceeding the expected prevalence of COVID-19 in the general population. In addition, 72 (3.7%)/1953 patients had symptoms consistent with COVID-19 without PCR confirmation. Establishing a presumptive diagnosis of COVID-19 in patients with SLE is challenging, since multiple symptoms (such as fever, myalgia or dyspnoea) might be part of the clinical spectrum of SLE. Recently, we and others2 3 10 described the prevalence of symptoms potentially related to COVID-19 within a whole lupus cohort. Data from these works suggest that patients with SLE might frequently develop one or more symptoms among rhinorrhoea, myalgia (both 19% frequency), cough (18%), sore throat (17%), fever (11%) and less frequently (but potentially more specifically) diarrhoea (10%), conjunctivitis (9%), dyspnoea (8%), anosmia or ageusia (5%) and chest pain (5%). Association analyses between HCQ use and COVID-19 were available from six studies,2 3 5 14 17 19 three of which2 3 5 with data from patients with SLE who did not develop COVID-19: 101 (69%)/147 patients with SLE and COVID-19 were taking HCQ, compared with 526 (71%)/736 patients with SLE without COVID-19, suggesting that antimalarials may not per se be sufficient to prevent COVID-19 in patients with SLE. Little is still known about COVID-19 severity in patients with SLE. Cohort-based studies reproducibly show that COVID-19 prevalence in SLE is probably similar to that of the general population, possibly with marked dependence on containment measures such as home confinement.2 8 Although these studies are strengthened by the large number of screened patients, they can underrepresent patients with severe COVID-19, who might not be contactable at time of interview. Conversely, case series of hospitalised or infected patients as well as disease registries might be limited by reporting biases (preferential reporting of severe cases), small sample sizes and absence of appropriate control groups, but still highlight the potential association between comorbid SLE and difficult or even fatal COVID-19 course.1 12 19
We are grateful to the B.I.R.D. Foundation Europe, Costozza di Longare (VI), Italy for its support to the School of Allergy and Immunology of the Università Vita-Salute San Raffaele, Milan, Italy.
Contributors GAR designed the study, collected and analysed the data and drafted the manuscript. All authors contributed to the design of the study and to revise it critically for important intellectual content. All authors contributed in revising the manuscript and approved its final version.
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.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; internally peer reviewed.
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