Background: The Short Form-36 (SF-36) and Migraine Disability Assessment (MIDAS) questionnaires are two of the most commonly used tools to measure outcomes in people suffering from headaches. Nevertheless, little is known about their interrelationship in patients with headache.
Objectives: The aim of this study was to investigate the interrelationship between SF-36 and MIDAS questionnaires in patients with migraine.
Methods: We enrolled 231 patients with migraine (male/female: 43/188, mean age 35.3+/-8.1) who visited our headache clinic. They completed the SF-36, MIDAS, and a headache intake form.
Results: The correlation coefficients between the MIDAS score and 8 domains of the SF-36 ranged from -0.30 for the mental health domain to -0.53 for the social functioning domain (P<0.01). Canonical correlation analysis showed that the overall overlap between the 2 instruments was moderately strong (canonical correlation coefficients r=0.707 and 0.572). The overall measured redundancies for MIDAS and SF-36 scales in this study were 35.4% and 11.5%, respectively. The stepwise linear regression model showed that the social functioning domain alone explained 27.9% of variance in the MIDAS scores. Bodily pain, physical functioning, and general health domains added an additional 11.4% of the explained variance in the regression model.
Conclusion: Despite the fact that these two measures were considerably correlated, the MIDAS and SF-36 were found to measure different aspects of the impact of headache for the sample investigated. The MIDAS questionnaire does not cover the emotional domain; therefore, an accompanying psychological questionnaire might help assess the outcome for headache studies.