PND55 IMPACT OF BAROMETRIC PRESSURE CHANGES AND PROPHYLACTIC MIGRAINE MEDICATION USE ON THE OCCURRENCE OF SEVERE MIGRAINES: A CASE-CROSSOVER STUDY USING LINKED WEATHER AND CLAIMS DATA

Severe migraine patients may use prophylactic medications to reduce the number or severity of their headaches. Patients often experience a migraine after a meteorological change, and the association between these events and occurrence of severe migraines for patients with and without prophylactic use was examined. A case-crossover design was implemented utilizing the IBM® MarketScan Weather Database, which links weather data with administrative claims data using metropolitan statistical area (MSA)-specific daily weather data and the patients’ MSA from administrative claims. Patients with ≥1 severe migraine (a migraine-related inpatient or emergency room visit) between 2015 and 2017 were selected. The date of the first severe migraine was the ‘case date.’ Patients were stratified by whether or not they had a pharmacy claim for medication commonly used for migraine prophylaxis between 180 days before and 7 days after the case date. Three control dates were selected for comparison: 7 days before, 28 days before, and 7 days after the case date. Weather conditions on the case date versus control dates were compared via conditional logistic regression model to determine if weather conditions were predictive of a severe migraine for patients with or without prophylactic. The study included 34,776 patients who met the inclusion criteria. Of these, 17,508 patients used a prophylactic, while 17,268 did not. The conditional logistic regression model revealed that for each 1 inHg increase in daily maximum barometric pressure, the odds of severe migraine increased by 9% (OR: 1.09; p=0.025) for patients with prophylactic, and by 56% (OR: 1.56; p<0.001) for those without, controlling for other weather conditions. This study utilized a novel linked weather and administrative claims database to provide real-world evidence of the impact of prophylactic medication use on severe migraine events after changes in barometric pressure.