Development and validation of the mini-osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to vertebral fractures. Osteoporosis Quality of Life Study Group

The objective of the study was to evaluate a shortened osteoporosis quality of life questionnaire (OQLQ) in osteoporotic women with back pain due to v ertebral fractures. From the longer 30-item OQLQ (four to nine items per do main) we created the mini-OQLQ by choosing the two items with the highest i mpact in each of five domains (symptoms, physical function, activities of d aily living, emotional function, leisure). We administered the OQLQ, the Si ckness Impact Profile, the SF-36 and the Brief Pain Index to patients at ba seline, after 2 weeks and after 6 months. The intraclass correlations betwe en baseline and the 2-week follow-up for the five mini-OQLQ domains ranged from 0.72 to 0.86. Cross-sectional correlations between the domains of the mini-OQLQ and other health instruments were moderate to large (0.35-0.80) a nd greater than predicted. The mini-OQLQ items showed moderate to large cor relations with items omitted from the shortened questionnaire (0.44-0.8). C orrelations between the OQLQ domains and the other three instruments were g reater than those of the mini-OQLQ, and partial correlations between OQLQ i tems omitted from the mini-OQLQ and the other three instruments after consi dering mini-OQLQ items were substantial (0.19-0.71) and statistically signi ficant. Sample sizes of less than 200 per group should be required to detec t minimally important differences in parallel-group clinical trials. Longit udinal correlations between the mini-OQLQ and the other measures were often significant but generally lower than predicted (0.10-0.49). The partial co rrelations revealed that the omitted items explained a significant portion of the longitudinal variance in each domain. We conclude that in a selected group of patients with back pain caused by vertebral fractures, the mini-O QLQ demonstrated good discriminative and adequate evaluative properties. Th e mini-questionnaire should be useful in clinical settings.