Study Design. Cohort study.
Objectives. To estimate the Minimal Clinically Important Change (MCIC) of the pain intensity numerical rating scale (PI-NRS), the Quebec Back Pain Disability Scale (QBPDS), and the Euroqol (EQ) in patients with low back pain.
Summary of Background Data. MCIC can provide valuable information for researchers, healthcare providers, and policymakers.
Methods. Data from a randomized controlled trial with 442 patients with low back pain were used. The MCIC was estimated over a 12-week period, and three different methods were used: 1) mean change scores, 2) minimal detectable change, and 3) optimal cutoff point in receiver operant curves. The global perceived effect scale (GPE) was used as an external criterion. The effect of initial scores on the MCIC was also assessed.
Results. The MCIC of the PI-NRS ranged from 3.5 to 4.7 points in (sub)acute patients and 2.5 to 4.5 points in chronic patients with low back pain. The MCIC of the QBPDS was estimated between 17.5 to 32.9 points and 8.5 to 24.6 points for (sub)acute and chronic patients with low back pain. The MCIC for the EQ ranged from 0.07 to 0.58 in (sub)acute patients and 0.09 to 0.28 in patients with chronic low back pain.
Conclusion. Reporting the percentage of patients who have made a MCIC adds to the interpretability of study results. We present a range of MCIC values and advocate the choice of a single MCIC value according to the specific context.
The Minimal Clinically Important Change (MCIC) for the pain intensity numerical rating scale (PI-NRS), the Quebec Back Pain Disability Scale (QBPDS), and the Euroqol (EQ) was estimated. The magnitude of the MCIC depends on the methods used and initial scores. The choice for a single MCIC value should be made according to the specific context.
From the *Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, the Netherlands; †Hogeschool van Amsterdam, University for Professional Education, Amsterdam, the Netherlands; ‡Department of Social Medicine, University of Bristol, England; and §Department of Nutrition & Health, Faculty of Earth and Life Sciences, VU University, Amsterdam, the Netherlands.
Acknowledgment date: September 23, 2004. First revision date: December 22, 2004. Acceptance date: March 14, 2005.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Nicole van der Roer, Institute for Research in Extramural Medicine, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; E-mail: N.firstname.lastname@example.org