Clinical characteristics and risk factors of microvascular involvement in primary antiphospholipid syndrome: a longitudinal single-center study in China

Abstract

Objectives The objective of this study was to investigate risk factors of microvascular involvement and survival in Chinese patients with primary antiphospholipid syndrome. Methods In this single-center, retrospective study, we enrolled 112 patients with a confirmed diagnosis of primary antiphospholipid syndrome who were admitted to Peking Union Medical College Hospital from January 2004 to December 2016. Demographic data, clinical characteristics, laboratory results, and follow-up records were collected. Results A total of 112 patients with primary antiphospholipid syndrome were studied. Microvascular involvement was identified in 21 patients (18.75%). Patients with microvascular involvement experienced fewer episodes of arterial or venous thrombosis (28.6% vs. 84.6%) and a higher incidence of thrombocytopenia (85.7% vs. 54.9%), respectively. Low complement and elevated high-sensitivity CRP levels were observed more frequently in the microvascular group compared with the non-microvascular group (complement 38.1% vs. 18.7%; high-sensitivity CRP 71.4% vs. 31.9%, respectively). Anti-β2-glycoprotein I antibodies were more prevalent in patients with microvascular involvement than in patients without (66.7% vs. 33.0%, respectively). Multivariate logistic regression analysis revealed that thrombocytopenia (odds ratio = 4.523, 95% confidence interval 1.139–17.962), elevated high-sensitivity CRP levels (odds ratio = 6.385, 95% confidence interval 1.969–20.704), and anti-β2-glycoprotein I antibody positivity (odds ratio = 5.042, 95% confidence interval 1.555–16.352) were independent risk factors for microvascular involvement. A Kaplan–Meier analysis revealed that survival was significantly poorer in patients with microvascular involvement compared with patients without ( p = 0.0278). Conclusions In addition to arterial and venous thrombosis, antiphospholipid syndrome can affect the microvasculature of select organs. It is thus important for clinicians to be aware that antiphospholipid syndrome-associated microvascular involvement has a unique pathogenesis and can be a life-threatening condition.