NEW YORK -- September 29, 2009 -- A study published online first and in the November edition of The Lancet Neurology shows that women with a particular subtype of antibody called lupus anticoagulant (LA) have a more than 40-fold increased risk of stroke and 5-fold increased risk of myocardial infarction (MI) compared with the general population. In addition, smoking and oral contraceptive use increase the risk of these events even more.
Although it is known that antiphospholipid syndrome causes thrombosis, bleeding, and repeat miscarriage in women, the extent of the increased risk for stroke and MI was unknown before this study.
Rolf Urbanus, MD, and Philip de Groot, MD, of the University Medical Centre Utrecht, Utrecht, the Netherlands, together with colleagues from the Leiden University Medical Centre, and colleagues used data from the Risk of Arterial Thrombosis In Relation to Oral Contraceptives (RATIO) study for their analysis.
A total of 1,006 women aged under 50 years were enrolled between 1990 and 2001. Questionnaires were used to assess the prevalence of various risk factors, with blood samples taken to measure various phospholipid antibodies, including LA. The patient pool included women who had had a stroke (175) or MI (203), and healthy controls (628).
LA was found in 30 (17%) patients with stroke, 6 (3%) patients with MI, and in 4 (0.7%) healthy controls. Based on the observation that 4 of 628 healthy controls had LA, the prevalence in women in the general population is estimated by the authors to be 7 in 1000, or 0.7%; previous studies have made higher estimates.
LA increased the risk of stroke 43-fold compared with healthy controls; in women with LA who smoked, the risk was raised 87-fold; and in women with LA who used oral contraceptives, the risk was increased more than 200-fold.
LA also increased with risk of MI 5-fold compared with healthy controls; LA plus smoking increased the risk 34-fold, and LA plus oral contraceptives increased the risk 22-fold. Smoking and oral contraceptive use enhance the action of LA, explaining these increased risks.
"Our results suggest that lupus anticoagulant is a major risk factor for arterial thrombotic events in young women, and the presence of other cardiovascular risk factors increases this risk even further…Screening for lupus anticoagulant in young women with ischaemic stroke seems to be warranted," the authors wrote.
SOURCE: The Lancet Neurology
E-Mail this DGNews to a colleague
