Increased efficacy of regularly repeated cycles with OnabotulinumtoxinA in MOH patients beyond the first year of treatment.

BACKGROUND: Chronic migraine is one of the most common diseases in the world and it is often associated with medication overuse that can worsen the headache itself. Thus, it is important to adopt effective therapies to relieve pain and improve patients' quality of life. The PREEMT studies have already demonstrated the effectiveness of OnabotulinumtoxinA in the treatment of chronic migraine. With this in mind, the aim of this real life observation has been to assess the clinical improvements as well as the impact on the quality of life of patients being regularly (every three months) administered this therapy.

METHODS: Data from 66 chronic-migraineurs treated with OnabotulinumtoxinA after failing previous therapies were collected. Only 57 of them were analysed since 9 discontinued the therapy due to administrative reasons. For every patient enrolled, headache frequency, analgesic consumption, pain severity, headache-related disability, health-related quality of life as well as anxiety and depression symptoms were collected through the Headache Index (HI), analgesic consumption rate in one day (AC), VAS score, Headache Impact Test (HIT-6) and the Short Form (36) Health Survey questionnaire Version 2 (SF-36®), Zung Self-Rating Anxiety Scale (ZUNG-A) and Zung Self-Rating Depression Scale (ZUNG-D), respectively. All the changes vs baseline (Tx vs T0) were expressed as mean ± SD and analysed with a one-way ANOVA plus non-parametric Wilcoxon test, that was used for paired data for each subject.

RESULTS: As the number of injection increased, those patients injected regularly observed a statistically significant reduction in the headache frequency, pain intensity, headache disability score and an overall marked improvement in patients' quality of life. There was also a significant reduction in anxiety and depressive symptoms as for the ZUNG-A and ZUNG-D scales scores. At any time point, those patients who stopped the therapy worsened their overall conditions as confirmed by quality of life parameters.

CONCLUSIONS: This study outpoints that OnabotulinumtoxinA treatment is an effective treatment to reduce the headache-related disability and improve patients' quality of life when patients are treated regularly every three months and consistently overtime. Therapy discontinuation leads to a general worsening of health-related quality of life. Long term treatment over one year confirms a consistently positive and sustained trend of improvement with a high safety profile.