Three new papers – part III

As explained here and here, I temporarily combine the announcements of published papers in one blog to save some time. This is part III, where I focus on ordinal outcomes. Of all recent papers, these are the most exciting to me, as they really are bringing something new to the field of thrombosis and COVID-19 research.

Measuring functional limitations after venous thromboembolism: Optimization of the Post-VTE Functional Status (PVFS) Scale. I have written about our call to action, and this is the follow-up paper, with research primarily done in the LUMC. With input from patients as well as 50+ experts through a Delphi process, we were able to optimize our initial scale.

Confounding adjustment performance of ordinal analysis methods in stroke studies. In this simulation study, we show that ordinal data from observational can also be analyzed with a non-parametric approach. Benefits: it allows us to analyze without the need of the proportional odds assumption and still get an easy to understand point estimate of the effect.

The Post-COVID-19 Functional Status (PCFS) Scale: a tool to measure functional status over time after COVID-19. In this letter to the European Respiratory, colleagues from Leiden, Maastricht, Zurich, Mainz, Hasselt, Winterthur, and of course Berlin, we propose to use a scale that is basically the same as the PVFS to monitor and study the long term consequence of COVID-19.

Three new papers published – part II

In my last post, I explained why I am at the moment not writing one post per new paper. Instead, I group them. This time with a common denominator, namely the role of cardiac troponin and stroke:

High-Sensitivity Cardiac Troponin T and Cognitive Function in Patients With Ischemic Stroke. This paper finds its origins in the PROSCIS study, in which we studied other biomarkers as well. In fact, there is a whole lot more coming. The analyses of these longitudinal data showed a – let’s say ‘medium-sized’ – relationship between cardiac troponin and cognitive function. A whole lot of caveats – a presumptive learning curve, not a big drop in cognitive function to work with anyway. After all, these are only mild to moderately affected stroke patients.

Association Between High-Sensitivity Cardiac Troponin and Risk of Stroke in 96 702 Individuals: A Meta-Analysis. This paper investigates several patient populations -the general population, increased risk population, and stroke patients. The number of patients individuals in the title might, therefore, be a little bit deceiving – I think you should really only look at the results with those separate groups in mind. Not only do I think that the biology might be different, the methodological aspects (e.g. heterogeneity) and interpretation (relative risks with high absolute risks) are also different.

Response by Siegerink et al to Letter Regarding Article, “Association Between High-Sensitivity Cardiac Troponin and Risk of Stroke in 96 702 Individuals: A Meta-Analysis”. We did the meta-analysis as much as possible “but the book”. We pre-registered our plan and published accordingly. This all to discourage ourselves (and our peer reviewers) to go and “hunt for specific results”. But then there was a letter to the editor with the following central point: Because in the subgroup of patients with material fibrillation, the cut-offs used for the cardiac troponin are so different that pooling these studies together in one analysis does not make sense. At first glance, it looks like the authors have a point: it is difficult to actually get a very strict interpretation from the results that we got. This paper described our response. Hint: upon closer inspection, we do not agree and make a good counterargument (at least, that’s what we think).

Three new papers published

Normally I publish a new post for each new paper that we publish. But with COVID-19, normal does not really work anymore. But i don’t want to completely throw my normal workflow overboard. Therefore, a quick update on a couple of publications, all in one blogpost, yet without a common denominator:

Stachulski, F., Siegerink, B. and Bösel, J. (2020) ‘Dying in the Neurointensive Care Unit After Withdrawal of Life-Sustaining Therapy: Associations of Advance Directives and Health-Care Proxies With Timing and Treatment Intensity’, Journal of Intensive Care Medicine A paper about the role of advanced directives and treatment in the neurointensive care unit. Not normally the topic I publish about, as the severity of disease in these patients is luckily not what we normally see in stroke patients.

Impact of COPD and anemia on motor and cognitive performance in the general older population: results from the English longitudinal study of ageing. This paper makes use of the ELSA study – an open-access database – and hinges on the idea that sometimes two risk factors only lead to the progression of disease/symptoms if they work jointly. This idea behind interaction is often “tested” with a simple statistical interaction model. There are many reasons why this is not the best thing to do, so we also looked at biological (or additive interaction).

Thrombo-Inflammation in Cardiovascular Disease: An Expert Consensus Document from the Third Maastricht Consensus Conference on Thrombosis. This is a hefty paper, with just as many authors as pages it seems. But this is not a normal paper – it is the consensus statement of the thrombosis meeting last year in Maastricht. I really liked that meeting, not only because I got to see old friends, but also because of a number of ideas and papers were the product of this meeting. This paper is, of course, one of them. But after this one, some papers on the development of an ordinal outcome for functional status after venous thrombosis. But they will be part of a later blog post.

New paper – Improving the trustworthiness, usefulness, and ethics of biomedical research through an innovative and comprehensive institutional initiative

I report often on this blog about new papers that I have co-authored. Every time I highlight something that is special about that particular publication. This time I want to highlight a paper that I co-authored, but also didn’t. Let me explain.

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000576#sec014

The paper, with the title, Improving the trustworthiness, usefulness, and ethics of biomedical research through an innovative and comprehensive institutional initiative, was published in PLOS Biology and describes the QUEST center. The author list mentions three individual QUEST researchers, but it also has this interesting “on behalf of the QUEST group” author reference. What does that actually mean?

Since I have reshuffled my research, I am officially part of the QUEST team, and therefore I am part of that group. I gave some input on the paper, like many of my colleagues, but nowhere near enough to justify full authorship. That would, after all, require the following 4(!) elements, according to the ICMJE,

  • Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND
  • Drafting the work or revising it critically for important intellectual content; AND
  • Final approval of the version to be published; AND
  • Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

This is what the ICMJE says about large author groups: “Some large multi-author groups designate authorship by a group name, with or without the names of individuals. When submitting a manuscript authored by a group, the corresponding author should specify the group name if one exists, and clearly identify the group members who can take credit and responsibility for the work as authors. The byline of the article identifies who is directly responsible for the manuscript, and MEDLINE lists as authors whichever names appear on the byline. If the byline includes a group name, MEDLINE will list the names of individual group members who are authors or who are collaborators, sometimes called non-author contributors, if there is a note associated with the byline clearly stating that the individual names are elsewhere in the paper and whether those names are authors or collaborators.”

I think that this format should be used more, but that will only happen if people take the collaborator status seriously as well. Other “contribution solutions” can help to give some insight into what it means to be a collaborator, such as a detailed description like in movie credits or a standardized contribution table. We have to start appreciating all forms of contributions.

On the value of data – routinely vs purposefully

I listen to a bunch of podcasts, and the podcast “The Pitch” is one of them. In that podcast, Entrepreneurs of start-up companies pitch their ideas to investors. Not only is it amusing to hear some of these crazy business ideas, but the podcast also help me to understand about professional life works outside of science. One thing i learned is that it is ok if not expected, to oversell by about a factor 142.

Another thing that I learned is the apparent value of data. The value of data seems to be undisputed in these pitches. In fact, the product or service the company is selling or providing is often only a byproduct: collecting data about their users which subsequently can be leveraged for targeted advertisement seems to be the big play in many start-up companies.

I think this type of “value of data” is what it is: whatever the investors want to pay for that type of data is what it is worth. But it got me thinking about the value of data that we actually collect in medical. Let us first take a look at routinely data, which can be very cheap to collect. But what is the value of the data? The problem is that routinely collected data is often incomplete, rife with error and can lead to enormous biases – both information bias as well as selection bias. Still, some research questions can be answered with routinely collected data – as long as you make some real efforts to think about your design and analyses. So, there is value in routinely collected data as it can provide a first glance into the matter at hand.

And what is the case for purposefully collected data? The idea behind this is that the data is much more reliable: trained staff collects data in a standardised way resulting in datasets without many errors or holes. The downside is the “purpose” which often limits the scope and thereby the amount collected data per included individual. this is the most obvious in randomised clinical trials in which often millions of euro’s are spent to answer one single question. Trials often do no have the precision to provide answers to other questions. So it seems that the data can lose it value after answering that single question.

Luckily, many efforts were made to let purposefully collected keep some if its value even after they have served their purpose. Standardisation efforts between trials make it now possible to pool the data and thus obtain a higher precision. A good example from the field of stroke research is the VISTA collaboration, i.e the Virtual International Stroke Trials Archive”. Here, many trials – and later some observational studies – are combined to answer research questions with enough precision that otherwise would never be possible. This way we can answer questions with high quality of purposefully collected data with numbers otherwise unthinkable.

This brings me to a recent paper we published with data from the VISTA collaboration: “Early in-hospital exposure to statins and outcome after intracerebral haemorrhage”. The underlying question whether and when statins should be initiated / continued after ICH is clinically relevant but also limited in scope and impact, so is it justified to start a trial? We took the the easier and cheaper solution and analysed the data from VISTA. We conclude that

… early in-hospital exposure to statins after acute ICH was associated with better functional outcome compared with no statin exposure early after the event. Our data suggest that this association is particularly driven by continuation of pre-existing statin use within the first two days after the event. Thus, our findings provide clinical evidence to support current expert recommendations that prevalent statin use should be continued during the early in-hospital phase.1921

link

And this shows the limitations of even well collected data from RCT: as long as the exposure of interest is potentially provided to a certain subgroup (i.e. Confounding by indication), you can never really be certain about the treatment effects. To solve this, we would really need to break the bond between exposure and any other clinical characteristic, i.e. randomize. That remains the golden standard for intended effects of treatments. Still, our paper provided a piece of the puzzle and gave more insight, form data that retained some of its value due to standardisation and pooling. But there is no dollar value that we can put on the value of medical research data – routinely or purposefully collected alike- as it all depends on the question you are trying to answer.

Our paper, with JD in the lead, was published last year in the European Stroke Journal, and can be found here as well as on my Publons profile and Mendeley profile.

The story of a paper on the relationship between cancer and stroke that is both new and not so new.

Science is not quick. In fact, it is slow most of the time. Therefore, most researchers work on multiple papers at the same time. This is not necessarily bad, as parallel activities can be leveraged to increase the quality of the different projects. But sometimes this approach leads to significant delays. Imagine a paper that is basically done, and then during the peer review process, all the lead figures in the author team get different positions. Perhaps a Ph.D. student moves institutes for a post-doc, or junior doctors finish their training and set up their own practices, or start their demanding clinical duties in an academic medical center. All these steps are understandable and good for science in general but can hurt the speediness of individual papers.

This happened for example with a recently published paper in the Dutch PSI study. I say recently published because the work started > 5 years ago and has been finished more or less for the majority of that time. In this paper, we show that cancer prevalence is higher for stroke patients. But not all cancers are affected: it is primarily bladder cancer and head and neck type of effect. This might be explained by the shared risk factor smoking (bladder cancer, repository tract) and perhaps cancer treatment (central nervous system/ head and neck cancer). Not world shocking results with direct clinical implications, but relevant if you want to have a clear understanding of the consequences of cancer.


Now don’t get me wrong, I am very glad we, in the end, got all their ducks in a row and find a good place for the paper to be published. But the story is also a good warning: It was the willpower of some in the team to make this happen. Next time such a situation comes around, we might not have the right people with will right amount of power to keep on going with a paper like this. 

How to avoid this? Is “pre-print” the solution? I am not sure. On the surface, it indeed seems the answer, as it will give others at least the chance to see the work we did. But I am a firm believer that some form of peer review is necessary – just ‘dumping’ papers on a pre-print server is really a non-solution and I am afraid that a culture like that will only diminish the drive to get things formally published is even lower when manuscripts are already in the public domain. Post-publication peer review then? I am also skeptical here, as I the idea of pre-publication peer review is so deeply embedded within the current scientific enterprise that  I do not see post-publication peer review playing a big role anytime soon. The lack of incentive for peer review – let alone post-publication peer review – is really not helping us to make the needed changes anytime sooner. 


Luckily, there is a thing called intrinsic motivation, and I am glad that JW and LS had enough to get this paper published. The paper, with the title “Cancer prevalence higher in stroke patients than in the general population: the Dutch String-of-Pearls Institute (PSI) Stroke study. is published in European Journal of Neurology and can be found on Pubmed, as well as on my Mendeley and Publons profile.

Helping patients to navigate the fragmented healthcare landscape in Berlin: the NAVICARE stroke-atlas

the cover the Berlin Stroke Atlas

Research on healthcare delivery can only do so much to improve the lives of patients. Identifying the weak spots is important to start off with, but is not going to help patients one bit if they don’t get information that is actually useful let alone in time.

It is for that reason that the NAVICARE project not only focusses on doing research but also to provide information for patients, as well as bringing healthcare providers together in the NAVICARE network. The premise of NAVICARE is that somehow we need to help patients to navigate the fragmented healthcare landscape. We do so by using the diseases stroke and lung cancer as model diseases, prototypical diseases that help us focus our attention.

One deliverable is the stroke atlas: a document that provides different healthcare providers – and people and organizations who can help you in the broadest sense possible once you or your loved one is affected by a stroke. This stroke atlas, in conjunction with our personal approach at the stroke service point of the CSB/BSA, will help our patients. You can find the stroke atlas here (in German of course).

But this is only a first step. the navigator model is currently being further developed, for which NAVICARe has received additional funding this summer. I will not be part of those steps (see my post on my reshuffled research focus), but others at the CSB will.