More than one in seven people have migraine in Denmark, costing billions of kroner in treatment and lost earnings. Nevertheless, little is known about which types of migraine medicine are effective for each individual. By linking data from the Danish National Prescription Registry with information about symptoms among people with migraines, researchers have now clarified that people – perhaps naturally enough – only buy the medicine if it is effective. This new knowledge can identify the people for whom the medicine is not effective to enable them to find alternative treatment.
Migraine is an invisible disease – at least for those who do not experience it. It is not fatal and leaves no visible scars, but the threat constantly lurks in the minds of the people with migraine. People with chronic migraine experience it 15 days per month on average and take considerably more sick leave than people without migraine. However, there are excellent and effective types of migraine medicine. The challenge is to find out which one works best for each individual.
“Measuring whether migraine medicine is effective is difficult and time-consuming because it the assessment is subjective. We therefore try to find objective ways to measure whether medicine actually works. Our research shows that monitoring people’s purchases by using the Danish National Prescription Registry provides a good measure of whether the medicine is effective. We can use this to easily find those who need another type of medicine to become migraine-free so they can get healthier and so we can minimize the number of sick days,” explains Thomas Folkmann Hansen, Associate Professor, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen and Research Leader, Danish Headache Center, Rigshospitalet, Copenhagen.
The art of measuring effectiveness
Linking data from the Danish National Prescription Registry and interviews with more than 1900 people with migraine enabled the researchers to find an association. The people with migraine were interviewed about their symptoms and well-being, and their statements were then linked with the number of times they purchased the medicine prescribed.
“Basically, the results show that the number of people reporting that the medicine is effective increases in accordance with the number of purchases. We found that 73% of the people with migraine who reported that the triptans were effective had bought them at least 10 times.”
Triptans are rapid and usually effective medicine, but people differ: not everyone benefits from the same triptans, and some do not benefit at all. The researchers therefore also investigated the purchases of medicine intended to prevent migraine. Unfortunately, these results were less clear.
Although the number of purchases of preventive medicine appeared to be similarly associated with the effectiveness as with the triptans, the statistics were not robust enough, because fewer people use preventive medicine, so more research is required before we can conclude that there is an association.
Tools for precision medicine
This new knowledge is important, because people with migraine often try several types of medicine before they find an effective one. Denmark’s usual clinical practice for neurologists is to try at least three different triptans, but assessing which ones work best can often be difficult. The new knowledge may be important in determining the optimal treatment.
“Patients’ own version of their medical history is important evidence. However, our new method of measurement can clearly help in supporting this individual experience when doctors plan the optimal treatment for a specific patient.”
Migraine is the third most common disease in Denmark, so many people depend on rapid and effective treatment. From both human and socioeconomic perspectives, reducing the number of sick days by merely 5–10% will result in a gain of many hundreds of millions days annually.
The study establishes that the Danish National Prescription Registry, which is based on the databases in individual pharmacies, is a very good source for identifying the treatment response to different types of migraine medicine and therefore to precision medicine for individuals. If we can determine that people purchase the same medicine 10 times, this clearly indicates that it reduces the number of migraine attacks or, more importantly for many people, reduces their severity. And, perhaps most significantly, this method can identify the people for whom the medicine does not appear to work, and then we can focus on trying to find other treatments.
”Predicting treatment response using pharmacy register in migraine” has been published in The Journal of Headache and Pain. A main author is Thomas Folkmann Hansen, Associate Professor, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen and Senior Research Manager, Danish Headache Center, Rigshospitalet, Copenhagen.