| dc.description.abstract | Background: Patient reported outcome measures (PROMs) are regularly used in research, and increasingly in clinical practice for individuals with chronic conditions, to gather patients’ perspective on their experience of health. Whereas research applications have focused on the use of aggregate PROMs information, biological rhythms and other intraindividual cycles have potential implications for how patients report on their health using PROMs, and ultimately the scores that are produced, with potentially important implications for the use of PROMs at the individual level. Research on this issue is, however, sparse and results in a lack of understanding of the key concepts, methods and associated phenomena associated with individual cyclical variation in PROMs scores. Aim: The aim of this thesis is to explore the cyclical variation in patient reported outcome measurements (PROMs) in patients with chronic conditions. Specific objectives included: a) the development of a conceptual model for researching cyclical variation of PROMs, b) the elicitation of patient perspectives on cyclical variation in PROMs, and c) the mapping, selection and use of best methods for the statistical modelling of cyclical variation. Method: This thesis comprised of three sequential studies which informed each other to address the aims and objectives of the thesis. A mixed methods scoping review, considering both quantitative and qualitative research, was conducted to map out the knowledge on cyclical variation of patient reported outcome measurements in patients with chronic conditions. Findings from this scoping review informed the development of a conceptual model building up on established outcomes models. A longitudinal mixed methods study was conducted to understand the factors that were important in the cyclical variation of PROMs from the patients’ perspective, to test the concepts within the conceptual model and to refine it. Sixteen individuals recruited with varying combinations of asthma, depression and osteoarthritis and conducted a total of 3 interviews with each participant over a 9-month period, in order to account for seasonal changes. Finally, variation in outcome scores for a range of symptoms (aural fullness, tinnitus, dizziness, and hearing loss) in Meniere’s disease was modelled by applying Fourier transformation using quantitative longitudinal data on Meniere’s symptoms captured across time . Results: The scoping review identified 33 articles which provided empirical evidence for cyclical variation in PROMs, in respiratory, musculoskeletal, mental health and neurological conditions. The hypotheses and findings in the documents were used to develop a conceptual model of cyclical variation of PROMs in chronic conditions which included the following concepts: determinants (biorhythms, timing and type of healthcare interventions), variation in outcomes (health conditions, outcomes, and time-period), a mediator (psychological health status), moderators (individual and environmental factors), and variation in scores (cognition, integration, measurement, recall and interpretation). Patient interviews confirmed both cyclical variations in outcomes as experienced by patients themselves as well as the relevance of the concepts included in the conceptual model and supported the inclusion of additional ones (sleep, partners interpretation of outcomes and salience of recent episodes and/or flare ups). Fourier analysis of the Meniere’s disease data showed that the severity of symptoms was reported differently across a 24-hour period. Individuals reported the morning to be the worst time of the day for hearing loss and dizziness, tinnitus, and aural fullness peaking around 1/2pm. However, all four symptoms presented a decline in symptom severity by the evening. Conclusion: This thesis has laid the theoretical and methodological foundation for future research on the cyclical variation of PROMs in patients with chronic health conditions. It has confirmed its existence for selected conditions based on literature synthesis and a mixed methods study. The new conceptual model developed as part of this work, which identifies key sources of variation and hypothesises pathways that may explain intraindividual variation of PROMs, will facilitate further research. Findings from the, to my best knowledge, first longitudinal mixed methods study eliciting narratives of cyclical variation may benefit from replication in other patients and for other conditions. Finally, Fourier analyses, emerges as the analytical approach of choice to model cyclical variation of PROMs. Potential application of PROMs to monitor the impact of chronic conditions on patient’s health needs to take into account cyclical variation in the selection, administration and interpretation of PROMs scores. | en_GB |
