| Amsterdam International Forum VIII PRIMARY CARE RESEARCH ON LOW BACK PAIN |
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FP3.2
Title: Minimal clinically important change on outcome measures in patients with non-specific low back pain. Authors and affiliation: van der Roer N1, Ostelo RWJG1,2, Bekkering GE1, van Tulder, MW1, de Vet HCW1. 1 EMGO Institute, VU University Medical Centre, The Netherlands Background and purpose: Minimal clinically important change (MCIC) can provide valuable information for researchers, health care providers and policymakers. The aim of this study was to estimate the MCIC of the pain numerical rating scale (PI-NRS), the Quebec Back Pain Disability Scale (QBPDS) and the Euroqol (EQ), in a large population of patients with low back pain. Methods: Data from a large randomised controlled trial with 442 low back pain patients was used. The MCIC was estimated over a 12 week period and three different methods were used: (1) mean change scores; (2) minimal detectable change; (3) optimal cut-off 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 low back pain patients. The MCIC of the QBPDS was determined between 17.5 to 32.9 points and 8.5 to 24.6 points for (sub)acute and chronic low back pain patients. The MCIC for the EQ ranged from 0.09 to 0.58 in (sub)acute patients and 0.09 to 0.28 in patients with chronic low back pain. In general the MCIC was larger in (sub)acute patients than in chronic patients. Initial scores were of significant influence on the MCIC for all three outcome measures. Discussion: The magnitude of the MCIC depends on the methods used and initial scores. We present a range of MCIC values and advocate the choice of a single MCIC value according to the specific context. Reporting the percentage of patients who have made a MCIC adds to the interpretability of study results. |
