Prevalence of the Antiphospholipid Syndrome and Its Effect on Survival in 679 Chinese Patients With Systemic Lupus Erythematosus: A Cohort Study

In this work we evaluate the prevalence of the antiphospholipid syndrome (APS) and its impact on survival in Chinese patients with systemic lupus erythematosus (SLE). We studied a prospective cohort of southern Chinese patients who fulfilled ≥4 American College of Rheumatology criteria for SLE. The cumulative rate of survival over time was calculated by the Kaplan-Meier method. APS was defined by the 2006 updated consensus criteria. We evaluated the prevalence and manifestations of APS, and compared the survival of patients with and without APS. We followed 679 patients with SLE (92% women; age of onset, 32.5 ± 14 yr) for 9.7 ± 7.3 years. Sixty-eight (10%) patients died and 33 (4.9%) patients were lost to follow-up. Forty-four (6.5%) patients met the criteria for APS, manifested by the following: ischemic stroke (55%), deep venous thrombosis (32%), obstetric morbidity (14%), cardiovascular events (9%), and peripheral vascular disease (9%). Nine (9/44 [20%]) APS patients died, which was more frequent than the non-APS patients (59/635 [9%]; p = 0.02). The cumulative mortality of patients with APS was 4.6% at 5 years, 7.8% at 10 years, and 22.2% at 15 years, which was not significantly higher than that of non-APS patients (5.4% at 5 years, 9.2% at 10 years, and 11.3% at 15 years; p = 0.14). However, if we considered only patients with APS caused by arterial thrombosis, the presence of APS was significantly associated with mortality (hazard ratio, 2.29; 95% confidence interval, 1.13–4.64; p = 0.02). We conclude that the presence of APS increases the mortality risk of Chinese patients with SLE, which is mainly contributed by arterial thrombotic events. Clinical significance: 1) APS is infrequent in southern Chinese patients with SLE compared to white patients. 2) Arterial thrombosis is a more common manifestation of APS than venous thrombosis in Chinese SLE patients. 3) APS related to arterial thrombosis is associated with increased mortality in Chinese patients with SLE.