Psoriatic Arthritis and Psoriasis

265 Pages·2013·13.98 MB·English

Psoriatic Arthritis and Psoriasis: The Role and
Impact of Psychosocial Factors
Catherine Anne Aitken
A thesis submitted in partial fulfilment of the requirements of Liverpool John
Moores University for the degree of Doctor of Philosophy
March 2011
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No portion ofthe work referred to in this Research Dissertation has been submitted in support
of an application for another degree or qualification of this or any other university or institute
of learning.
This thesis was supervised by a member of academic staff, but it is essentially the work of the
author. Views expressed are those of the author and are not necessarily those of any member
of the Faculty of Science.
Copyright in text of this research thesis rests with the author. The ownership of any
intellectual property, rights, which may be described in this thesis, is vested in the Liverpool
John Moores University and may not be made available for use to any third parties without the
written permission of the university.
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Acknowledgements
I would like to express my sincere thanks to a considerable number of people, without whom
this thesis would not have been possible. Firstly to Dr. Helen Poole, the Director of Studies,
whose guidance and infmite patience have been inexhaustible.
My appreciation also goes to Terry Adams and Dr. Anne Whyte for being part of the
supervision team.
Thanks must also go to Professor Robert Moots and Dr. Marina Anderson and the team at the
Academic Rheumatology Department at University Hospital Aintree, NHS Foundation Trust,
Liverpool, who have supported me with this research and been a constant source of advice and
humour.
Abby, Beth, Lottie and Russ - who at different times have shared the PhD experience with
me.
Special thanks to my Wirral NHS Public Health colleagues in the Wirral Working 4 Health
team - along with their tea-making, their humour has truly known no bounds!
And finally, Bee, who never doubted - not once.
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Contents
Acknow ledgements III
List of Figures VI
List of Tables VII
Abstract IX
Chapter 1: Introduction to the thesis I
Chapter 2: Literature review 4
Chapter 3: Rationale for Methodology Study 1 37
Chapter 4: Study I (Qualitative) 41
Chapter 5: Review of Measures 67
Chapter 6: Study 2 (Quantitative) 98
Chapter 7: Discussion 138
References 176
Appendix 1: Audio consent form
Appendix 2: Participant invitation letter & consent form
Appendix 3: Participant Information sheet
Appendix 4: Questionnaire Booklet
Appendix 5: Interview Schedule
Appendix 6: Example of theme table
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Contents (Contd.)
Appendix 7: Example of interview transcription
Appendix 8: Ethics and R&D approval
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List of Figures
Figure 1: Joint swelling and deformity of hands in PsA patient 9
Figure 2: Severe deformity of hands in PsA patient 10
Figure 3: Arthritis mutilans 10
Figure 4: Plaque psoriasis 13
Figure 5: Inverse psoriasis 13
Figure 6: Erythrodermic psoriasis 13
Figure 7: Guttate psoriasis 13
Figure 8: Pustular psoriasis 13
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List of Tables
Table 4.1 Characteristics of participants who were interviewed 42
Table 4.2 Superordinate category of Pain 46
Table 4.3 Themes supporting development of five superordinate themes 47
Table 5.1 Summary of function & disability measures 77
Table 5.2 Summary of pain measures 80
Table 5.3 Summary of coping measures 83
Table 5.4 Summary of fatigue measures 85
Table 5.5 Summary of emotions measures 88
Table 5.6 Summary of measures for psoriasis 91
Table 6.1 Postal questionnaire response rates 101
Table 6.2 Useable questionnaires following Normality tests 101
Table 6.3 SF-36 Norms for 3 different populations 103
Table 6.4 Gender, age & marital status descriptives for 'Recruitment Group' 112
Table 6.5 Disease duration & treatment for 'Recruitment Group' 113
Table 6.6 Employments & qualifications for 'Recruitment Group' 114
Table 6.7 Means (SD) for all measures for total sample 115
Table 6.8 Means (SD) for all measures for 'Recruitment Group' 116
Table 6.9 Means (SD) for SF-36 subscales for 'Recruitment Group' 116
Table 6.10 Gender, age & marital status for 'Disease Group' 119
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List of Tables (contd)
Table 6.11 Employment & qualifications for 'Disease Group' 120
Table 6.12 Disease duration & treatment for 'Disease Group' 121
Table 6.13 Means (SD) & t-test results for all measures for 'Disease Group' 122
Table 6.14 SF-36 subscales Means (SD) for 'Disease Group' 123
Table 6.15 J-Sample t-tests between PsA +Psoriasis Group & known population 124
Table 6.16 J-Sample t-tests between Psoriasis Group & known population 126
Table 6.17 Correlations matrix for total sample 130
Table 6.18 Correlations matrix for Group with Psoriasis +PsA 131
Table 6.19 Correlations matrix for Psoriasis Group 132
Table 6.20 Correlations comparison matrix for 'Disease Groups' 133
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Abstract
This thesis is concerned with the psychosocial impact of psoriatic arthritis (PsA) - an
inflammatory arthritis associated with psoriasis.
Although an extensive literature exists on the nature and impact of psoriasis, little is known
about the effect that psoriatic arthritis can have on an individual, and the bearing it may have
on their quality of life. In order to address this gap in the literature, this study utilised a mixed
methods research design, employing a qualitative study with semi-structured interviews,
followed by a quantitative, cross-sectional postal survey.
In the qualitative study, interviews were conducted with ten people living with psoriatic
arthritis. Analysis of the data, using Interpretative Phenomenological Approach (JPA; Smith,
2003) resulted in five emerging themes; pain, functionality (including fatigue), emotions
(including depression), coping and treatment experience/management.
The quantitative study used a postal survey to measure the variables of interest and explore the
associations between them. Survey respondents consisted of a sample (n = 313) drawn from
The Psoriasis Association membership and also 44 from a hospital rheumatology clinic. AA
participants completed a piloted questionnaire containing questions about their demographic
characteristics and validated measures of quality of life.
Analysis confirmed that the group with PsA fared less well on all measures of quality of life,
than those with just psoriasis. Correlations identified highly significant relationships between
most study variables, however of note were the relationships between fatigue and current pain
(r = .547) and depression (r = .670). Within the Psoriasis Group correlations of interest
included those between anxiety and social functioning (r = -.606) and DLQI and social
functioning (r = -.546). Comparison of the correlations identified 18 that were significantly
different between the groups. Of these, relationships between physical functioning, pain,
fatigue and self efficacy were of particular interest, whilst in the psoriasis group the
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