Clinical and immunological characteristics of antiphospholipid syndrome in an Asian population: a retrospective study.

Objectives: To describe the characteristics of patients with antiphospholipid syndrome (APS) in an Asian clinical practice setting.

Methods: We conducted a single-center, retrospective study of APS patients attending the rheumatology or hematology clinics, between January 2012 and December 2016.

Results: There were 450 patients suspected of having APS referred to our clinics. Seventy-four (16.4%) were diagnosed of APS, 51% of which were definite. Fifty-two (70%) patients were classified as primary APS, 50% of which were definite APS. The most common clinical manifestation was stroke (33%), followed by deep vein thrombosis of the lower extremities (30%) and pulmonary embolism (19%). Hypertension and the presence of at least one established cardiovascular risk factor were independently associated with stroke. Seven (9%) patients had multiorgan thrombosis as their first presentation of APS, 71% of which ultimately suffered from permanent organ damage or died of severe thrombosis, despite not fulfilling the criteria for 'definite' catastrophic APS (CAPS). Late fetal loss was the most prevalent obstetric complication. The majority of patients (79%) tested positive for lupus anticoagulant (LAC), while only 32% tested positive for anti-cardiolipin antibodies. Triple positive profile was documented in 14% of the cohort. Overall, recurrent thrombosis and bleeding complications were recorded in 9% and 28%, respectively.

Conclusion: APS patients in central Thailand demonstrated high prevalence of stroke, late fetal loss, LAC positivity, and multiorgan thrombosis at first presentation, leading to poor outcomes.