Stroke is the most common cause of disability and the third most common cause of death in the United States. We see 700,000 new cases every year, at a cost of more than $43 billion. More than 4 million stroke survivors are unaware they have a high risk for recurrence. The best hope for reducing the number and mortality of strokes is aggressive management of risks and symptoms.
Gender, race affect risk, incidence
The differences in stroke incidence between women and men are somewhat paradoxical. Men are at far higher risk of stroke than women. And risk for both genders increases dramatically with age. Because men generally don’t live as long, however, we treat more women for stroke than men.
We also see significant differences in the incidence of stroke among whites and blacks. Younger blacks suffer strokes far more frequently than their white counterparts, regardless of gender. At older ages, however, we see a surprising drop in the proportion of stroke among black men. For example, at ages 75-84, the incidence of stroke among black men is just 8 per 1,000, compared to 12 in 1,000 for white men, white women and black women. The difference is much more dramatic at age 85+, with more than 30 in 1,000 white men experiencing stroke vs. about 20 in 1,000 for women of both races and less than 15 in 1,000 black men.
Aspirin more helpful to women
We also see a large difference in the effects of daily aspirin on reducing the risk of primary stroke in men and women. For women over 55, daily aspirin slightly reduces the risk of ischemic stroke, but it has no effect on the risk for myocardial infarction. For men 45 and older, the effect is opposite: daily aspirin reduces the risk of MI but not stroke. The effect of aspirin therapy for both issues is slight but considered worth the relative cost. The U.S. Preventive Services task Force recommends both groups take daily low-dose aspirin (81 mg.). After a stroke, the relative risk reduction of daily aspirin is, even for both genders, about 20%.
Prevention efforts generally more successful for women
Hypertension increases a person's risk of stroke by 5-10 times that of the normal population, making its treatment the most effective preventive measure for stroke. Yet estimates suggest we identify and treat only about 25% of all Americans with hypertension. In this area, men don't do nearly as well as women, but the difference is due more to behavior than the efficacy of preventive measures. Men are more resistant to medical care in general, so they don’t get their blood pressure checked as often. Even if they do, they are less likely to comply with medications for risks such as hypertension. Another issue is the general bias of the primary care community toward treatment for hyperlipidemia over treatment for hypertension.
Treatment efficacy also differs
Following a stroke, antiplatelet medications work equally well for both men and women. Surgical treatment, however, presents several differences. For patients who have had a stroke, carotid endarterectomy does reduce the risk of recurrence. For male patients with carotid artery blockage of 50-69%, the risk reduction is dramatic. Women benefit far less.
For asymptomatic patients with carotid stenosis, the efficacy of carotid endarterectomy is much lower than many assume. Several studies have shown the benefit of the surgery is very low – preventing stroke in less than 1 patient in 50 – even for surgeons whose records show very low rates of stroke and death. In fact, when this procedure is performed by a typical surgeon, it carries a 5-9% risk of stroke or death. Therefore, patients with asymptomatic carotid stenosis are more likely to be harmed by surgery than helped. For this reason, I generally advise asymptomatic patients not to pursue carotid ultrasound imaging.
Where we're missing the boat
The most predictive risks for stroke are hypertension and smoking. We can do much better at modifying both.
- Hypertension is undertreated in the U.S. – especially among men. When they do seek medical attention, men are far more likely to be treated aggressively for hyperlipidemia than hypertension. Physicians tend to think they are managing the risk of both stroke and MI by prescribing statins. We must take hypertension more seriously to significantly affect the incidence of stroke.
- Getting patients to stop smoking also is a great challenge – and physicians should be much more aggressive about it. Our hospital has a dedicated stop smoking team that works with stroke patients who are still smoking.
Physicians also can decrease the mortality and morbidity of stroke by taking a more emergent approach to symptoms that may point to transient ischemic attack. When primary care physicians see a patient who exhibits clear stroke symptoms and deficits, they naturally send them to the emergency room. When they see – or hear by phone – of symptoms such as one-sided weakness, numbness or difficulty speaking that have resolved, they are less likely to recommend emergency care. From my perspective, they should be treating these symptoms as urgently as they would treat unstable angina.
In summary, community physicians have many resources available for preventing primary and secondary stroke. Understanding gender differences can be helpful. But the most effective change we can make is to get much more aggressive in treating hypertension among men.
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