Validation of the Portuguese version of ID-Migraine.

BACKGROUND: Migraine is a highly prevalent disorder that imposes an important burden of disability to patients and has social and economic impact in developed countries. A good screening tool for migraine diagnosis is useful to improve disease identification and therapeutic approaches, hopefully reducing the burden of migraine. Although Portuguese is currently the sixth most spoken language in the world, no migraine screening instrument exists in Portuguese.

OBJECTIVE: To validate the Portuguese version of ID-Migraine.

METHODS: Consecutive adults of 2 headache outpatient clinics in Lisbon, Portugal fulfilled the Portuguese version of ID-Migraine before evaluation by a trained neurologist in clinic, blinded to the questionnaire's results. The gold standard was the neurologists' clinical diagnosis, according to the International Classification of Headache Disorders, 2nd edition. A subset of patients was randomly selected to revaluation, in order to determine test-retest reliability. The validity measures of the test were calculated.

RESULTS: A total of 142 patients were included, 83.8% of which women, with an age average of 39.2 years. Clinical diagnosis of migraine was made in 63.4% of the patients. The Portuguese version of ID-Migraine presented a sensitivity of 0.94 (95% CI 0.87-0.97), specificity of 0.60 (95% CI 0.46-0.73) and a positive predictive value of 0.80 (95% CI 0.71-0.87). Calculated Cronbachs' alpha was 0.78 and kappa coefficient 0.60.

CONCLUSIONS: The Portuguese version of ID-Migraine was of easy and rapid application and well accepted by patients. Its validity measures were identical to the 3 other versions of the same questionnaire - English (original), Italian, and Turkish. The Portuguese version of ID-Migraine is a valid screening tool for migraine, the first that can be used in Portuguese speaking communities although the low literacy rates in some of these countries may prevent its generalized application throughout the world.