An update on stroke risk and prevention

I have written on stroke several times, due to the constant flow of intriguing and valuable new studies. On the one hand, it is great to have refinement of treatment paradigms. On the other, unfortunately, stroke remains one of the top five causes of mortality and morbidity in the United States.

Recent studies have involved issues from identifying chronic diseases that increase stroke risk (AMD, RA and migraine) to examining the roles of medications and lifestyle in managing risk.

Impact of chronic diseases

There are several new studies that show chronic diseases — such as age-related macular degeneration, rheumatoid arthritis and migraine with aura — increase the risk for stroke. Therefore, patients with these diseases must be monitored.

AMD study

In the ARIC study, stroke risk was approximately 50 percent greater in patients who had AMD, compared to those who did not — 7.6 percent vs. 4.9 percent, respectively (Stroke online April 2012). This increase was seen in both types of stroke: ischemic (complete blockage of blood flow in the brain) and hemorrhagic (bleeding in the brain). The risk was greater for hemorrhagic stroke than for ischemic, 2.64 vs. 1.42 times increased risk. However, there was a smaller overall number of hemorrhagic strokes, which may skew the results.

This was a 13-year observational study involving 591 patients diagnosed with AMD, ages 45 to 64. Most patients had early AMD. If you have AMD, you should be followed closely by both an ophthalmologist and a primary care physician.

Rheumatoid arthritis

In a recent observational study, patients with RA had a 30 percent increased risk of stroke (BMJ 2012; Mar 8;344:e1257), and those under 50 years old with RA had a threefold elevated risk. This study involved 18,247 patients followed for a 13-year period.

There was also a 40 percent increased risk of atrial fibrillation, a type of arrhythmia or irregular heartbeat. Generally, AF causes increased stroke risk, however, the authors were not sure if AF contributed to the increased risk of stroke seen here. They suggested checking regularly for AF in RA patients, and they surmised that inflammation may be an underlying cause for the higher number of stroke events.

Migraine with aura

In the Women’s Health Study, an observational study, the risk of stroke increased by twofold in women who had migraine with aura (Neurology 2008 Aug 12; 71:505). Only about 20 percent of migraines include an aura, and the incidence of stroke in this population is still rather rare, so put this in context (Neurology. 2009;73(8):576).

As I mentioned in my previous article on migraine, there are studies, as well as anecdotal stories showing diet plays a significant role in preventing and decreasing the frequency of migraine.

Medications with beneficial effects

There are two medications recently that have shown positive impacts on reducing stroke risk: statins and valsartan. Statins are used to lower cholesterol and inflammation, and valsartan is used to treat high blood pressure.

Statins have received bad press recently due to their risks of side-effects, such as diabetes, cognitive impairment and myopathy (muscle pain). However, used in the right setting, statins are very effective. In one study, there was reduced mortality from stroke in patients who were on statins at the time of the event (AAN conference: April 2012). Patients who were on a statin to treat high cholesterol had an almost sixfold reduction in mortality compared to those with high cholesterol who were not on therapy.

There was also significant mortality reduction in those on a statin without high cholesterol, but with diabetes or heart disease. The reason for the latter result is not clear, so we should not jump to conclusions, especially since the study is only published in abstract form.

The authors surmise that this result might be from an anti-inflammatory effect of the statins. Of course, if you have side effects, you should contact your physician immediately.

Valsartan is an angiotensin II receptor blocker that works on the kidney to reduce blood pressure. However, in the post-hoc analysis (looking back at a completed trial) of the Kyoto Heart Study data, valsartan used as an add-on to other blood pressure medications showed a significant reduction, 41 percent, in the risk of stroke and other cardiovascular events for patients who have coronary artery disease (Am J Cardiol 2012; 109(9):1308-1314).

It is important to recognize that chronic disease increases stroke risk. High blood pressure and high cholesterol are two of the most significant risk factors. Fortunately, statins are an effective way to reduce cholesterol, and valsartan may be a valuable add-on to prevent stroke in those patients with coronary artery disease.

Next week, we will continue our discussion of medications, exploring a surprising finding with combination therapy and the effects of lifestyle modifications.

This is part one of a two-part series on strokes.

Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, go to the website www.medicalcompassmd.com and/or consult your personal physician.