Does hydroxychloroquine prevent symptomatic venous thromboembolism in patients with mild to moderate COVID-19?

ABSTRACT

Background: SARS-CoV-2 infection can trigger an important immune reaction, induce antiphospholipid antibodies, and is associated with a high-risk of venous thromboembolism (VTE), especially in patients with severe or critical disease. Hydroxychloroquine is an immunomodulator that had proven some efficacy in preventing thrombosis in antiphospholipid syndrome. Aims: To investigate if hydroxychloroquine prevents symptomatic VTE in patients with mild to moderate COVID-19. Methods: Ancillary study of HYCOVID trial, a prospective, multicenter, randomized, double-blind trial aiming to assess the efficacy of hydroxychloroquine with regard to the 14-day rate of death or invasive ventilation ( https//clini caltr ials.gov/ct2/show/NCT04 325893 ). COVID-19 patients were included, with their informed consent, if they had at least one of the following risk factors for worsening need for supplemental oxygen, age ≥75 years, age between 60 -74 years and presence of at least one comorbidity. Eligible patients were randomized to receive either 800 mg hydroxychloroquine on Day 0 followed by 400 mg per day for 8 days, or a placebo. In the present study, we assessed the 28-day cumulative rate of symptomatic VTE. All suspected events were adjudicated by an independent committee, blinded to treatment allocation. Results: Two hundred and fifty patients were enrolled;124 and 123 patients received hydroxychloroquine or placebo and were included in the modified intention-to-treat analysis, respectively. Eightyseven percent of the patients received an anticoagulant treatment during hospitalization (104 [83.9%] and 111 [91.2%] in the hydroxychloroquine and the placebo group, respectively) (Table). Two patients in each group experienced VTE within the 28 days following inclusion. All events were pulmonary embolism (PE), including one fatal PE in the placebo group. The VTE rate was 1.61% (95%CI 0.20 to 5.70) in the hydroxychloroquine group and 1.63% (95% confidence interval 0.20 to 5.75) in the placebo group ( P = 1.00). Conclusions: In patients hospitalized for mild to moderate COVID-19, the rate of symptomatic VTE was low with no evidence of benefit of hydroxychloroquine.