Reliability and Validity of the Persian HIT-6 Questionnaire in Migraine and Tension-type Headache.

Objective: Headache Impact Test (HIT-6) measures the impact headaches in a 1-month period. We validated the Persian translation of HIT-6, compared the HIT-6 psychometric analysis between migraine and tension-type headache (TTH) patients, and evaluated the capability of HIT-6 to differentiate between TTH, chronic migraine, and episodic migraine. Methods: Qualified participants, including 274 patients diagnosed with migraine or TTH, were required to complete HIT-6, SF-36v2, and a symptoms questionnaire on their first visit. At 3 and 8 weeks from first visit, participants completed HIT-6. Internal consistency (Cronbach's alpha) and test-retest reproducibility (Pearson's correlation coefficient) were used to assess reliability. Convergent validity was also assessed. Results: Tension-type headache, episodic, and chronic migraines included 24.5%, 61.9%, and 13.6% of the participants, respectively. Internal consistency among all patients, TTH, and migraine in the first visit were 0.74, 0.77, and 0.73, respectively. Test-retest reliability for HIT-6 between visit 1 and 2 showed a moderate level of correlation (r = 0.50). Convergent validity and also item total correlation were acceptable. There was no significant difference in HIT-6 total score between TTH and migraine. Conclusion: Persian HIT-6 is a valid and reliable questionnaire for the evaluation of headache. However, it cannot differentiate between chronic migraine, episodic migraine, and TTH in Iranian population.