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T. Benz1,2,3,4, S. Lehmann1, A. Elfering3, P. Sandor1, F. Angst1
1RehaClinic, Research Department, Bad Zurzach, Switzerland, 2Zurich University of Applied Sciences, Institute of Physiotherapy, Winterthur, Switzerland, 3University of Bern, Institute of Psychology, Bern, Switzerland, 4University of Bern, Graduate School for Health Sciences, Bern, Switzerland
Background: Multidimensional chronic low back pain (CLBP) syndrome affects physical activity and function, health-related quality-of-life and employment state. In the evaluation of the efficacy and effectiveness of CLBP treatments and under the aspect of the biopsychosocial model, the simultaneous assessment of patients' HRQoL and their physical, emotional, and social functioning is highly recommended in clinical practice and for scientific evaluation purposes.
Purpose: The aim of this study was to examine how the complexity of the syndrome can be comprehended and the validity of single measurement scales in the multidimensional and comprehensive assessment in patients with CLBP before and after a standardized 4-week interdisciplinary pain program.
Methods: This prospective cohort study assessed 177 patients by the Short Form 36 (SF-36), the Multidimensional Pain Inventory (MPI), the Symptom Checklist-90-Revised (SCL-90-R), and the Oswestry Disability Index (ODI), and by 2 functional performance tests, the Back Performance Scale (BPS) and the 6-Minute Walking Distance (6MWD). Comprehensiveness and overlap of the constructs were cross-sectionally and longitudinally quantified by bivariate correlations, explorative factor analysis, and effect sizes (ES).
Results: Patients included in this study were of 48.0 years (+/-12.7) and 59.3% female. Correlations of baseline scores ranged from r=–0.01 (BPS with MPI Life control) to r=0.76 (SF-36 Mental health with MPI Negative mood). SF-36 Physical functioning correlated highest with functional performance tests (r=0.58 BPS, 0.67 6MWD) and ODI (0.56). Correlations of change scores (difference of follow-up – baseline score) were consistent but weaker. Factor analysis revealed 2 factors: psychosocial and pain & function (totally explained variance 44.0–60.9%). In all 3 analyses, psychosocial factors loaded strongest (up to 0.89 SCL-90-R) on the first factor, covering 2/3 of the explained variance. Pain and function(ing) loaded stronger on the second factor (up to 0.81 SF-36 Physical functioning). All scales showed improvements by ES ranging from 0.16–0.67.
Conclusion(s): High levels of explained variance in the factor analysis and improvements on all used scales illustrated the complexity of the CLBP syndrome comprising much more dimensions of health and quality of life than only back related function. Some of the physical scales of the pain-specific MPI and ODI showed moderate to high construct overlap as well as the affective health scales of the SF-36, the MPI, and the SCL-90-R. The broad spectrum of measured constructs was proven by the fact that many scales showed only partial convergence in the same domain.
Implications: The selected set of individually validated measurement scales used to assess the complex, multidimensional CLBP syndrome appeared to provide comprehensive coverage and assessment of the condition, especially the mental health and psychosocial aspects. Our findings underline that the CLBP syndrome comprises many more dimensions of health and quality of life than just back-related functioning.
Funding, acknowledgements: There are no sources of funding to declare.
Keywords: Chronic Low Back Pain, Multidimensional assessment and Validity, Patient-reported and Performance-based outcome measurements
Topic: Disability & rehabilitation
Did this work require ethics approval? Yes
Institution: ethics committee of Aarau, Canton Aargau, Switzerland
Committee: ethics committee of Aarau, Canton Aargau, Switzerland
Ethics number: EK AG 2008/026
All authors, affiliations and abstracts have been published as submitted.
