Musculoskeletal pain illness perceptions: Factor structure of the Illness Perceptions Questionnaire-Revised

Abstract

Background: The Revised Illness Perceptions Questionnaire (IPQ-R) is commonly used to measure illness perceptions. We tested whether the structure of the IPQ-R was appropriate for use with primary care musculoskeletal pain patients.

Methods: Confirmatory (C) and exploratory (E) factor analyses (FA) were used to test whether the structure of the IPQ-R was supported for patients with knee pain (n = 393), hand pain (n = 2113) and back pain (n = 1591). CFA was used to test whether the timeline acute/chronic, timeline cyclical, consequences, personal control, treatment control, illness coherence and emotional representation dimensions of the IPQ-R were distinct; EFA was used to explore potential structure for patients’ views on the cause of their condition.

Results: Goodness-of-fit indices for the CFA were below our criteria for good model fit. Removal of six items from the model improved model fit, but our criteria for good model fit was still not achieved. An interpretable factor solution could not be determined for the causal items on the questionnaire.

Conclusions: Our data show limited evidence that the seven dimensions of the IPQ-R are distinct. A clear structure for the causal items was not determined. Further work is needed to develop the IPQ-R for use with primary care musculoskeletal pain patients.

Keywords:

• illness perceptions
• musculoskeletal pain
• factor analysis
• IPQ-R
• IPQ
• questionnaire

Acknowledgements

The three studies included in this analysis were supported by Arthritis Research UK, the Medical Research Council and the North Staffordshire Primary Care Research Consortium in the UK. The authors would like to thank the Principal Investigators for use of the data, the administrative and health informatics staff and the three study teams at the Arthritis Research UK Primary Care Centre, Keele University. We also thank the Keele General Practice Partnership, the regional research network of physiotherapists and participating clinicians and patients. We are also grateful to Professor Elaine Hay, Dr Elaine Thomas and Professor Krysia Dziedzic for helpful comments on the manuscript.