The risk of thrombotic events is elevated in patients with systemic lupus erythematosus (SLE) compared to the general population and has been attributed to both systemic inflammation and the presence of antiphospholipid antibodies (aPL). Records of Caucasian and AA patients with SLE and VTE events were retrieved from a Rheumatology practice based at an academic hospital. A clinically significant aPL profile was defined as anti‐cardiolipin IgG/IgM and anti‐β2 glycoprotein‐I IgG/IgM ≥40 units, and positive lupus anticoagulant (LA) ≥1.3.

Ninety‐seven patients fulfilled ACR and 2012 SLICC classification criteria for SLE, had a history of VTE, and available aPL tests (59 Caucasian and 38 AA). African Americans were 66% less likely (95% CI 0.12, 0.96; p=0.04) to have a clinically significant aPL profile compared to Caucasians in multivariable regression. Triple positivity was most frequent among Caucasians, while 7/8 AAs had a positive LA test. At the time of the VTE event, AAs had significantly higher levels of anti‐dsDNA (p=0.02), lower hemoglobin (p=0.01), and higher erythrocyte sedimentation rate (p=0.008).

In conclusion, among patients with SLE and VTE events, AAs were less likely to have a clinically significant aPL profile than Caucasians, indicating that a negative aPL profile in AA does not decrease VTE risk.