Prevalence and clinical significance of antiphospholipid antibodies among hospitalized COVID-19 patients

Objective: To describe the prevalence of antiphospholipid antibodies in coronavirus disease-19(COVID-19) and to find potential associations between antiphospholipid antibody positivity and clinical outcomes.Methods: From September to November 2020, clinical and laboratory data were collected from 50 COVID-19 patients hospitalized at Saiful Anwar General Hospital in Malang, Indonesia. Antiphospholipid antibodies were measured by finding Ig M anti-β2 glycoprotein, lupus anticoagulant, and Ig M/Ig G anticardiolipin. Clinical characteristics, thrombotic events, ICU admission, and mortality during hospitalization were recorded. Disease severity was defined by the Guidelines for the Prevention and Control of COVID-19, Indonesia.Results: Among 50 patients, 5 patients(10.0%) were positive for antiphospholipid antibodies: 4 patients(80.0%) had Ig M anti-β2 glycoprotein and 1 patient had Ig G anti-cardiolipin(20.0%) and Ig M anti-cardiolipin(20.0%), none of lupus anticoagulant was detected. Antiphospholipid antibodies were associated with anosmia(OR 8.1; 95% CI 1.1-57.9; P=0.018), nausea and vomiting(OR 12.4; 95% CI 1.2-122.6; P=0.010), diarrhea(OR 9.8; 95% CI 1.3-70.9; P=0.010), cardiovascular disease(OR 1.4; 95% CI 1.0-1.9; P=0.001), chronic kidney disease(OR 12.0; 95% CI 1.6-90.1; P=0.05), acute coronary syndrome(OR 29.3; 95% CI 2.0-423.7; P=0.001), moderate(OR 0.11; 95% CI 0.01-1.10; P=0.031) and severe(OR 18.5; 95% CI 1.8-188.4; P=0.002) disease severity, and in-hospital mortality(OR 8.1; 95% CI 1.1-57.9; P=0.018). However, there is no correlation between the presence of antiphospholipid antibody and ICU admission.Conclusions: In summary, the prevalence of antiphospholipid antibodies in COVID-19 patients is low, mainly against Ig M anticardiolipin, and is associated with an acute coronary syndrome, gastrointestinal manifestations, moderate and severe disease severity, and increased risk of mortality.