An outcome measure for Japanese people with chronic low back pain

Study Design. Development of a nationwide patient-based outcome measure for patients with chronic low back pain (CLBP). Objective. The purpose of this study was to develop and introduce a new means of measuring outcomes for Japanese individuals with CLBP (the Japan Low Back Pain Evaluation Questionnaire [JLEQ]), and to examine its validity and reliability by comparison with the Roland-Morris Disability Questionnaire (RDQ). Summary of Background Data. CLBP is a serious problem affecting the health and welfare of workers, especially laborers., The severity and disability it causes vary depending on cultural background and the psycho-emotional aspect of the patients. Methods. The following items were tested for the JLEQ and the RDQ using psychometric analyses: content validity, construct validity, criterion validity, internal-consistency reliability, and test and retest reliability. Results. A total of 195 patients with CLBP participated in this study. There were no floor and ceiling effects in the JLEQ. Cronbach's alpha coefficient was 0.971 and 0.893 for the JLEQ and RDQ, respectively. The test-retest interclass correlation coefficient in the JLEQ was 0.886, indicating good test-retest reliability. Categorical principal component analysis showed that the construct structure consisted of 3 item clusters in the JLEQ. The factor loading patterns indicated that the JLEQ items were separated into 3 domains, i.e., a moderately loaded group, a less loaded group, and psychological conditions. The degree of correlation between the question items in the JLEQ and RDQ was evaluated using Akaike Information Criteria. Conclusion. The JLEQ was shown to be a valid and reliable questionnaire scale for measurement of patient-based outcomes in CLBP patients.