Hungarian adaptation of a questionnaire for determining depression-specific quality of life

INTRODUCTION: The Quality of Life in Depression Scale (QLDS) is a widely used outcome measure available in a large number of languages. No measure of quality of life was available for use with depressed patients in Hungary and a decision was taken to adapt the QLDS for this purpose. The adaptation of a questionnaire for use in a new language involves three stages; translation, testing for face and content validity and assessment of the translated measure's psychometric properties. OBJECTIVES: To adapt the QLDS for use in Hungary and to evaluate its psychometric properties. METHOD: The dual panel method was used to translate the QLDS into Hungarian. The translation was tested for face and content validity by interviews conducted with depressed patients. Finally, a test-retest postal survey was conducted to determine internal consistency, reproducibility and construct validity. RESULTS: Interviews conducted with 25 patients indicated that the QLDS was an appropriate measure and that it was well accepted and completed. The postal survey ( n = 50) showed that the measure had good internal consistency (Cronbach's alpha-coefficients were 0.95 at both administrations) and that the test-retest reliability (0.89) indicated good reproducibility with limited random measurement error. Correlations of QLDS scores with those for the Nottingham Health Profile sections were as expected, providing evidence of convergent and divergent validity. CONCLUSION: Given the acceptability of the Hungarian version of QLDS to depressed patients and the excellent psychometric properties of the adapted questionnaire it is concluded that the adaptation was successful. The measure is suitable for use in clinical practice and studies involving depressed patients in Hungary.