Date: Sunday, November 8, 2020
Session Type: Poster Session C
Session Time: 9:00AM-11:00AM
Antiphospholipid syndrome (APS) is classified as the development of venous and/or arterial thromboses, and pregnancy morbidity, in the presence of antiphospholipid antibodies (aPL); lupus anticoagulant, moderate-to-high titer anticardiolipin (aCL) and anti-β2- glycoprotein I. LAC positivity is more strongly associated with both arterial and venous thrombosis than either aCL or anti-β2glycoprotein I antibodies in SLE (1).Some studies found that thromboembolic events were significantly higher in “triple positive” patients. The rate of pregnancy loss was also higher in “double positive” patients (2). In contrast, PROMISSE found only LAC to predict adverse pregnancy outcomes. We investigated the risk of thrombosis in Systemic Lupus Erythematosus patients with single LAC positivity versus double and triple positivity in the Hopkins Lupus Cohort.
Methods: Anticardiolipin and anti-Beta2 glycoprotein I were defined as positive when the antibody titer exceeded 20 units.The lupus anticoagulant was determined by dilute Russell’s viper venom time (dRVVT) and confirmatory mixing studies, if prolonged. It was defined as positive if a patient had a dRVVT of 45 or more seconds and a positive confirm ratio of more than 1.4. For each aPL, we defined the patient as positive at a given month of follow up if they ever had a positive value in the previous measures. Logistic regression analysis was used to identify the independent predictive antiphospholipid antibody patterns for risk of lifetime occurrence of any/venous/arterial thrombosis. The odds ratios were adjusted for age. Thrombosis was defined as: arterial thrombosis (C VA, MI, other arterial thrombosis or digital gangrene); and venous thrombosis (D V T, PE or other venous thrombosis)
Results: There were 805 patients with a complete profile of 7 antiphospholipid antibodies, with a total of 73417 person months (6118 person years) of follow up. For any thrombosis when compared to patients with LAC positivity only, double positivity with any isotypes [1.15(0.50, 2.66) p=0.7484] and triple positivity with any isotypes [1.68(0.74, 3.80), p=0.2145] showed higher point estimates but not statistically significant.
Conclusion: Triple or double positive aPL profiles are not superior to single LAC positivity in their association with any thrombosis in SLE patients.
To cite this abstract in AMA style:Demir S, Li J, Magder L, Petri M. Single LAC Positivity versus Double and Triple Positivity for Thrombosis in SLE [abstract]. Arthritis Rheumatol. 2020; 72 (suppl 10). https://acrabstracts.org/abstract/single-lac-positivity-versus-double-and-triple-positivity-for-thrombosis-in-sle/. Accessed September 27, 2021.
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