Differences in the clinical profile between isolated lupus anticoagulant and triplepositive antiphospholipid antibody profiles in primary antiphospholipid syndrome.

OBJECTIVE

To compare the clinical phenotype of patients with primary antiphospholipid syndrome who have isolated lupus anticoagulant positivity versus those with triple positivity.

METHODS

This cross-sectional study included two cohorts from two tertiary centers in Brazil comprising patients diagnosed with primary antiphospholipid syndrome.

RESULTS

Of 313 patients, 135 were selected and divided into two groups. A total of 99 had isolated lupus anticoagulant positivity and 36 had triple positivity. Most participants were female (58.5%) and White (61.5%), with a mean age of 50.1±12.0 years and a median disease duration of 16 (12-22) years. Both groups showed similar rates of thrombosis (93.9% in the lupus anticoagulant group versus 100% in the triple positivity group, p=0.131) and obstetric events (55.8% versus 60.0%, p=0.754). Microthrombotic and non-thrombotic event rates were also comparable. Hydroxychloroquine use was higher in the triple-positive group (36.1%) than in the lupus anticoagulant group (15.2%, p=0.008).

CONCLUSION

No more severe phenotype was observed in patients with triple positivity compared with those with isolated lupus anticoagulant positivity. The mixed ancestry and demographic composition of the Brazilian population may explain differences compared with more homogeneous populations.