Validation of a Portuguese version of the four-item Migraine Interictal Burden Scale.

Background: Migraine is the most common neurological disorder and the second leading cause of disability. While the impact of migraine on daily life is often assessed by the frequency and intensity of attacks, the impairment between episodes is frequently overlooked. The four-item Migraine Interictal Burden Scale (MIBS-4) is a tool that can provide information and help in the evaluation of interictal disability.

Objective: To adapt and validate a translated version of the MIBS-4 for the Portuguese population.

Methods: A prospective, multicentric observational study was conducted between July 2023 and February 2024 in six tertiary headache centers across Portugal. The MIBS-4 was translated and back-translated to obtain a consensus version. The scale was administered to 459 patients with migraine, and its psychometric properties were assessed through correlations with established measures, including the Migraine Disability Assessment Scale (MIDAS), 12-item Short Form Survey (SF-12), and Hospital Anxiety and Depression Scale (HADS).

Results: A total of 459 patients were evaluated, including 430 women (93.7%), with an average age of 45.06 years. The MIBS-4 demonstrated good internal consistency with a Cronbach's alpha of 0.84 (95% confidence interval 0.81-0.86) and significant correlations with the MIDAS (r = 0.304, p < 0.001), SF-12 (r = 0.483, p < 0.001), and HADS (r = 0.211, p < 0.001), confirming its reliability and construct validity.

Conclusion: This analysis showed that the Portuguese version of the MIBS-4 showed identical psychometric properties to the original scale and can effectively assess interictal disability in patients with migraine in Portuguese speaking populations. Its validation provides a valuable tool for clinical practice and research, enabling improved assessment of migraine burden and contributing to better patient care in lusophone countries.