Roland-Morris Disability Questionnaire, Oswestry Disability Index, and Quebec Back Pain Disability Scale: Which Has Superior Measurement Properties in Older Adults With Low Back Pain?

OBJECTIVE: To examine the validity, reliability, and responsiveness of 3 commonly used question-naires for assessing physical function (ie, Oswestry Disability Index [ODI], Quebec Back Pain Disability Scale [QBPDS], and Roland-Morris Disability Questionnaire [RMDQ]) in older patients undergoing chiropractic care for low back pain (LBP). DESIGN: Head-to-head clinimetric comparison. METHODS: Patients completed the ODI, QBPDS, and RMDQ at baseline and after 2 weeks of treatment. Reliability was evaluated for internal consistency (Cronbach alpha), test-retest reliability (interclass correlation coefficient [ICC]), and measurement error (standard error of measurement and smallest detectable change [SDC]). Structural validity was evaluated through unidimensional confirmatory factor analysis, and construct validity was investigated by a priori hypotheses with other measures. Responsiveness was evaluated by testing a priori hypotheses using data at baseline and at 2-week follow-up. RESULTS: Two hundred fourteen patients (53% males and 47% females) with a mean age of 66.2 years (standard deviation = 7.8 years) were included, of which 193 patients completed the 2-week follow-up for our responsiveness analysis. The RMDQ, ODI, and QBPDS showed sufficient internal consistency (Cronbach alpha of .89, .86, and .94, respectively) and test-retest reliability (ICC[2,1] of 0.85, 0.89, and 0.84, respectively). The SDC for the RMDQ was 6.9, for the ODI was 19.1, and for the QBPDS was 23.6, which are values larger than the minimal important change. None of the measures met all criteria for sufficient structural validity. but the RMDQ and ODI exhibited a partial unidimensional fit. The questionnaires had sufficient construct validity and responsiveness. CONCLUSION: The ODI, QBPDS, and RMDQ have similar measurement properties in older adults with LBP.