Psychosocial functioning before and after surgical treatment for morbid obesity: reliability and validation of the Norwegian version of obesity-related problem scale

Faculty of Health Studies, Sogn og Fjordane University Collage, Førde, Norway
Department of Surgery, Førde Central Hospital, Førde, Norway
Department of Community and Family Medicine, Duke University School of Medicine, Durham, NC, US
Quality of Life Consulting, PLLC, Durham, NC, US
Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
DOI
10.7287/peerj.preprints.900v1
Subject Areas
Nursing, Nutrition, Psychiatry and Psychology, Public Health, Surgery and Surgical Specialties
Keywords
Obesity, obesity surgery, Quality of Life, OP-scale, Psychosocial functioning, Validity, Reliability, Questionnaires
Copyright
© 2015 Aasprang et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Aasprang A, Andersen JR, Våge V, Kolotkin RL, Natvig GK. 2015. Psychosocial functioning before and after surgical treatment for morbid obesity: reliability and validation of the Norwegian version of obesity-related problem scale. PeerJ PrePrints 3:e900v1

Abstract

Background: The aims of this study were to translate the Obesity-Related Problem scale (OP scale) into the Norwegian language and test its reliability, validity and responsiveness in a Norwegian sample. Method: The questionnaire (OP scale) was translated from the original language (Swedish) into Norwegian. Patients completed the questionnaire prior to and one year after sleeve gastrectomy. Internal consistency was evaluated using Cronbach`s α. Floor and ceiling effect were calculated as percentages. Construct validity was tested by correlating the OP-scale with the SF-36 and the Cantril Ladder using the Pearson correlation coefficient. Exploratory factor analysis, using principal component analysis with varimax rotation, was used to test the unidimensionality of the OP scale. Responsiveness was tested by assessing changes in the OP scale from baseline to one year post-surgery using the paired sample t-test. Result: A total of 181 patients (123 women) accepted for bariatric surgery was included in the study. The mean age was 43.1 ± 12.5 years, and mean body mass index (BMI) before surgery was 45 ± 6.9. The mean value of the OP scale at baseline was 63.30 ± 24.43 (severe impairment) and 21.01 ± 20.98 at one year follow-up (mild impairment). Cronbach`s α was high at baseline (0. 91), as well as one year after surgery (0.88). The floor effect was small at baseline and moderate at one year. The ceiling effect was small at baseline and at one year. Exploratory factor analysis showed one factor with a high percent of explained variance (baseline and post-surgery). Correlations between OP scale at baseline, SF-36, Cantril Ladder and BMI were statistically significant and in the predicted direction to support validity of the Norwegian OP scale . After one year correlations between the change in OP scale and the change in SF-36 scores, Cantril Ladder and BMI were also statistically significant, except for the change in the Role Physical-scale. The OP scale showed greater responsiveness than either the SF-36 or Cantril Ladder. Conclusion: These results confirm that the Norwegian version of the OP scale is a valid and reliable instrument for measuring psychosocial functioning in patients with clinically severe obesity.

Author Comment

This is a submission to PeerJ for review.