Volume 14 Supplement 1

2nd Clinical Trials Methodology Conference: Methodology Matters

Open Access

An exploratory and confirmatory analysis of the oxford hip score: generation of subscales assessing self-reported function and pain

  • Kristina Harris1,
  • David Beard1,
  • Jill Dawson1 and
  • Andrew Price1
Trials201314(Suppl 1):P74

https://doi.org/10.1186/1745-6215-14-S1-P74

Published: 29 November 2013

Aims

The aim of this study was to explore dimensionality of the Oxford Hip Score (OHS) and examine if pain and self-reported functioning can be distinguished from the OHS in the form of subscales.

Methods

Secondary data analysis of the UK National Health Service (NHS) audit dataset containing pre-operative OHS scores on 134, 710 patients who were undergoing hip replacement surgery.

Results

The proposed number of factors to extract depended on the method employed. Velicer’s Minimum Average Partial test suggested one factor, the Cattell’s scree test and parallel analysis suggested two factors, and the second eigenvalue of 1.04 also suggested two factors. Exploratory factor analysis demonstrated that the 2-factor OHS had most of the items saliently loading either of the two factors. These factors were named ‘Pain’ and ‘Function’ and their respective subscales were created. Cronbach’s alpha was 0.90 for the 12-item summary scale, 0.85 for the 6-item ‘Function’ subscale, and 0.82 for the 6-item ‘Pain’ subscale. Confirmatory factor analysis demonstrated that the 2 factor model of the OHS had somewhat better fit. However, none of the one factor or two factor models was rejected.

Conclusions

Factor analyses demonstrated that, in addition to the current use a single summary scale, separate information on pain and self-reported function can be extracted from the OHS in a meaningful way, in the form of subscales.

Authors’ Affiliations

(1)
University of Oxford

Copyright

© Harris et al; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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