WASHINGTON – Noncephalic pain is associated with higher likelihood of progression from episodic migraine to chronic migraine, and pain comorbidities at noncephalic locations are common with migraine regardless of headache frequency, according to findings from the CaMEO study.
The study was presented during the poster session of the American Headache Society’s annual meeting by Dr. Ann I. Scher, deputy director and professor at the Uniformed Services University of the Health Science, Bethesda, Md.
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The CaMEO (Chronic Migraine Epidemiology and Outcomes) study was initiated in the fall of 2012 as a prospective, web-based study that surveyed individuals with migraine and chronic migraine using “cross-sectional modules embedded in a longitudinal design.”
The investigators used the survey’s Comorbidity/Endophenotype module to study 12,810 individuals with migraine, of whom 8,908 were randomized and completed the second assessment snapshot module 3 months after baseline.
Overall, 8,139 (91.4%) had episodic migraine and 769 (8.6%) had chronic migraine. At baseline, subjects were asked to identify noncephalic pain sites by location (head, face, neck/shoulders, back, arms/hands, legs/feet, chest, abdomen/pelvis, or other), frequency of pain (0-4 scale ranging from “never” to “always” experiencing pain), and intensity of pain (0-10 scale of “no pain” to “worst pain imaginable”).
At 3 months, the investigators followed up with patients to determine if they still had either chronic or episode migraine, and performed multivariate binary regression analysis to determine if the noncephalic pain sites were an indicator of progression from episodic to chronic migraine, based on the aforementioned factors as well as sociodemographic ones.
Subjects with episodic migraine at baseline tended to stay that way, with 278 (3.4%) progressing to chronic after 3 months. However, 385 (50.1%) of those with chronic migraine at baseline were still classified as such after 3 months, meaning nearly half went from chronic to episodic. Regression models indicated that while noncephalic pain is common for both episodic and chronic migraine, after adjustment for pain site scores and sociodemographic factors, the odds of progressing from episodic to chronic migraine increases by about 30% for each noncephalic pain site (odds ratio, 1.30; 95% confidence interval, 1.21-1.40). For those already experiencing chronic migraine, the odds of remaining that way after 3 months increase by about 6% with each noncephalic pain site (OR, 1.06, 95% CI, 0.97-1.16).
In the CaMEO study, the mean age of subjects with episodic migraine was 40.6 years versus 41.0 years for those with chronic migraine. Both cohorts were mostly female, too: 73.8% for episodic and 81.1% for chronic. Both cohorts were mostly white – 83.3% and 87.5%, respectively – while 45.9% of those with episodic and 34.9% of those with chronic migraine had at least a bachelor’s degree–level education. Sixty-six percent of those with episodic and 56.4% of those with chronic migraine held full-time employment at baseline.
The CaMEO study was sponsored by Allergan. Lead author Dr. Scher has received honoraria from Allergan and grant support from Congressionally Directed Medical Research Programs and the Center for Neuroscience and Regenerative Medicine, and is on the editorial boards of Cephalagia and Pain Medicine.