Hydroxychloroquine Use is Associated with Lower Odds of Persistently Positive Antiphospholipid Antibodies And/or Lupus Anticoagulant in Systemic Lupus Erythematosus

Objective: Antiphospholipid antibodies (aPL) play an active role in the pathogenesis of the antiphospholipid syndrome (APS). Primary prevention in APS may be aimed at decreasing existing elevated aPL levels, or preventing high aPL titers and/or lupus anticoagulant (LAC) from developing in the first place. Hydroxychloroquine (HCQ) has been shown in retrospective studies to decrease aPL titers in laboratory studies, and to decrease thrombosis risk in patients with systemic lupus erythematosus (SLE). We investigated an association between HCQ use and persistent aPL and/or LAC in SLE.

Methods: We identified all patients over 21 years old with SLE from an urban tertiary care center who had aPL and LAC measured on at least 2 occasions at least 12 weeks apart. We defined the presence of persistent LAC+ and/or at least 1 aPL ≥ 40 U [immunoglobulin A (IgA), IgG, or IgM] as the main outcome variable.

Results: Among 90 patients included in the study, 17 (19%) had persistent LAC+ and/or at least 1 aPL ≥ 40 U. HCQ use was associated with significantly lower odds of having persistent LAC+ and/or aPL ≥ 40 U (OR 0.21, 95% CI 0.05, 0.79, p = 0.02), adjusted for age, ethnicity, and sex.

Conclusion: This is the first study to show that HCQ use is associated with lower odds of having persistently positive LAC and/or aPL. Data from this study provide a basis for the design of future prospective studies investigating the role of HCQ in primary and secondary prevention of APS.