Migraine linked to increased risk of Bell's palsy

Patients with migraine have almost double the risk of developing Bell's palsy compared with those without migraine, researchers report.

Their observational cohort study of patients with migraine and matched controls found that the association between migraine and Bell's palsy, an acute, ipsilateral facial nerve paralysis that results in weakness of the platysma and muscles of facial expression, was not affected by sex or migraine subtype.

According to Medscape (http://www.medscape.com/viewarticle/836860), The results suggest that physicians should ask patients about migraine, study author Shuu-Jiun Wang, MD, deputy director, Neurological Institute, Taipei Veterans General Hospital, and chairman, Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, told Medscape Medical News.

"In clinical practice, in addition to hypertension, diabetes, and pregnancy, migraine history should be traced in patients with Bell's palsy," said Dr Wang. He stressed that this is especially important in young people, who usually don't have hypertension or diabetes.

Their findings were published online December 17 in Neurology.

Researchers used data from the Taiwan National Health Insurance Research Database (NHIRD) to assemble two cohorts aged 18 years and older: (1) all patients diagnosed with migraine (migraine with aura, migraine without aura, and migraine unspecified) from January 2005 to December 2009 and (2) matched controls without migraine or other headache extracted from a random sample in NHIRD.

Participants with Bell's palsy at baseline were excluded from the study, as were those in whom migraine and Bell's palsy were both diagnosed within 30 days.

To minimize baseline differences between the patients with migraine and participants without migraines, researchers used propensity score matching. For each patient in the migraine cohort, they identified one control participant with similar demographic characteristics, matched in terms of age and propensity score for the likelihood of a migraine diagnosis.

The propensity score–matched analysis included 136,704 participants in each of the migraine and control cohorts.

After a mean follow-up of 3.2 years, 671 persons in the migraine group and 365 in the control group were newly diagnosed with Bell's palsy. The incident rates were 158.1 and 83.2 per 100,000 patient-years, respectively.

This incidence of Bell's palsy in the control group was higher than previously reported (13.1 to 53.3 per 100,000 person-years). This discrepancy, said Dr Wang, might be explained by the accessibility and global coverage of Taiwan's National Health Insurance plan.

Migraine is quite common, with an annual global prevalence of about 10%. It affects more females than males. The male-to-female ratios of Bell's palsy in this study were 1.4 to 1 in the migraine cohort and 1.1 to 1 in the control cohort.

Patients with migraine had greater risk for Bell's palsy (hazard ratio, 1.91; 95% confidence interval, 1.68 - 2.17; P < .001). The association between migraine and Bell's palsy was similar with and without propensity score matching.

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