Japanese orthopaedic association back pain evaluation questionnaire. Part 2. Verification of its reliability

Background. The project to develop a new Japanese Orthopaedic Association (JOA) score rating system for low back disorders, the JOA Back Pain Evaluation Questionnaire (JOABPEQ), is currently in progress. Part 1 of the study selected 25 candidate items for use on the JOABPEQ. The purpose of this current Part 2 of the study was to verify the reliability of the questionnaire. Methods. A total of 161 patients with low-back disorders of any type participated in the study. Each patient was interviewed twice at an interval of 2 weeks using the same questionnaire. The reliability of the questionnaire was evaluated by determining the extension of the kappa and weighted kappa coefficients. Results. Both kappa and weighted kappa were more than 0.50 for all but one item, which was 0.48. The lower 95% confidence interval exceeded 0.4 in all but two items, which was 0.39. This implied that the test-retest reliability of JOABPEQ was acceptable as a measure of outcome. Conclusions. The tentative questionnaire of the JOABPEQ with 25 items was confirmed to be reliable enough to describe the quality of life of patients who suffer low back disorders.