The psychometric properties of the Comprehensive Headache-related Quality of life Questionnaire (CHQQ) translated to Serbian

BACKGROUND The Comprehensive Headache-related Quality of life Questionnaire (CHQQ), is a recently developed and validated instrument, intended for measuring quality of life of patients with all headache types. Currently no validated headache-specific quality of life questionnaires are available in Serbian. The aim of this study was to translate the CHQQ from Hungarian to Serbian, to make necessary cultural adaptations and to test its psychometric properties in a sample of outpatients with headache. METHODS The CHQQ was translated and adapted according to internationally accepted guidelines, and then tested on a sample of 216 Serbian headache patients (171 females and 45 males, mean age 42.3 years/SD 13.35; range 18-75). The majority of patients suffered from episodic tension-type headache (TTH); 27 (12.5 %) had episodic migraine. We calculated the internal consistency (Cronbach's alpha), criterion validity (correlations of individual items, dimensions and whole questionnaire with the clinical characteristics of headache), convergent validity (correlations of the abovementioned scores with results of other instruments measuring headache severity and impact), and discriminative validity (comparison of the scores in the two diagnostic groups) of the CHQQ. We used factor analysis to explore the underlying construct. RESULTS The Serbian translation of CHQQ showed excellent internal consistency, both for the whole instrument (Cronbach's alpha 0.937) and its dimensions. The validity of the instrument in all aspects (criterion, convergent and discriminative validity) was also excellent when the whole sample and the subgroup of patients with TTH were analyzed, while the results for patients with migraine were less favorable. Factor analysis suggested the existence of a single dimension in this sample. CONCLUSIONS The Serbian translation of CHQQ is as reliable and valid specific instrument for measuring headache-related quality of life in patients with TTH and probably in patients with migraine.