Cohort study.
To assess the responsiveness and minimal clinically important change (MCIC) of 6 commonly-used performance tests (5-minute walking, 50-ft walking, sit-to-stand, 1 minute stair climbing, loaded forward reach, Progressive Isoinertial Lifting Evaluation).
Performance tests are used to evaluate physical function in people with low back pain. Little is known about their clinimetric properties.
Performance tests were administered in people with chronic nonspecific low back pain (n = 198) before and after 10 weeks of treatment. At 10 weeks, the global perceived effect scale was used to determine if participants judged themselves as worsened, unchanged, or improved. The mean change scores for each performance test were calculated. A performance test was considered responsive if the area under the receiver operating characteristic curve (AUC) was equal to or greater than 0.70. We used 2 methods to evaluate MCIC: the optimal cut-off point based on the receiver operating characteristic curve, which takes into account both sensitivity and specificity, and the minimal detectable change for improvement, which considers test specificity only.
In general, the mean change scores were the smallest in participants who judged themselves worsened and largest in those reporting to be improved. Sit-to-stand (AUC = 0.75) and stair climbing (AUC = 0.72) were the only performance tests that showed adequate responsiveness. For sit-to-stand, the MCIC ranged from 4.1 to 9.8 seconds (19%–45% of the mean baseline score). For stair climbing, the MCIC ranged from 14.5 to 23.9 steps (19%–31% of the mean baseline score).
Only 2 of the 6 performance tests were responsive. Both had acceptable MCIC values. Developing individualized performance tests might partly overcome the general lack of responsiveness of performance tests. Future research should focus on the clinimetric testing of performance tests in subgroups.
Responsiveness and minimal clinical important change were calculated for 6 often used performance tests designed to evaluate treatment in chronic low back pain. Only 2 of 6 performance tests showed to be responsive. These 2 had acceptable minimal clinical important changes values.
From the *Faculty of Health Science, University of Linköping, Linköping, Sweden; †The George Institute for International Health, University of Sydney, Sydney, Australia; ‡Adelante Zorggroep, Hoensbroek, The Netherlands; and §Department of Rehabilitation Medicine, CAPHRI, Maastricht University, Maastricht, The Netherlands.
Acknowledgment date: October 22, 2009. Revision date: November 28, 2009. Acceptance date: November 29, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Federal 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.
Supported by Zorgonderzoek Nederland/Medische Wetenschappen (ZonMw) grant number 014–32–007. Funded by the National Health and Medical Research Council, Australia (to L.C.C.).
Address correspondence and reprint requests to Rob J. E. M. Smeets, MD, PhD, Adelante Zorggroep, PO Box 88, 6430 AB Hoensbroek, The Netherlands; E-mail: r.smeets@adelante-zorggroep.nl
