Background Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of aPL and at least a clinical event defined as recurrent venous thrombosis, arterial thombosis or pregnancy morbidity. The titers of aPL usually fluctuate, they frequently decrease and eventually become negative during follow-up period, thus reducing the risk of thrombotic events.
Objectives The aim of this study was to explore the clinical and serological course of fertile women with positive aPL, as well as the factors and the potential therapeutic implications associated with aPL negativization.
Methods We conducted a retrospective study including women attending the obstetric autoimmune pathology clinic of a tertiary-facility serving a population in about 350,000 in Northern Spain. We included 105 women with a confirmed positive APL serology according to Sydney Criteria between October 1995 and December 2013. Patients were classified into 3 different groups: A) patients with primary APS (49), B) patients with a positive serology for APL, not meeting clinical criteria (42) and C) patients with systemic lupus erythematosus and a positive serology for APS (14). They were also classified, according to the serological APL evolution: patients with persistently negative aPL, transiently positive serology and persistently positive serology according to previously established criteria.
Results After a mean follow up of 114,4±37,2 months, 59% patients had persistently negative antibodies, while 25,7% patients presented persistently positive aPL serology. After the multivariate analysis only the tobacco use (OR 3,5 p=0,013) was confirmed as an independent risk factor. The load of antibodies, specially the presence of triple positivity (OR: 2,4; IC: 0,16–2,36), was close to statistical significance (p=0,162). No other factors, including traditional cardiovascular risk factors, treatments or clinical manifestations reached statistical significance. Persistent positivity was associated with higher risk for further pregnancy morbidity (41 vs 52%; p=0,328). In 17 patients, with persistently negative serology who were asymptomatic, treatment with low dose aspirin was discontinued. No clinical events related to APS were reported after treatment withdrawal, during a 119,9 months follow-up period.
Conclusions Our study suggests that among fertile women, antiphospholipid antibodies remain persistently positive only in one quarter of patients, being tobacco use an independent risk factors for its persistence. Among patients with persistently negative serology and with a low-risk profile discontinuation of antiplatelet therapy could be considered a safe choice.
Disclosure of Interest None declared