Incidence and risk factors for moderate/severe COVID-19 in rheumatic diseases patients on hydroxychloroquine: a 24-week prospective cohort

Objective To evaluate the incidence of COVID-19 and its main outcomes in rheumatic disease (RD) patients on hydroxychloroquine (HCQ) compared to household cohabitants (HC).Methods This is a 24-week nationwide prospective multi-centre cohort with a control group without RD and not using HCQ. All participants were monitored through scheduled phone interviews performed by health professionals. Details regarding COVID-19 symptoms, and epidemiological, clinical, and demographic data were recorded on a specific web-based platform. COVID-19 was defined according to the Brazilian Ministry of Health criteria and classified as mild, moderate or severe.Results A total of 9,585 participants, 5,164 (53.9%) RD patients on HCQ and 4,421 (46.1%) HC were enrolled from March 29th, 2020 to September 30th, 2020, according to the eligibility criteria. COVID-19 confirmed cases were higher in RD patients than in cohabitants [728 (14.1%) vs. 427 (9.7%), p<0.001] in a 24-week follow-up. However, there was no significant difference regarding outcomes related to moderate/ severe COVID-19 (7.1% and 7.3%, respectively, p=0.896). After multiple adjustments, risk factors associated with hospitalisation were age over 65 (HR=4.5; 95%CI 1.35-15.04, p=0.014) and cardiopathy (HR=2.57; 95%CI 1.12-5.91, p=0.026). The final survival analysis demonstrated the probability of dying in 180 days after a COVID-19 diagnosis was significantly higher in patients over 65 years (HR=20.8; 95%CI 4.5-96.1) and with 2 or more comorbidities (HR=10.8; 95%CI 1.1-107.9 and HR=24.8; 95%CI 2.5-249.3, p=0.006, respectively).Conclusion Although RD patients have had a higher COVID-19 incidence than individuals from the same epidemiological background, the COVID-19 severity was related to traditional risk factors, particularly multiple comorbidities and age, and not to underlying RD and HCQ.