Validation of the Quality of Life Questionnaire of the European Foundation for Osteoporosis-31 in Spanish postmenopausal women

Objective The Quality of Life Questionnaire of the European Foundation for Osteoporosis-31 (QUALEFFO-31) is a reliable and validated questionnaire that assesses quality of life in osteoporotic women. Our objective was to analyze the reliability and validity of the Spanish version of QUALEFFO-31 and its ability to discriminate between women with osteoporosis and women without osteoporosis in a Spanish postmenopausal population. Methods One hundred eighteen women (aged 50-65 y) completed the Spanish version of QUALEFFO-31. Bone mineral density was measured by dual-energy x-ray densitometry. Internal consistency and test-retest reliability were analyzed. Concurrent validity of QUALEFFO-31 was evaluated using Spearman's rank correlation coefficient with the 36-item Short-Form Health Survey (SF-36). To determined responsiveness, we analyzed mean differences between osteoporotic and nonosteoporotic women and performed receiver operating characteristic curve analysis. Results The Spanish version of QUALEFFO-31 has shown excellent test-retest reliability with a high intraclass correlation coefficient for all its domains, especially for the total score (0.988; P < 0.001), and good internal consistency with optimal Cronbach alpha values in all scales (0.70-0.90). In concurrent validity analysis, QUALEFFO-31 total score showed a high and negative correlation with several scales of the SF-36 (P < 0.001). In responsiveness analysis, significant differences in the pain (P = 0.002) and QUALEFFO-31 total score (P = 0.004) scales were found between osteoporotic and nonosteoporotic women. No differences in areas under the receiver operating characteristic curve were found between the QUALEFFO-31 and the SF-36 scales. Conclusions The Spanish version of QUALEFFO-31 has good internal consistency, concurrent validity, and test-retest reliability, with satisfactory general psychometric properties, and is a valid tool for discriminating between osteoporotic and nonosteoporotic postmenopausal women aged 50 to 65 years.