AB0433 Disease Characteristics, Survival Analysis and Mortality in A Single Centre Cohort of 240 Patients with Antiphospholipid Syndrome

Background Antiphospholipid syndrome (APS) is an autoimmune disease characterized mainly by thrombosis and/or pregnancy morbidity in the presence of antiphospholipid (aPL) antibodies. Significant mortality and morbidity has been reported in patients with APS. Objectives To characterize a single center cohort of patients with APS (including non-criteria manifestations) and to assess their survival rates, causes of mortality and associations with disease characteristics. Methods Records of 240 patients with APS were studied. Demographic characteristics, cumulative clinical and laboratory features, autoantibody profiles were retrieved from the existing database. Unattending patients were contacted by telephone and were searched on the national death information system (NDIS). Patients who were non-responsive to telephone calls, not seen in the outpatient clinic within the last 6 months and could not be traced on the NDIS were considered lost-to follow-up. Results There is a total of 240 patients in this cohort 118 of whom had primary APS and 122 had APS associated with SLE. 83% of the patients were female. The mean age at diagnosis was 41±12, duration of disease and follow-up were 110±85 and 92±82 months respectively. Of 240 patients, 65% had vascular thrombosis (VT), 24% had pregnancy morbidity (PM), 10% had both VT and PM and 3 had catastrophic antiphospholipid syndrome. Overall 29% patients had thrombotic risk factors among which smoking followed by homozygous factor V Leiden mutation were the most prevalent. Of patients with VT 49% had arterial (a), 38% had venous (v) and 13% had both a and v thrombosis. 95 patients experienced a single thrombotic episode whilst 62 had more than once, most commonly v followed by a thrombosis. In the PM group, there were 31 patients with fetal deaths beyond 10 weeks, 39 with 3 or more abortions before 10 weeks, 18 with premature labour and 14 with pre-eclampsia. Overall, 46% of patients had aCL IgG, 36% had IgM and LA was present in 54%. Anti-β2GPI was tested in 117 patients and 38% were positive for IgG and 25% for IgM. Of the non-criteria manifestations of APS, the most common presentation was heart valve lesions followed by thrombocytopenia. In total there were 25 deaths and 19 patients were lost to follow-up. Survival rates were 94, 86, 78 and 71% at 5, 10, 15 and 20 years respectively. Comparison of survival between patients with VT and PM displayed a marked reduction in the VT group (p=0.04) whilst primary and lupus associated APS patients had similar rates. Causes of death could be identified in 19 patients. Myocardial infarction, alveolar hemorrhage and pulmonary hypertension were the leading causes of death. Mortality was significantly associated with LA positivity (p=0.02). Conclusions In this cohort, the most prevalent manifestation of APS was arterial thrombosis. Long-term follow up revealed that patients with APS had significant mortality and APS-related manifestations dominated the causes. Thrombotic patients had a reduced survival relative to PM patients. No single aPL test was sufficiently sensitive in the evaluation of APS. LA positivity was a risk factor for reduced survival. Disclosure of Interest None declared