Michael Maia Schlüssel1, Marianna Pasqua2, Alessandro Gallo3
1Senior Medical Statistician, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, UK
2Nutritionist and Editorial Project Manager, Springer Healthcare Italia
3General Manager, Springer Healthcare Italia
Most of the nutritional studies conducted so far have been observational, making it difficult to establish a causal relationship with specific factors that may contribute to the development or prevention of chronic diseases. Since we consume complex foods and not just individual nutrients, and even though there are many studies in the literature on the function of specific foods, the results are often conflicting. It is therefore difficult to know which research to believe when it comes to nutritional interventions.
How can we explain some of the uncertain results from clinical trials in the sugar industry, where for years the blame has been focused mainly on fats?
In 2018, M. Schlϋssel started a project to produce a development of the Consolidated Standards of Reporting Trials (CONSORT) statement to the nutritional field, which favors completeness, clarity, and transparency in scientific publications. The CONSORT-Nut will represent a valuable aid in such an ambiguous and confusing context.
What inspired you to develop a CONSORT guideline specifically for the nutrition field?
In 2008, when I was doing my DPhil in Nutrition Sciences, I did a literature review on a specific topic of nutrition during pregnancy. I realized that because the publications were so heterogeneous regarding the information provided about the research methods they were describing, it was impossible to compare the studies. This was, at the same time, puzzling and frustrating.
Fast forward 10 years, I had joined the EQUATOR Network and couldn’t find key information in publications describing studies of nutritional interventions so many times that I felt something needed to be done.
I approached the late Professor Doug Altman, founder of the EQUATOR Network and one of the CONSORT Statement developers, to ask what he thought about the reporting quality in the field of nutrition. He had a similar view to mine regarding the literature in the field, and thought a CONSORT development for nutritional interventions was not only a good idea but a long overdue work.
Which kind of potential bias is most frequently taking place in the field of RCTs in nutrition?
This is a difficult question to answer – and a good one for a research project, thanks! Nutrition patterns and dietary intake are really difficult to assess, which might lead to measurement error. I think this is the main source of bias researchers in the field face when conducting their studies, but that hypothesis needs supporting evidence.
Imagine you are conducting a study to test the effect of increasing the consumption of a given food on overall health or quality of life, for example. Often, researchers forget that when people opt to consume one particular food, they are also necessarily opting for not consuming others. For example, when you eat rice, you usually use it to replace potatoes, or pasta, or bread, or any other kind of food alike, in the meal you prepared.
So, apart from measuring the participants’ consumption, a careful researcher must also consider what they are NOT consuming. This is essential to hypothesise whether the observed effect is given by the consumption of the food of interest, the lack of consumption of the food(s) it is replacing, or both. And that is something pretty difficult to measure.
What do you believe are the most important components of a high-quality randomized controlled trial in the nutrition field?
The most important components in any RCT are those required to be reported in the CONSORT checklist. There is no escape from that. That’s why the checklist is said to be a list of the minimum information authors should report, so anyone reading their papers can understand what was done, critically appraise the findings, and repeat the experiment if needed.
What we set out to do, is to explore which of these items are usually poorly reported in the field of nutrition, why, and determine whether any sort of “tailoring” in the reporting recommendations could aid authors in the reporting of nutritional intervention studies.
We also want to investigate if any additional items, specific to our field, should be added to the checklist. But for the time being, I’d say that adhering to the CONSORT recommendations ensures you provide readers with the minimum amount of information needed about a nutrition RCT.
While there is a clear need to standardize how clinical trials in nutrition are implemented, which direct implications would there be, once the CONSORT NUT guidelines are implemented, as opposed to the current status quo?
We don’t fully know that yet – we aim to fill the current gaps, whatever those may be. Identifying these gaps is one important part of our research programme. Then, we will go further, and one of the things that makes our project so unique is the fact that the decision about what CONSORT-NUT will look like won’t be made only by the researchers developing it. We want the whole community of nutrition RCTs stakeholders to join and have their say.
It might be that, in the end, we determine that the problem is not lack of guidance. In this case, we would produce materials on how to use the existing guidance, focusing on the different types of nutrition interventions being currently investigated, for example.
It might be that we realize that while some interventions require more tailored reporting guidance (for example, nutritional education), others are so similar to those studied in drug trials (for example, supplementation) that the standard CONSORT Statement is sufficient to provide guidance to the authors of such studies.
How did you go about creating this extension to the CONSORT guidelines? What was your process?
In brief, we screened the literature to identify what types of nutritional interventions have been studied in the past 10 years. Then, we appraised the reporting completeness of the publications describing these studies. We are currently compiling the evidence gathered with these literature reviews. The next step, as mentioned above, is to conduct surveys with stakeholders to hear their opinions on our findings and beyond (for example, whether they think we might have missed something). We will then put all the evidence together and pilot the recommendations with researchers in the area of nutrition. When we realize the recommendations are satisfactory, written in accessible language to aid both early career and most senior researchers, we will publish them together with real studies examples of good reporting for each item in the checklists.
A detailed protocol of our research programme is freely available here: https://osf.io/956p3
What are some of the unique challenges that researchers in the nutrition field face when conducting randomized controlled trials?
Again, I am not aware of any research that tried to answer this specific question, but I think cultural, religious, and socio-economical differences may be the main boundaries when trying to test new nutritional interventions, particularly if you need these interventions to be standardised across different populations.
At the end of the day, researchers are trying to improve population and patients’ health and quality of life. This can only be achieved if nutritional interventions are proven to work on a large scale. So, adherence in obviously key.
How does the CONSORT NUT address these challenges?
CONSORT-NUT aims to increase transparency and completeness in the reporting of nutrition RCTs. Clinical practice and nutritional guidelines only change when there is high-quality evidence that an intervention works or works better than the current practice. The evidence quality can only be appraised properly, if studies are well reported.
Also, interventions can only be implemented if they are clearly described. In this sense, CONSORT-NUT will not eliminate the methodological challenges of nutritional intervention studies but pave the way to address them.
How do you envision CONSORT NUT being used by researchers in the nutrition field?
Ideally, like for all other reporting guidelines, CONSORT-NUT will be used when researchers are planning their study. This would ensure all key points are considered early on and well-thought through the study conduct, with a clear impact later when the time comes to report what was done. Writing the papers should then be easy-peasy, and the same goes for any guidelines or policy recommendations arising from these well written publications.
Can you describe any specific feedback or suggestions you received during the development of this guideline?
We are now finishing the background work, which consists in critically appraising the literature to identify the main reporting limitations in the area of nutrition interventions research. The next step is to start gathering feedback on these findings from the widest possible range of stakeholders. So, there isn’t much to share regarding feedback yet.
However, I always like to remember the encouragement Doug Altman gave me from the beginning. We both knew this wouldn’t be an easy task to accomplish, but were as much certain that it is one worth pursuing.
Are there any limitations to this extension that users should be aware of?
We will report on any limitations transparently when publishing the results of this project. All we can say now is that while CONSORT-NUT will give you all you need to report a fantastic RCT, you’ll still need to start with a blank page and type all the information in. We’ve got your back though!
Do you have any plans to update or revise this extension in the future? If so, what changes do you anticipate making?
Part of our research programme is to monitor the uptake and adherence to CONSORT-NUT, as well as explore whether updates are needed, either due to methodological advances in the field, or based on user’s feedback. We anticipate, four to six years after the initial publication to start exploring adoption and impact. From there, we should be able to start discussing the need for an update, or changes in the dissemination and implementation strategies.
How do you plan to further disseminate CONSORT NUT to researchers and other stakeholders in the nutrition field?
We will invest in social media dissemination to engage with the main guidance target populations of nutrition researchers and other stakeholders, as well as to inform the general public about the importance of transparent and complete reporting of nutrition RCTs.
We will develop a website for the STAR-NUT initiative, where all publications and respective resources (e.g., checklists, pools of good reporting examples, and reporting quality evaluation tools) will be freely available for download. The STAR-NUT website will include dedicated spaces and features to motivate users’ exchange of experiences.
We are working together with nutrition societies and associations to develop the recommendations. We intend to keep these partnerships after the project is finished and use venues such as newsletters and events organised by these groups to share the guidance and associated resources.
It is therefore clear that there is a desire to create a scientific society that is aware of the gaps in nutritional interventions and that, right from the initial stages of Dr. Schlϋssel’s ambitious research project, there is ample scope for optimising the reporting and interpretation of the results obtained, should any limitations emerge in the development of the guidelines.
- Schulz KF, Altman DG, Moher D; CONSORT Group. CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials. BMC Med. 2010 Mar 24;8:18.
- Butcher NJ, Monsour A, Mew EJ, Chan AW, Moher D, Mayo-Wilson E, Terwee CB, Chee-A-Tow A, Baba A, Gavin F, Grimshaw JM, Kelly LE, Saeed L, Thabane L, Askie L, Smith M, Farid-Kapadia M, Williamson PR, Szatmari P, Tugwell P, Golub RM, Monga S, Vohra S, Marlin S, Ungar WJ, Offringa M. Guidelines for Reporting Outcomes in Trial Reports: The CONSORT-Outcomes 2022 Extension. JAMA. 2022 Dec 13;328(22):2252-2264.
- Center for Open Science, Schlussel M et at. Securing Transparency And Reproducibility in studies of NUTritional interventions (STAR-NUT): A research programme to consolidate reporting standards for randomised controlled trials and systematic reviews of nutritional interventions, August 5 2022 osf.io/b38z9 [Accessed 27 April 2023]
- Pasqua M, Gallo A, Contesto e fasi iniziali di sviluppo del CONSORT-Nut: l’estensione delle linee guida per i trial controllati randomizzati in ambito nutrizionale, Medici Oggi, 7 febbraio, 2023. https://medicioggi.it/metodologia-della-ricerca/contesto-e-fasi-iniziali-di-sviluppo-del-consort-nut-lestensione-delle-linee-guida-per-i-trial-controllati-randomizzati-in-ambito-nutrizionale/ [Accessed 27 April 2023]