Venous Thromboembolic Events in African American Lupus Patients in Association With Antiphospholipid Antibodies Compared to White Patients.

Objective: 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 to the presence of antiphospholipid antibodies (aPLs). Our objective was to examine differences in aPL prevalence in White and African American patients with SLE and venous thromboembolic (VTE) events, and to compare inflammatory markers at the time of a VTE event.

Methods: Records of White and African American 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/or anti-β -glycoprotein I IgG/IgM ≥40 units, and/or positive lupus anticoagulant ≥1.3. Logistic regression was used to determine predictors of a clinically significant aPL profile.

Results: Ninety-seven patients fulfilled American College of Rheumatology and/or 2012 Systemic Lupus Erythematosus International Collaborating Clinics classification criteria for SLE, had a history of VTE events, and had available aPL tests (59 White and 38 African American patients). African American patients were 66% less likely (95% confidence interval 0.12-0.96; P = 0.04) to have a clinically significant aPL profile compared to White patients in multivariable regression. Triple positivity was most frequent among White patients, while 7 of 8 African American patients had a positive lupus anticoagulant test. At the time of a VTE event, African American patients had significantly higher levels of anti-double-stranded DNA (P = 0.02), lower hemoglobin (P = 0.01), and higher erythrocyte sedimentation rate (P = 0.008).

Conclusion: Among patients with SLE and VTE events, African American patients were less likely to have a clinically significant aPL profile compared to White patients, indicating that a negative aPL profile in African American patients does not decrease VTE risk.