Failure of preventive treatments in migraine: an observational retrospective study in a tertiary headache center.

BACKGROUND: Although the criteria for acute migraine treatment and prevention have been well described, there are still unmet needs, general underuse and low benefits of preventive drugs. The aim of the present study was to retrospectively observe the short-term effect of preventive treatment in a cohort of migraine patients attending a tertiary headache center, using data from electronic medical records. METHODS: This was an observational retrospective cohort study based on data collected in a tertiary headache center. Data were extracted from an electronic dataset collected from January 2009 to December 2019. The main selection criteria were as follows: age of 18-75 years; diagnosis of migraine without aura (MO), migraine with aura (MA) or chronic migraine (CM); a control visit 3 months after the first access; and prescription of preventive treatment with level of evidence 1 as reported by Italian guidelines. As the primary outcome, we considered the change in the frequency of headache at the follow-up visit. Then, as secondary outcome measures, we used disability scores, intensity of headache, and allodynia. As predictive factors, we considered age, migraine duration, sex, headache frequency, allodynia, anxiety and depression at baseline, and comorbidity with fibromyalgia. RESULTS: Among the 6430 patients screened, 2800 met the selection criteria, 1800 returned to the follow-up visit, 550 withdrew because of adverse events, and 1100 were included the analysis. One hundred thirty-four patients had a frequency reduction of 50% or more. Flunarizine was used for less severe migraine, with a better effect compared to those of other drugs (odds ratio: 1.48; p: 0.022). Low headache frequency and absent or mild allodynia predicted a better outcome. CONCLUSIONS: The mild effect of preventive drugs on migraine features and even the number of patients who were lost to follow-up or dropped out because of adverse events confirm that in severe and chronic patients, the first line of prevention can only delay a more focused therapeutic approach.