The Oxford Participation and Activities Questionnaire (Ox-PAQ): development of a short form and index measure

Abstract

Background

The Oxford Participation and Activities Questionnaire (Ox-PAQ) is a 23-item patient-reported outcome measure (PROM) theoretically grounded in the World Health Organisation International Classification of Functioning, Disability and Health. Initial validation of the Ox-PAQ identified three domains; routine activities (14 items), emotional well-being (5 items) and social engagement (4 items). The purpose of the analyses reported here were to determine whether an overall index score can be calculated from the measure, and then to determine whether a shorter form measure can replicate results on the index score.

Methods

Two surveys of people with long term conditions were undertaken. In the first study, higher order factor analysis is used to determine that a single index score can be calculated for the Ox-PAQ. Regression analyses are used to determine a sub-set of items selected for the Short Form Ox-PAQ (SF-Ox-PAQ). In the second study, results on the Ox-PAQ Single Index and SF-Ox-PAQ Single Index are compared with results from another generic measure, the EuroQol EQ-5D-5l.

Results

Higher order factor analysis confirmed that a single index score can be created from the Ox-PAQ. Further, linear regression indicated 14 items could reliably and accurately produce this index. The two methods of creating the index were highly correlated (ICC =0.99). The two indices were found to provide almost identical levels of correlation with EQ-5D-5L scores.

Conclusion

Results indicate that the Ox-PAQ can be summed to provide an index score, and, furthermore, a sub set of fourteen items can very closely replicate the results gained from the original parent form.

Keywords:

• activity
• participation
• routine activities
• higher order factor analysis
• summary index

Acknowledgments

We would like to acknowledge the following organisations for their support in recruiting participants for this study: the British Lung Foundation, MND Association, MS Society and Parkinson’s UK. We would also like to acknowledge the continued support and assistance of Dr Mary Baker MBE, Immediate Past President, European Brain Council. Finally, we wish to thank the participants who so readily gave their time to take part in the study. Development and validation of the Ox-PAQ were funded by the European Brain Council.

Abbreviations

COPD, chronic obstructive pulmonary disease; EQ-5D-5L, Euroqol five dimension five level questionnaire; ICC, intra-class correlation ceofficient; KMO, Kaiser-Meyer-Olkin; MND, Motor Neurone Disease; MS, multiple sclerosis; Ox-PAQ, Oxford Participation and Activities Questionnaire; PD, Parkinson’s disease; SF-Ox-PAQ, Short-Form Oxford Participation and Activities Questionnaire.

Availability of data and material

The datasets analysed for the current study are available from the corresponding author on reasonable request.

Ethics approval and consent to participate

Ethical approval was granted by the Medical Sciences Inter Divisional Research Ethics Committee of the University of Oxford (refs: R44281/RE001 and MSD-IDREC-C1-2014-089). Informed consent to participate was obtained from all participants.

Author contributions

All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

All authors are developers of the Ox-PAQ and will receive royalties from its use in commercial contexts. All authors have also undertaken consultancy work for Oxford University Innovation, the copyright holder of the Ox-PAQ. The authors report no other conflicts of interest in this work.