Validity and reliability testing of the Quality of Life Scale, Swedish version in women with fibromyalgia – statistical analyses

Authors

  • Gunilla M. Liedberg PhD, MSc OT (University Lecturer),

    1. Department of Neuroscience and Locomotion, Section of Occupational Therapy, Faculty of Health Sciences, Linköping University, Linköping, Sweden
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  • Carol S. Burckhardt PhD, RN (Professor of Nursing and Assistant Professor of Medicine Research),

    1. Division of Arthritis and Rheumatic Diseases, Department of Medicine, School of Medicine, Oregon Health Sciences University, Portland, OR, USA
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  • Chris M. Henriksson PhD, MSc OT (Associate Professor)

    1. Department of Neuroscience and Locomotion, Section of Occupational Therapy, Faculty of Health Sciences, Linköping University, Linköping, Sweden
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Gunilla M. Liedberg, INR, Faculty of Health Sciences, Section of Occupational Therapy, University Hospital, Villa Medica, 581 85 Linköping, Sweden.
E-mail: gunilla.liedberg@inr.liu.se

Abstract

One consequence of constant widespread pain is a low quality of life. The purpose of the study was to examine whether the Quality of Life Scale, Swedish version (QOLS-S), regarded as a generic quality-of-life instrument, is a reliable and valid instrument for use in women with fibromyalgia (FM). Women with FM (n = 113) contributed data on the QOLS-S and other standardized instrument at three points in time. Internal consistency reliability estimates ranged from 0.89 to 0.92. Convergent construct validity was indicated by moderate agreement with a global life satisfaction question. Discriminant construct validity was denoted by low correlations with the physical functioning subscale of the SF-36. In a factor analysis three factors emerged: ‘personal and social well-being’, ‘relations with others’ and ‘active participation’. A few of the items have high cross-loadings, and the instrument could be improved by rewording those items to more closely reflect one specific factor. Overall, these results provide evidence that the QOLS-S has acceptable validity and reliability for use in women with FM.

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