Migraine Increases Risk of Vascular Disease, but Risk Still Low

People with migraine—especially people who experience aura before headache—are known be at increased risk of ischemic stroke and cardiovascular disease. What isn't well known, however, is 1) whether these increased risks apply to people who have migraines without aura; and 2) whether migraine is an independent risk factor for vascular disease or merely a marker for well-known risk factors, like diabetes.

A new survey study of more than 11,000 people, the results of which are published online in the journal Neurology, essentially answers "yes" to these issues.

1. People who experience migraine without aura have increased risks of heart attack and peripheral vascular disease—but, surprisingly, not stroke. These increased risks, however, are smaller than those for people who experience migraine with aura.
2. All people who experience migraine (with or without aura) are more likely to have been diagnosed with diabetes, hypertension, or high cholesterol levels—all well-known vascular risk factors.
3. But, on the basis of a multivariate analysis (including control for triptan use*), migraine also appears to be an independent risk factor for vascular disease.

The absolute rates of vascular events and vascular risk factors, discovered by the authors, are tabulated here:

Condition	Controls (Without Migraine)	All Migraineurs	Migraine With Aura	Migraine Without Aura
Heart attack, %	1.9	4.1	5.5	3.4
Stroke, %	1.3	2.0	3.8	1.1
Claudication, %	0.9	2.6	4.2	1.8
Diabetes diagnosis, %	9.4	12.6	13.8	12.0
Hypertension diagnosis, %	27.8	33.1	35.7	31.9
High cholesterol level, %	25.6	32.7	33.8	32.2
Smoking, %	14.2	15.8	16.3	15.5
Mean Framingham risk score	8.5	10.7	11.0	10.6

The mean Framingham risk scores for all 3 groups of migraineurs were significantly higher (P = .001) than the mean score for the surveyed control population.

The authors, who represent industry (Merck**) and academia (Albert Einstein, Brigham and Women's), stress that a history of migraine in patients should prompt a search for modifiable cardiovascular risk factors. They also postulate that migraine itself may predispose to vascular disease by compromising the function of vascular endothelium.

The question of whether triptan use or migraine prevention (eg, with beta blockers) alters the risk of vascular events is raised by Diener and Harrer in an accompanying editorial. They propose that the necessary length of a prospective study would be prohibitive (eg, >10 years). They also wonder whether the relatively low risks of vascular events in migraineurs would justify the effort and expense.

* Recently the same authors (Bigal et al) reported that tripan use is lower in migraineurs with cardiovascular risks, "suggesting that doctors and/or patients fear using tripans in individuals at risk."

** Merck makes Maxalt (rizatriptan).

Depiction of classic fortification spectra of migraine aura, as depicted by Dr. Gowers in 1907.