Lupus anticoagulant a major risk factor for stroke/MI in young women

Thrombosis Risk
Lupus anticoagulant a major risk factor for stroke and MI in young women
October 7, 2009 | Susan Jeffrey
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Adapted from Medscape Medical News—a professional news service of WebMD


Utrecht, the Netherlands - A new study shows that lupus anticoagulant, a subtype of antiphospholipid antibodies (aPL), dramatically increases the risk for ischemic stroke and to a lesser degree MI in young women [1].

The presence of lupus anticoagulant was associated with a more than 40-fold increase in the risk for stroke and a fivefold increase in MI. The presence of other cardiovascular risk factors, such as smoking or use of oral contraceptives, dramatically compounded this already-high risk.

Anti-2-glycoprotein I antibodies were associated with an increased risk for stroke but not MI, and no increase in the risk for stroke or MI was seen with anticardiolipin or antiprothrombin antibodies.

"We found in this specific group that only the lupus anticoagulant is an important risk factor for ischemic stroke, and I think that's quite important because it indicates that you have to choose this assay to detect the risk," corresponding author Dr Philip de Groot (University Medical Center Utrecht, the Netherlands) said in an interview.

Their report was published online September 28, 2009 in Lancet Neurology.



Antiphospholipid syndrome


Antiphospholipid syndrome is an acquired risk factor for arterial thrombosis. The syndrome has been found to be more prevalent in women under the age of 50 than the general population, the authors write. It is characterized by vascular thrombosis or complications during pregnancy, followed by a repeated positive test for antiphospholipid antibodies at least 12 weeks apart.

A number of different subpopulations of autoantibodies can be measured, including lupus anticoagulant, anticardiolipin antibodies, anti-2-glycoprotein I antibodies, and antiphospholipid antibodies. "There's always a long debate on two things," de Groot said. "How important are these antibodies for the risk of thrombosis, and which one of these assays is the best?"

To look further at these questions, the researchers used data from the Risk of Arterial Thrombosis in Relation to Oral Contraceptives (RATIO) study, a large, multicenter population-based case-control study looking at risk factors associated with arterial thrombosis, including MI, ischemic stroke, and peripheral vascular disease.

They enrolled women under the age of 50 years who were admitted to the hospital at 16 centers with a first ischemic stroke or MI between January 1990 and October 1995. Another 59 women who presented with an ischemic stroke to their institution between 1996 and 2001 were also included. Information was collected on cardiovascular risk factors, and during the second phase between 1998 and 2002, blood samples were taken to measure antiphospholipid antibody profiles and determine genetic prothrombotic risk factors.

In all, the population included 175 patients with ischemic stroke, 203 with MI, and 628 healthy controls matched for age, residence area, and index year.

Lupus anticoagulant was found in 30 (17%) of those women with ischemic stroke, six (3%) of those with MI, and only four (0.7%) of those in the control group. The presence of lupus anticoagulant was associated with a high risk for both MI and stroke, a risk greatly compounded by use of oral contraceptives or smoking.

Risk for MI and ischemic stroke associated with lupus anticoagulant alone and in combination with oral-contraceptive use and smoking

Event
Odds ratio
95% CI

MI

Lupus anticoagulant alone
5.3
1.4-20.8

+Oral contraceptives
21.6
1.9-242.0

+Smoking
33.7
6.0-189.0

Ischemic stroke

Lupus anticoagulant alone
43.1
12.2-152.0

+Oral contraceptives
201.0
22.1-1828.0

+Smoking
87.0
14.5-523.0


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Among those women who had anti-2-glycoprotein I antibodies, the risk of ischemic stroke was elevated, with an odds ratio of 2.3, but no increase in MI risk was seen. No increase in the risk of either stroke or MI was seen with anticardiolipin or antiprothrombin antibodies.

"This is an observational study, so we do not say anything about the mechanism, but what we see—and we were surprised ourselves—was that the number of patients with antiphospholipid antibodies in this specific group (with stroke) is so high," de Groot said. "I think the most important message is that if you see a young lady with a stroke, measure these antibodies, because there is a fair chance she will have these antibodies and that will influence treatment."

Although the prevalence of lupus anticoagulant in the general population is low, the population-attributable risk of 20.1% "suggests that lupus anticoagulant is responsible for a large proportion of strokes in young women," they write, although they add that the overall incidence of stroke among young women is still low, about 0.3 per 1000 person-years.

Ladies,

This study reinforces our experiences with the combined dangers to younger women on birth control pills + smoking. The risk for HA and/or stroke skyrockets. See stats below.

"Still, they conclude, the new results "add further evidence for lupus anticoagulant and anti-2-glycoprotein I as arterial thrombotic risk factors. Most important, they elucidate that young women with aPL should be informed about the serious risks of cigarette smoking and the use of oral contraceptives."


for secondary prevention after noncardioembolic stroke call for antiplatelet over anticoagulant therapy, but some experts prefer anticoagulants in those with antiphospholipid syndrome, the authors conclude. "Therefore, screening for lupus anticoagulant in young women with ischemic stroke seems to be warranted."





http://www.theheart.org/article/1010925.do