Response to Botulinum Toxin Type-A in Patients with Refractory Chronic Migraine

Background: Due to its debilitating nature, refractory chronic migraine (RCM) is primarily associated with a poor quality of life. However, controversy remains regarding the efficacy and safety of botulinum toxin for treating RCM. Objectives: The aim of this study was to investigate the efficacy of botulinum toxin type A (BTX-A) in patients with RCM. Methods: In this retrospective cross-sectional study conducted between April 2016 and March 2021, RCM patients who were resistant to conventional therapies and received BTX-A injections were followed for 7 and 14 days after the injection. The outcome variables included the frequency, duration, and severity of migraine episodes, the need for painkillers, adverse events, and the patient's perceived improvement. Data were analyzed using SPSS. Results: In total, 52 RCM patients with a mean age of 31.84 years participated, of whom 69.2% were female. The frequency of migraine episodes decreased from a baseline of 9.84 to 3.94 and 1.25 at 7 and 14 days after injection, respectively (P < 0.001). The duration of migraine episodes dropped from 3 hours at baseline to 1.74 and 1.17 hours at 7 and 14 days post-BTX-A injection, respectively (P < 0.001). The severity of migraines alleviated from 8.07 at baseline to 6.48 and 3.38 at the respective follow-up times (P < 0.001). The need for painkillers also decreased at follow-ups (P < 0.001). Males achieved better treatment outcomes regarding the frequency of migraine episodes and the need for medications compared to females following BTX-A treatment (P < 0.05). Frontotemporal and frontotemporal-occipital headache distributions showed fewer migraine episodes, shorter duration, less severity, and lower need for painkiller consumption compared to other migraine types (P < 0.05). The most common adverse event was localized pain (42.3%), followed by itching (25.0%). A considerable number of patients felt improvement. Conclusions: According to our findings, BTX-A is a safe and well-tolerated treatment for patients with RCM. Validation of these results requires adequately precise studies investigating the effect of BTX-A in detail.