Heterogeneity in outcome measures in clinical interventional trials cause a vast amount of research waste. Endpoints of studies in what they set out to measure to judge efficacy of one treatment vs another, i.e. outcome measures, can vary hugely, making it difficult for these studies to be compared and contrasted in larger scale analysis. This leads to perfectly well-designed studies not being incorporated into systematic reviews due to the inconsistency in outcome measures. The variability in outcome measures chosen by researchers can be explained by a number of reasons. A lack of consensus of what the best outcome measures are, can sometimes be the cause. Other causes are slightly more sinister, with researchers cherry picking certain outcome measures which bolster the significance of their findings. This is known as outcome reporting bias. This variability of outcome measures, or lack of consensus of a number of key outcome measures within a particular clinical field, has become a recognised problem in research. This conundrum also affects the research in pleural medicine and pleural interventional trials with a particular lack of patient centred outcome measures. This study aims to develop a set of core outcome measures to be used by pleural interventional trials, as a bare minimum, in order to tackle this problem. Achieving a consensus on a minimum set of outcome measures deemed to core by relevant stakeholders to a particular field, will reduce this variability which causes issues to synthesis of reliable evidence from large scale analysis.
A long list of outcome measures was constructed through a scoping review of the literature, complemented by thematic analysis of semi-structured interviews with key stakeholders. This long list was streamlined in a meeting with four independent reviewers and entered into a modified two stage Delphi process. The Delphi process included both patients and practitioners scoring each included outcome measure on a 9-point scale. Participants were given an opportunity to advise on the list of outcome measures enrolled into the Delphi, ensuring it was an iterative process.
The synthesis of a ‘long list’ of outcomes elicited 9 outcome measures, entered into a Delphi process with a total of 78 participants. The Delphi process refined the long list into a core outcome set, consisting of 4 outcome measures. The Delphi process is a well-known consensus forming process used in the literature.
An all-encompassing core outcome set was developed, tailored to the key stakeholders pertaining to pleural interventions. The aim is for this core outcome set to be incorporated as a minimum to relevant research projects of the future within pleural interventional research and will be a step towards the standardisation of outcome measures, allowing for meaningful synthesis of evidence from the comparison and analysis of independent studies.
Further work must be done to assess the uptake and efficacy of these outcome measures.