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Evaluating quality of life measurement in psoriasis and the development of new solutions to improve the use of patient-reported outcomes

Ali, Faraz Mahmood 2021. Evaluating quality of life measurement in psoriasis and the development of new solutions to improve the use of patient-reported outcomes. PhD Thesis, Cardiff University.
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Abstract

Psoriasis has considerable impact on the quality of life (QoL) not only of patients but also of their relatives. This impact is as important to consider as clinical parameters in the management of psoriasis. This thesis aims to evaluate current practices in QoL measurement and devise new solutions to improve these processes, to benefit patients, clinicians and policy makers. The systematic review describing data from 100 psoriasis randomised controlled trials (33 topical, 18 systemic small molecules, 39 biologics and 19 other interventions) in 33,215 subjects highlights that QoL assessment is integral to the assessment of new therapies and to the management of psoriasis. Amongst a variety of generic and disease-specific measures, the Dermatology Life Quality Index (DLQI) is the most commonly utilised QoL tool, though there is heterogeneity in its reporting and analysis. The Minimal Important Clinical Difference (MCID) is an essential baseline in determining treatment efficacy, particularly across measures, but remains grossly under-utilised. This thesis proposes a novel concept of ‘multiple-MCID’, as well as recommendations on QoL reporting. In order to address some of these identified recommendations, an electronic version of the DLQI has been validated for the first time using International Society for Pharmacoeconomics and Outcomes Research (ISPOR) guidelines (n=104). The electronic version was scored equivalently to the paper counterpart, was preferred by majority of patients (76%) and provided advantages such as costefficiency, quicker completion times and more accurate data analysis. The electronic Psoriasis Area Severity Index (PASI) was also validated demonstrating reduced inter-rater variability. Electronic use of these measures would help standardise QoL measurement and propel psoriasis management into the digital era. Whilst QoL information is invaluable for clinical decision-making, generic measures are utilised by healthcare policy-makers for resource allocation. This is not always representative of the impact revealed by disease-specific QoL measures. In order to solve this dilemma, the DLQI was mapped to EQ-5D to generate utility values using ordinal logistic regression (OLR) from a dataset of 4,010 patients. This sample size was large enough to allow it to be split in half to perform external and internal validity. Where previous methods have failed, the OLR mapping method successfully allowed the conversion of DLQI scores to utility values for large cohorts of patients, using split half validation and Monte Carlo Simulation. This has the potential to be very useful in economic appraisals of any skin disease, including psoriasis. By standardising QoL measurement, validating its electronic data capture and translating this information into meaningful healthy utility information, it is hoped this work further consolidates the central role of QoL assessment in psoriasis.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Medicine
Date of First Compliant Deposit: 23 April 2021
Last Modified: 06 May 2021 12:53
URI: http://orca.cardiff.ac.uk/id/eprint/140744

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