Ab0582 description of asymptomatic anti-phospholipid carriers in a french multicenter cohort study

Background Anti-phospholipid antibodies (APL) are associated with thrombotic events or pregnancy complications leading to the so-called anti-phospholipid syndrome (APS) according to the classification criteria last updated in Sydney in 2006. APL can be found in asymptomatic patients. Objectives We observed the clinical, biological characteristics and association with other diseases of asymptomatic APL carriers group, and we compared them with an APS patients group. Methods In this French multicentric retrospective cohort study we analyzed the data of 507 patients with persistent positive APL measured between 2012 and 2019. Clinical and laboratory data were collected retrospectively. Data are expressed as numbers with frequencies and medians with interquartile ranges (IQR). Qualitative and quantitative variables were compared using Fisher and Kruskal-Wallis tests. Cumulative incidence curves of relapse event were generated using Kaplan-Meier. We used Cox model to obtain Hazard Ratio (HR). Proportional hazard assumption was checked using Schoenfeld residuals. Two-sided testing was used, with p ≤0.05 considered statistically significant. Results We observed a majority of female patients of a younger age in the APS group when compared to the APL carriers group. Cardiovascular risk factors were similar in both groups. Systemic lupus erythematosus was more frequently associated with the APS group, but interestingly rheumatoid arthritis, ankylosing spondylarthritis and chronic kidney disease were more frequently associated with asymptomatic APL carriers. At biological level, anti-cardiolipin IgG and beta-2-glycoprotein 1 IgG positivity rates were higher in APS group than in APL carriers group, but not for lupus anticoagulant positivity. Triple-positive APL were more frequent in APS group as expected, but we found up to 13.9% of triple-positive APL in APL carriers group. We also observed a higher prevalence of ANA, anti-dsDNA, anti-SSA/SSB in the APS group. At prognostic level patients from APL carriers group had a lower mortality (2.9 % vs 9.1%, p=0.006) but the observation period for this group was slightly shorter. No thrombotic event was observed in this group during the follow-up period, while 38.8% of APS patients had a relapse (thrombotic or obstetrical event during follow-up). In our subgroup analysis comparing primary and secondary APL carriers, we observed less women than men, an older age and a higher prevalence of cancer in primary APL carriers group. Interestingly, we observed a higher rate of atypical APL in primary APL carriers subgroup, with a trend toward a significant intergroup difference (31.1% vs 21.2%, p=0.075). There was no difference in mortality among groups. Conclusion APL carriers group was associated with the presence of autoimmune disease, infection and cancer. We did not observe any thrombotic events in the APL carriers group during the evaluation period. APS group had a higher mortality as expected. Interestingly, we observed a higher rate of atypical APL in primary APL carriers subgroup, with a trend toward a significant intergroup difference (31.1% vs 20.2%, p=0.075). We did not find a difference in mortality between primary and secondary APL carriers subgroups. References [1]Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). Journal of Thrombosis and Haemostasis 2006;4(2):295–306. [2]Kaul M, Erkan D, Sammaritano L, Lockshin MD. Assessment of the 2006 revised antiphospholipid syndrome classification criteria. Ann Rheum Dis 2007;66(7):927–30. [3]Bertin D, Camoin-Jau L, Veit V, et al. Single or triple positivity for antiphospholipid antibodies in “carriers” or symptomatic patients: Untangling the knot. J Thromb Haemost 2021;19(12):3018–30. Figure 1. Cumulative incidence of thrombotic events over 5 years in APS patients group and asymptomatic APL carriers group. Acknowledgements: NIL. Disclosure of Interests None Declared.