Persistence of antiphospholipid antibodies over time and its association with recurrence of clinical manifestations: A longitudinal study from a single centre.

PURPOSE: To analyze the antiphospholipid antibody (aPL) persistence over time in patients with antiphospholipid syndrome (APS) and its association with clinical recurrence and to identify predictors of aPL persistence over time. PATIENTS AND METHODS: 200 patients with a diagnosis of APS and at least three follow-up aPL determinations were included. Persistent aPL profile was defined as the presence of lupus anticoagulant (LAC) and/or IgG/IgM anticardiolipin (aCL) and/or IgG/IgM anti-ß2 glycoprotein-I (aß2GPI) (> 99th percentile) antibodies in at least 66% of follow-up measurements. Multilevel mixed-effect generalized linear models with logit link were used. RESULTS: 112 (56%) patients maintained persistent aPL profiles over time, while 88 (44%) were transient. Median follow-up time was 172.5 months. Follow-up time did not affect the odds of aPL persistence in multivariate analysis (p = 1.00). Baseline triple aPL positivity [OR 78 (95%CI 16.9-359.7, p < 0.001)] and double aPL positivity [OR = 7.6 (95%CI 3.7-15.7, p < 0.001)] correlated with persistent aPLs over time, while isolated LAC [OR = 0.26 (95% CI 0.08-0.49, p = 0.002)] or isolated IgG/IgM aCL [OR = 0.20 (95% CI 0.11-0.59, p = 0.004)] positivity, were predictors of transient aPL profile. Patients with persistent aPLs had higher rate of clinical recurrence in comparison to patients with transient aPLs [OR = 2.48 (95%CI 1.34-4.58, p = 0.003)]. CONCLUSIONS: More than half of patients with baseline medium-high titer aPL positivity had persistent positive aPLs over time. Patients with persistent aPLs were more prone to present recurrence of clinical manifestations. Multiple aPL positivity increased the odds of a persistent aPL profile over time, while isolated LAC and aCL positivity decreased it.