Postgraduate Research Fellowship Report - Julia Hirschwald
Development of a Core Outcome Set for Dysphagia Interventions in Parkinson’s disease: the COS-DIP study
Swallowing difficulties (dysphagia) are a frequent and clinically relevant symptom in people with Parkinson’s disease (PD). Dysphagia clinicians should base their decisions for the safest and most effective dysphagia intervention for people with PD on the available evidence. However, transferring the outcomes of clinical trials into clinical benefits for these patients is oftentimes quite challenging. This may be due to missing relevant outcomes to patients and decision makers (e.g., as clinicians amongst others), insufficient or no definition of outcomes, missing data in the study reports, publication or reporting bias, lack of reporting of adverse events and missing data on the long-term effectiveness of the intervention.
In a scoping review on swallowing outcomes in dysphagia interventions in PD we identified a high variability of outcomes applied in clinical trials (Hirschwald et al., 2023). Furthermore, their definitions, method of measurement and timepoints of measurement varied across included studies. Additionally, lack of information on outcomes, omitted outcomes (e.g., stated in the methods section to be measured but not reported in the results section of the study) and no inclusion of possible additional relevant outcomes (e.g., parameters associated with cough, nutrition, hydration) were found to decrease the quality of clinical trials on dysphagia in PD.
Thus, researchers are currently measuring different outcomes at different timepoints with different outcome measurement instruments. Additionally, patients, who are supposed to benefit from the treatment, are traditionally not consulted on what outcomes matter to them most. Therefore, the decision of what to measure in a clinical trial usually stays within the research team which oftentimes does not comprise patient and public involvement.
This heterogeneity of clinical trials and lack of inclusion of key stakeholders leads up to research waste. We have these possibly effective dysphagia interventions, but if we cannot synthesise and compare the study results in systematic reviews and meta-analyses, we are unable to establish a sufficient evidence base for dysphagia interventions in PD and ultimately, we cannot provide effective treatment to patients. Thus, we are wasting millions of dollars and are adding to ongoing research waste.
A solution to this challenge is the development and use of an agreed standardised set of outcomes that should be measured and reported as a minimum in all clinical trials. This is called a Core Outcome Set (COS). As part of my PhD project, the aim is to develop a Core Outcome Set for Dysphagia Interventions in Parkinson’s disease (COS-DIP) devised by key stakeholders including healthcare professionals, researchers, and patients.
This means, that in every clinical trial on a dysphagia intervention in PD these core outcomes will be measured so that every randomised controlled trial (RCT) can go into a meta-analysis. Ultimately, this will reduce the amount of research waste and improve the evidence base for dysphagia interventions in PD. More information on this project can be found on our website.
To do this, we established a study steering committee that will lead and conduct the development of the COS-DIP. It is a multidisciplinary, international group and comprises experts from the field of speech and language therapy, COS methodology, neurology, clinical trials in dysphagia in PD and a public research partner with PD. The stages of the COS development comprise the following:
- A scoping review to identify what outcomes have been used in clinical trials on dysphagia in PD (Hirschwald et al., 2023)
- An online survey and thereafter focus groups with people living with dysphagia in PD, their family caregivers and family members to find out what outcomes matter to them most when deciding if a swallowing treatment works
- Three consecutive, online Delphi surveys with healthcare professionals, researchers, patients, their family caregivers and family members to identify the most important outcomes
- Two online consensus meetings to agree on all core outcomes, definitions, methods and timepoints of measurement
I was delighted to present the results of stage 1 at the annual conference of the North American Dysphagia Research Society (DRS) in San Francisco in March 2023. A very nice surprise was the award for 2nd best poster presentation.
A year later, I got the chance to present the results of the focus groups as part of stage 2 at DRS. This time it took place in beautiful San Juan, Puerto Rico.
For stage 3, the online Delphi survey, we used the DelphiManager platform which is specifically designed for conducting Delphi surveys to reach consensus on core outcomes. The cost of using this platform is approximately €1,200. Without the TRiSS Postgraduate Research Fellowship we would not have been able to use this immensely helpful platform. So, a big thank you to TRiSS for awarding us this fellowship.
All the main stages of the COS-DIP project have now been completed and we are currently writing up the results. Once again, I would like to thank the TRiSS Research Fellowship Committee for giving us the opportunity to use this specialised platform to conduct the online Delphi survey.