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 article published: the relationship between ADAMTS13 and MI

2015-06-16 14_26_12-Plasma ADAMTS13 levels and the risk of myocardial infarction_ an individual pati

this article is a collaboration with a lot of guys. initiated from the Milan group, we ended up with a quite diverse group of researchers to answers this question because of the methods that we used: the individual patient data meta-analysis. The best thing about this approach: you can pool the data from different studies, even while you can adjusted for potential sources of confounding in a similar manner (given that the data are available, that is). On themselves, these studies showed some mixed results. But in the end, we were able to use the combined data to show that there was an increase MI risk but only for those with very low levels of ADAMTS13. So, here you see the power of IPD meta-analysis!

The credits for this work go primarily to AM who did a great job of getting all PI’s on board, analysing the data and writing a god manuscript. The final version is not online, but you find the pre-publication on pubmed



New article published: review on obesity and venous thrombosis

Together with colleagues I worked on a review on the role of obesity as a risk factor for venous thrombosis. I’m second author on the article, which come online last week, and most work has been done by SKB from Norway, who is visiting our department for a full year.

The article is written from an epidemiological point of view and discusses several points that are worth mentioning here. First of all, obesity is an ill-defined concept: are we only talking BMI, or do also other measures of obesity need to be taken into account? Second, even when defined, the results are not always easy to interpret. In causal research there are a couple of things that need to be fulfilled before one can answer the question whether something is risk factor of disease. For example, BMI can be reduced by means of exercise   diet or disease, which all three have completely different effects on thrombosis risk. We discuss all these epidemiological problems, together with the existing body of evidence in the new article in seminars of thrombosis and hemostasis. These question are not only important for our understanding of thrombotic disease, but also to grasp the causal role of obesity in (cardiovascular) disease. This research question has in ast couple of years been put on the research agenda of the NEO study, on which perhaps more in the future.

The article, with the full title “Role of Obesity in the Etiology of Deep Vein Thrombosis and Pulmonary Embolism: Current Epidemiological Insights” can be found via PubMed, or via my personal Mendeley page.

Paper selected as most important paper

The editors of Circulation: Cardiovascular Interventions perform perform a periodic  ‘Topic Review’  which (and I quote)

summarizes the most important manuscripts, as selected by the editors that have published in the Circulation portfolio. The studies included in this article represent the most noteworthy research in the area of peripheral arterial disease. (Circ Cardiovasc Interv. 2012;5:e39-e44.)

Our research on the effect of activation of the intrinsic coagulation proteins and their effects on ischaemic stroke risk -and not on myocardial infarction risk- was selected as one of the most important manuscripts int he field of peripheral arterial disease. This study was performed in collaboration with the Maastricht University Medical Center. The summary by these editors can be read below.

Continue reading “Paper selected as most important paper”

ISTH 2013 Amsterdam

The ISTH 2013 will be held in Amsterdam. This is a nice opportunity for Dutch researchers to really show how a nice conference should be: work hard during intensive debates on good research during the day and relax, drink and meetup with old friends in the evening.

Today I got an email asking me to help in abstract reviewing committee. This is not the first time to get such a request, but being a member of the ISTH and having most of my research n the topic of thrombosis, I feel this is truly an honor.

As a sidenote, I made a remark in an earlier post on the open system of reviewing: should every reviewer relinquish their anonymity?  This is not the case in this abstract selection committee, but there is at least a measure to prevent old boys network bias: all abstract are reviewed and scored in a blinded fashion. This does not prevent that persons can be identified by knowing their previous and ongoing work, but at least it helps to prevent -unconscious- preferential reviewing and scoring.