Abstract
OBJECTIVES: The present study aimed to investigate the responsiveness of the Persian version of the Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMDQ), and Quebec Back Pain Disability Scale (QBPDS) and detect minimal clinically important changes (MCICs) of these questionnaires in people with lumbar disc herniation. METHODS: Ninety-two patients with lumbar herniated disc completed the Persianversion of the ODI, RMDQ, and QBPDS before and after the physiotherapy intervention. Additionally, they completed a global rating of change scale after the final physiotherapy session to give an account of non-improved and improved outcomes. The responsiveness of these three disability questionnaires was represented by Receiver Operating Characteristic (ROC) and correlation analyses. The MCIC was defined as the best cut-off when sensitivity and specificity were optimally balanced. RESULTS: Area under the ROC curves are in the acceptable range for ODI and QBPDS (0.78 and 0.70, respectively). Moreover, ODI, RMDQ, and QBPDS have significant positive fair to moderate correlation with the external anchor (P<0.001). The MCIC values for ODI, RMDQ, and QBPDS were 13, 5.5, and 14.5 points, respectively. CONCLUSION: Our results revealed that the ODI and QBPDS questionnaires have adequate responsiveness to detect improvements in the functional status of lumbar herniated disc patients following a physiotherapy treatment. Therefore, the ODI and QBPDS seem to be superior to the RMDQ for use in randomized clinical trials and clinical settings in patients with herniated lumbar discs. The MCIC scores of 13 and 14.5 obtained for the ODI and QBPDS can help to identify important changes in the clinical status of an individual patient and treatment efficacy.