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Title: Design issues and challenges in clinical trials with a surgical and non-surgical comparison
Author: Davies, Loretta
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2019
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Conducting surgical trials is essential to establish evidence based practice and inform health policy, particularly in the face of economic pressures. Randomised controlled trials (RCT) evaluating surgical interventions can be difficult to design and conduct, especially when including a non-surgical comparison. Only around half of initiated surgical trials reach their recruitment target, and failure to recruit is cited as the most frequent reason for premature closure of surgical RCTs. The aim of the thesis was to gain a greater understanding of the main methodological challenges to the design and conduct of trials that directly compare surgical and non-surgical interventions, explore potential solutions, and provide guidance for use in future studies. The work contained in the thesis purposefully used several different methodologies; a systematic review, case study, qualitative evidence synthesis and two qualitative interview studies. This approach provided insight from different perspectives in order to more fully understand the challenges involved in this type of trial, and therefore contribute to the design of future trials. Several methodological challenges were identified in these types of trials related to; difficulty implementing blinding, recruitment difficulties, complexity of intervention content and delivery, imbalance in timing of follow-up, non-compliance with treatment allocation, and differential loss to follow-up. The dichotomy between several aspects of the surgical and non-surgical interventions, for example, level of invasiveness, risk, and perceived mechanism of effect, were seen to contribute to strong preferences of both patients and clinicians, making recruitment particularly challenging. The potential benefits of undertaking pre-trial qualitative research to identify potential issues of patients' and clinicians' treatment preferences in these types of trials, was also identified. Several methodological issues were identified in this thesis that have the potential to impact on the design, conduct and analysis of these types of trials. If not adequately addressed, these issues may introduce significant bias and threaten the viability of the trial, and also the validity of the results. Consideration of these specific challenges should be made in the planning and design of future studies to optimise trial conduct.
Supervisor: Cook, Jonathan ; Price, Andrew ; Beard, David ; Toye, Francine Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available