Chulalongkorn Medical Journal


Background : The European League Against Rheumatism (EULAR) recommendsprimary prophylaxis with aspirin and hydroxychloroquine in systemic lupuserythematosus (SLE) patients with antiphospholipid antibodies withoutprior thrombosis. However, Asian populations may have lower incidenceof thrombosis and the role of primary prophylaxis is unclear. Therefore, weexamined the prevalence of thrombosis in Thai antiphospholipid-positiveSLE patients.Methods : The medical records of SLE patients (N = 715) admitted toKing Chulalongkorn Memorial Hospital from 2002 - 2012 were studied. Twohundred and eighteen patients were investigated for antiphospholipidantibodies, and 82 of them (37.6%) were positive. These 82 patients werestudied for baseline characteristics, the types of antiphospholipid antibodies,prevalence of thrombosis and other potential risk factors.Results : The mean age of antiphospholipid - positive patients was 31 years, and80.5% of them were female. The mean duration of SLE was 7.7 years, andthe median follow up time was 3 years. The positive rates for lupusanticoagulant, low-titer anticardiolipin, high-titer anticardiolipin andanti-β2 glycoprotein I were 61% (50/68), 40% (33/73), 23% (19/73) and17% (1/6), respectively. Without aspirin prophylaxis, 23 (28%)antiphospholipid-positive cases developed vascular thrombosis (24.4%)and/or obstetric complications (6.1%). Venous thrombosis was morecommon than arterial sites. The thrombotic rate of medium to high titer andlow titer of anticardiolipin was 36.8% and 21.2%, respectively (p = 0.22).On the other hand, 2.2% (3/136) antiphospholipid-negative patientsdeveloped thrombosis or pregnancy complication with the odds ratio (OR)of 17.28 (95% confidence interval [95%CI] 5.0 - 59.8, p < 0.0001). Uponmultivariate analysis in antiphospholipid-positive SLE, the age of SLEdiagnosis of over 30 years and hydroxychloroquine use showed oddsratios of 2.94 (95% CI 1.02 - 8.43, p = 0.045) and 0.28 (95% CI0.08 - 0.96,p = 0.043), respectively.Conclusion : This study reveals that antiphospholipid antibodies are strong riskfactors for thrombosis in patients with SLE in Thailand. Additionally,hydroxychloroquine may prevent thrombosis in these patients.


Faculty of Medicine, Chulalongkorn University

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