A 12-item case-finding tool correctly classifies most people with migraine and chronic migraine, according to research published in the March issue of Cephalalgia. The tool, which is called Identify Chronic Migraine (ID-CM), classifies migraine with a sensitivity of 83.5% and a specificity of 88.5% and chronic migraine with a sensitivity of 80.6% and a specificity of 88.6%.
Migraine, and chronic migraine in particular, is underdiagnosed and undertreated, said Richard B. Lipton, MD, Vice Chair of Neurology at Albert Einstein College of Medicine in the Bronx, New York, and colleagues. The authors sought to develop a valid case-finding tool for chronic migraine that would be applicable to people who reported severe headache.
Richard B. Lipton, MD
The researchers developed their instrument in four stages. In the first stage, they convened an international panel of expert clinicians and researchers that selected potential items from existing diagnostic tools. The panel also suggested additional items for consideration. In stage two, Dr. Lipton and colleagues conducted cognitive debriefing interviews with people with chronic migraine to determine whether the latter understood the tool’s instructions and whether the items were worded properly.
Researchers also administered the items that had emerged from stage two, along with a set of patient-reported outcome measures, to a Web-based sample of 1,600 people with migraine or other severe headache. Data from this stage enabled them to perform a psychometric assessment of the new tool’s candidate items. Finally, in stage four, investigators compared diagnoses assigned using ID-CM with independent diagnoses assigned by headache experts using a semistructured diagnostic interview for migraine. Patients who had participated in the third stage of development were invited to participate in this stage.
The final version of ID-CM includes two questions about headache frequency, four about headache symptoms, two about medication use, two about whether headache interferes with activities, and two about whether headache interferes with making plans.
“ID-CM has been rigorously evaluated and has strong psychometric properties and high classification accuracy, both for migraine and chronic migraine,” said Dr. Lipton. “Compared with other well-known and highly regarded screening and diagnostic tools for various diseases/disorders, the classification accuracy of ID-CM was both absolutely and relatively strong....The simplicity and accuracy of ID-CM will enable health care professionals with or without training in neurology, pain, or headache to correctly identify the majority of patients with migraine or chronic migraine,” Dr. Lipton said. “Clinicians will then be able to accurately diagnose or refer affected patients to specialists for effective treatment that will reduce the burden of illness experienced by those with migraine and chronic migraine.”