Translation and study of validity and reliability of Persian-version of headache disability inventory (HDI) in patients with chronic headache

Abstract

• Background To evaluate and manage headache related disabilities among Persian-speaking patients, a headache dedicated disability index is missing. The objective of this cross-cultural study is to translate and determine validity and reliability of the Persian-version of the headache disability inventory (HDI). • Methodes The original version of the questionnaire was translated and cultural adapted to Persian language using published international guidelines. Two hundred and fifty patients with chronic headache were enrolled into study. Subjects were supposed to fill the HDI index. Face validity was carried out with 20 patients. Content validity, factor analysis, and convergent validity were conducted on 250 patients. To carry out the long-term and the short-term test-retest reliability a total of 30 patients, selected from the target population, completed the questionnaire again 1 week later, and 1month later, in the same manner as the first one. • Results Each point which was mentioned by the subjects who filled the questionnaire for evaluation of the face validity was discussed in the authors’ group and required modifications were applied. The CVI scoring in terms of simplicity, relevance and clarity was equal to 0.85, 0.99 and 0.97 respectively. The content validity ratio (CVR) was 1 for all questions in terms of necessity. The results of factor analyzes showed that the theoretical structure of the questionnaire and the correlation of questions with both functional and emotional domains were acceptable in the studied population and our index has a good fit. The reliability of internal consistency with Cronbach's alpha for the entire questionnaire as well as the functional and emotional domains were evaluated, that 0.91 for the questionnaire and 0.82 for the functional domain and 0.86 for the emotional domain was assessed. In evaluating the convergent validity, the negative correlations between corresponding domains were expected and due to achieved results significant negative correlations were obtained, and approves the existence of the convergent validity between two questionnaires. • Conclusion The findings of this study suggest that the Persian-version of the HDI is a reliable and valid instrument to measure the quality of life of the people suffering from headache in both emotional and functional subscales and designing treatment strategies, and to use in other neurology based research projects as regards has good factor structure.