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 IgM anti-β2 glycoprotein, lupus anticoagulant, and IgM/IgG 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 IgM anti-β2 glycoprotein and 1 patient had IgG anti-cardiolipin (20.0%) and IgM 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 IgM anticardiolipin, and is associated with an acute coronary syndrome, gastrointestinal manifestations, moderate and severe disease severity, and increased risk of mortality.