Systematic analysis of COVID-19 infection and symptoms in a systemic lupus erythematosus population: correlation with disease characteristics, hydroxychloroquine use and immunosuppressive treatments

We read with interest the article of Bozzalla Cassione et al about COVID-19 incidence in their systemic lupus erythematosus (SLE) cohort. 1 Their study adds useful epidemiological information about COVID-19 risk in SLE. 1 They suggest that hydroxycholoroquine was not protective, but could not draw definite conclusion and open the question to immunosuppressive drugs' influence. We would like to share analysis of our SLE cohort (n=225) that can help to answer these questions and determine COVID-19 infection risk factors. Determining COVID-19 incidence is challenging: PCR lacks sensitivity, was usually realised only in severely ill patients and patients with suggestive benign symptoms could stay at home without medical contact. We studied the incidence of COVID-19 infection, either asserted or suspected, by analysing positive nasopharyngeal PCR, hospitalisation or contact with emergency department, but also suspected diagnosis in ambulatory medicine. Each patient was called by phone to determine COVID-19 suggestive symptoms since 4 February 2020, date of the first case in our country. Among our patients, 92.9% were female, with a mean (±SD) age of 51.7 (±14.9) years. Most recent biological evaluation showed positivity for ds-DNA in 24% (median (min-max) levels: 139 (12-758) IU/mL). Mean (±SD) number of 1997 American College of Rheumatology (ACR), 2019 American College of Rheumatology/European League Against Rheumatism (ACR/ EULAR) and Systemic Lupus International Collaborating Clinics (SLICC) classification criteria were 4.5 (±1.5), 20.0 (±8.1) and 5.8 (±2.2), respectively. One hundred and fifty-two (68.1%) patients received chronic treatment with hydroxychloroquine,