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.