Advancing prehospital care of stroke patients in Berlin: a new study to see the impact of STEMO on functional outcome

There are strange ambulances driving around in Berlin. They are the so-called STEMO cars, or Stroke Einsatz Mobile, basically driving stroke units. They have the possibility to make a CT scan to rule out bleeds and subsequently start thrombolysis before getting to the hospital. A previous study showed that this descreases time to treatment by ~25 minutes. The question now is whether the patients are indeed better of in terms of functional outcome. For that we are currently running the B_PROUD study of which we recently published the design here.

How to set up a research group

A couple of weeks ago I wrote down some thoughts I had while writing a paper for the JTH series on Early Career Researchers. I was asked to write how one sets up a research group, and the four points I described in my previous post can be recognised in the final paper.

But I also added some reading tips in the paper. reading on a particular topic helps me not only to learn what is written in the books, but also to get my mind in a certain mindset. So, when i knew that i was going to take over a research group in Berlin I read a couple of books, both fiction and non fiction. Some where about Berlin (e.g. Cees Nootebooms Berlijn 1989/2009), some were focussed on academic life (e.g. Porterhouse Blue). They help to get my mind in a certain gear to help me prepare of what is going on. In that sense, my bookcase says a lot about myself.

The number one on the list of recommended reads are the standard management best sellers, as I wrote in the text box:

// Management books There are many titles that I can mention here; whether it the best-seller Seven Habits of Highly Effective People or any of the smaller booklets by Ken Blanchard, I am convinced that reading some of these texts can help you in your own development as a group leader. Perhaps you will like some of the techniques and approaches that are proposed and decide to adopt them. Or, like me, you may initially find yourself irritated because you cannot envision the approaches working in the academic setting. If this happens, I encourage you to keep reading because even in these cases, I learned something about how academia works and what my role as a group leader could be through this process of reflection. My absolute top recommendation in this category is Leadership and Self-Deception: a text that initially got on my nerves but in the end taught me a lot.

I really think that is true. You should not only read books that you agree with, or which story you enjoy. Sometimes you can like a book not for its content but the way it makes you question your own preexisting beliefs and habits. But it is true that this sometimes makes it difficult to actually finnish such a book.

Next to books, I am quite into podcasts so I also wrote

// Start up. Not a book, but a podcast from Gimlet media about “what it’s really like to get a business off the ground.” It is mostly about tech start-ups, but the issues that arise when setting up a business are in many ways similar to those you encounter when you are starting up a research group. I especially enjoyed seasons 1 and 3.

I thought about including the sponsored podcast “open for business” from Gimlet Creative, as it touches upon some very relevant aspects of starting something new. But for me the jury is still out on the “sponsored podcast” concept  – it is branded content from amazon, and I am not sure to what extent I like that. For now, i do not like it enough to include it in the least in my JTH-paper.

The paper is not online due to the summer break,but I will provide a link asap.

– update 11.10.2016 – here is a link to the paper. 





Pregnancy loss and risk of ischaemic stroke and myocardial infarction

2016-04-08 13_36_29-Posteingang - - Outlook

Together with colleagues I worked on a paper on relationship between pregnancy, its complications and stroke and myocardial infarction in young women, which just appeared online on the BJH website.

The article, which analyses data from the RATIO study, concludes that only if you have multiple pregnancy losses, your risk of stroke is increased (OR 2.4) compared to those who never experienced a pregnancy loss. The work was mainly done by AM, and is a good example of international collaborations where we benefitted from the expertise of all team members.

The article, with the full title “Pregnancy loss and risk of ischaemic stroke and myocardial infarction” can be found via PubMed, or via my personal Mendeley page.

Causal Inference in Law: An Epidemiological Perspective


Finally, it is here. The article I wrote together with WdH, MZ and RM was published in the European Journal of Risk and Regulation last week. And boy, did it take time! This whole project, an interdisciplinary project where epidemiological thinking was applied to questions of causal inference in tort law, took > 3 years – with only a couple of months writing… the rest was waiting and waiting and waiting and some peer review. but more on this later.

First some content. in the article we discuss the idea of proportional liability that adheres to the epidemiological concept of multi-causality. But the article is more: as this is a journal for non epidemiologist, we also provide a short and condensed overview of study design, bias and other epidemiological concepts such as counterfactual thinking. You might have recognised the theme from my visits to the Leiden Law school for some workshops. The EJRR editorial describes it asas: “(…) discuss the problem of causal inference in law, by providing an epidemiological viewpoint. More specifically, by scrutinizing the concept of the so-called “proportional liability”, which embraces the epidemiological notion of multi-causality, they demonstrate how the former can be made more proportional to a defendant’s relative contribution in the known causal mechanism underlying a particular damage.”

Getting this thing published was tough: the quality of the peer review was low (dare I say zero?),communication was difficult, submission system flawed etc. But most of all the editorial office was slow – first submission was June 2013! This could be a non-medical journal thing, i do not know, but still almost three years. And this all for an invited article that was planned to be part of a special edition on the link between epi and law, which never came. Due several delays (surprise!) of the other articles for this edition, it was decided that our article is not waiting for this special edition anymore. Therefore, our cool little insight into epidemiology now seems to be lost between all those legal and risk regulation articles. A shame if you ask me, but I am glad that we are not waiting any longer!

Although i do love interdisciplinary projects, and I think the result is a nice one, I do not want to go through this process again. No more EJRR for me.

Ow, one more thing… the article is behind a pay wall and i do not have access through my university, nor did the editorial office provide me with a link to a pdf of the final version. So, to be honest, I don’t have the final article myself! Feels weird. I hope EJRR will provide me with a pdf quite soon. In the meantime, anybody with access to this article, please feel free to send me a copy!

First results from the RATIO follow up study

Another article got published today in the JAMA Int Med, this time the results from the first analyses of the RATIO follow-up data. For these data, we linked the RATIO study to the dutch national bureau of statistics (CBS), to obtain 20 years of follow-up on cardiovascular morbidity and mortality. We first submitted a full paper, but later we downsized to a research letter with only 600 words. This means that only the main message (i.e. cardiovascular recurrence is high, persistent over time and disease specific) is left.

It is a “Leiden publication”, where I worked together with AM and FP from Milano. Most of the credit of course goes to AM, who is the first author of this piece. The cool thing about this publication is that the team worked very hard on it for a long time (data linking and analyses where not an easy thing to do, as well as changing from 3000 words to 600 in just a week or so), and that in the end all the hard work paid off. But next to the hard work, it is also nice to see results being picked up by the media. The JAMA Int Med put out an international press release, whereas the LUMC is going to publish its own Dutch version. In the days before the ‘online first’ publication I already answered some emails from writers for medical news sites, some with up to 5.000K views per month. I do not know if you think that’s a lot, but for me it is. The websites that cover this story can be found here (, / / / / and perhaps more to come. Why not just take a look at the Altmetric of this article).

– edit 26.11.2015: a dutch press release from the LUMC can be found here) – edit: oops, has a published great report/interview, but used a wrong title…”Repeat MI and Stroke Risks Defined in ‘Younger’ Women on Oral Contraceptives”. not all women were on OC of course.

Of course, @JAMAInternalMed tweeted about it


The article, with the full title Recurrence and Mortality in Young Women With Myocardial Infarction or Ischemic Stroke: Long-term Follow-up of the Risk of Arterial Thrombosis in Relation to Oral Contraceptives (RATIO) Study can be found via JAMA Internal Medicine or via my personal Mendeley page.

As I reported earlier, this project is supported by a grant from the LUF den Dulk-Moermans foundation, for which we are grateful.

New article: Lipoprotein (a) as a risk factor for ischemic stroke: a meta-analysis


Together with several co-authors, with first author AN in the lead, we did a meta analyses on the role of Lp(a) as a risk factor of stroke. Bottomline, Lp(a) seems to be a risk factor for stroke, which was most prominently seen in the young.

The results are not the only reason why I am so enthusiastic by this article. It is also about the epidemiological problem that AN encountered and we ended up discussing over coffee. The problem: the different studies use different categorisations (tertiles, quartiles, quintiles). How to use these data and pool them in a way to get a valid and precise answer to the research question? In the end we ended up using the technique proposed used by D Danesh et al. JAMA. 1998;279(18):1477-1482 that uses the normal distribution and the distances in SD. A neat technique, even though it assumes a couple of things about the uniformity of the effect over the range of the exposure. An IPD would be better, as we would be free to investigate the dose relationship and we would be able to keep adjustment for confounding uniform, but hey… this is cool in itself!

The article can be found on pubmed and on my mendeley profile.

New articles published: hypercoagulability and the risk of ischaemic stroke and myocardial infarction

Ischaemic stroke + myocardial infarction = arterial thrombosis. Are these two diseases just two sides of the side coin? Well, most if the research I did in the last couple of years tell a different story: most times,hypercoagulability has a stronger impact on the risk of ischaemic stroke at least when compared to myocardial infarction. And when in some cases this was not the case, at least it as clear that the impact was differential. But these papers I published were all single data dots, so we needed to provide an overview of all these data points to get the whole picture. And we did so by publishing two papers, one in the JTH and one in PLOS ONE.

The first paper is a general discussion of the results from the RATIO study, basically an adaptation from my discussion chapter of my thesis (yes it took some time to get to the point of publication, but that’s a whole different story), with a more in-depth discussion to what extent we can draw conclusions from these data. We tried to fill in the caveats (limited number of markers, only young women, only case-control, basically single study) of the first study with our second publication. Here we did the same trick, but in a systematic review.This way, our results have more external validity, while we ensured the internal validity by only including studies that studied both diseases and thus ruling out large biases due to differences in study design. I love these two publications!

You can find these publications through their PMID 26178535 and 26178535, or via my mendeley account.

PS the JTH paper has PAFs in them. Cool!