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. 2021 Dec 6;36(3):846–856. doi: 10.1007/s12028-021-01386-y

Can We Cluster ICU Treatment Strategies for Traumatic Brain Injury by Hospital Treatment Preferences?

Iris E Ceyisakar 1,2,✉, Jilske A Huijben 1, Andrew I R Maas 2, Hester F Lingsma 1, Nikki van Leeuwen 1; CENTER-TBI participants and investigators
PMCID: PMC9110448  PMID: 34873673

Abstract

Background

In traumatic brain injury (TBI), large between-center differences in treatment and outcome for patients managed in the intensive care unit (ICU) have been shown. The aim of this study is to explore if European neurotrauma centers can be clustered, based on their treatment preference in different domains of TBI care in the ICU.

Methods

Provider profiles of centers participating in the Collaborative European Neurotrauma Effectiveness Research in TBI study were used to assess correlations within and between the predefined domains: intracranial pressure monitoring, coagulation and transfusion, surgery, prophylactic antibiotics, and more general ICU treatment policies. Hierarchical clustering using Ward’s minimum variance method was applied to group data with the highest similarity. Heat maps were used to visualize whether hospitals could be grouped to uncover types of hospitals adhering to certain treatment strategies.

Results

Provider profiles were available from 66 centers in 20 different countries in Europe and Israel. Correlations within most of the predefined domains varied from low to high correlations (mean correlation coefficients 0.2–0.7). Correlations between domains were lower, with mean correlation coefficients of 0.2. Cluster analysis showed that policies could be grouped, but hospitals could not be grouped based on their preference.

Conclusions

Although correlations between treatment policies within domains were found, the failure to cluster hospitals indicates that a specific treatment choice within a domain is not a proxy for other treatment choices within or outside the domain. These results imply that studying the effects of specific TBI interventions on outcome can be based on between-center variation without being substantially confounded by other treatments.

Trial registration

We do not report the results of a health care intervention.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01386-y.

Keywords: Provider profiling, Between-hospital variation, Comparative effectiveness research, Traumatic brain injury

Introduction

Traumatic brain injury (TBI) remains a major global health issue, being one of the leading causes of mortality and disability with 2.5 million reported cases each year within the European Union and United Kingdom [1–3].

The primary injury is irreversible, and the main focus of treatment is on avoiding and limiting secondary brain damage. In patients with severe TBI, this is often informed by intracranial pressure (ICP) or brain-metabolic monitoring. Previous studies have debated monitoring and treatment choices in TBI [4], and evidence underpinning monitoring and treatment recommendations is relatively weak.

This uncertainty is reflected in large between-center differences in processes and outcomes for patients treated in the intensive care unit (ICU) after TBI [5, 6]. The differences in treatment policy can be exploited to study treatment effectiveness in comparative effectiveness research (CER). One approach to CER is to identify the most effective treatment, by comparing hospitals’ treatment choices and relating these to their outcomes. In recent years, this approach has gained popularity in TBI as a complementary approach to the evidence base provided by randomized controlled trials [7]. CER can be used to identify a causal relationship between a treatment and outcome if known and unknown confounders can be adequately adjusted for and if the treatment under investigation is not correlated with other treatment policies. To date, it is unknown whether certain treatment strategies in patients with TBI are related. Such knowledge would be essential when comparing outcomes on a hospital level within the framework of CER to study whether differences in outcomes can be attributed to the separate interventions.

If, on the other hand, multiple treatment choices are correlated, it gives the possibility to group these together and identify hospitals with, for example, a more aggressive treatment strategy. Conclusions could then only be drawn on a very general level: whether a more aggressive or a more passive treatment strategy is more effective. Within the framework of CER, however, this would make it impossible to study specific treatments and their effect on outcome because some specific treatment aspects within the strategy may be beneficial and others even harmful.

Focusing on the domains of ICP monitoring, prophylactic antibiotics, transfusion targets, and general ICU management, our aim was to investigate correlations between treatment policies and to explore if European neurotrauma centers can be clustered based on their treatment strategy in patients with TBI.

Methods

Collaborative European Neurotrauma Effectiveness Research in TBI Study

The Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study is a prospective longitudinal multicenter observational study conducted across Europe and Israel (ClinicalTrials.gov ref. NCT02210221) [8]. CENTER-TBI aims to better characterize and describe TBI in a European context and to further advance the care of patients with TBI within the broader international framework of the International Initiative for TBI Research (https://intbir.nih.gov/).

Principal investigators of each participating center in this study received questionnaires about the structures (type of facilities and equipment, the qualifications of medical staff and their organizations) and processes (treatment policies in different phases of TBI care) of their center: the provider profiling questionnaires [9]. Participants were explicitly asked for their general policy rather than for individual treatment preferences. General policy was defined as ‘‘the way the large majority of patients (> 75%) with a certain indication would be treated.’’ Detailed information about the content, development, and validation of the original 321 questions can be found in an earlier publication [9]. Baseline characteristics for centers were described using frequencies and percentages.

Predefined Treatment Domains

We selected 58 questions on the basis of expert consensus concerning care in the ICU setting, covering the domains of coagulation and transfusion, neurosurgery, ICP monitoring, prophylactic antibiotics, and general management. The selected questions were chosen before the analysis on the basis of clinical relevance. Follow-up, conditional questions (“if you answered A, then specify…”) and all open questions were excluded, aiming to obtain a standardized overview of treatment approaches.

Questions from predefined domains were chosen to enable stratification of hospitals over multiple domains. To determine possible underlying treatment strategies, polychoric correlation coefficients between questions were calculated [10]. Correlations were visualized with correlation plots, using only absolute values (between 0 and 1), as any negative correlations were as relevant as positive correlations in determining treatment strategies. Missing answers were disregarded for calculation of the correlation. Of the 58 questions, 44 questions were complete, and the other 12 had up to 8 out of 66 answers missing. We looked at correlations of questions within the predefined domains (exploring consistency in treatment policies within a specific domain) as well as correlations between the domains (exploring interdependencies of treatments between domains).

Regrouping of Questions

After correlations were determined, the questions were grouped based on the data, ignoring the previously defined domains, with an hierarchical cluster analysis using Ward’s minimum variance method, to group together the questions with the highest similarity [11]. This is an agglomerative clustering method in which the data points (questions) are clustered (across all domains) in different steps until only questions with the greatest similarity form a cluster. We used the Bayesian inference criterion for k-means to determine the number of clusters that were to be formed [12, 13].

Heat Maps

By using the same clustering algorithm, heat maps were made for each newly formed group of questions. Heat maps allow for the recognition of patterns in the preference of hospitals and made it possible to determine whether we could discern certain types of hospitals. This was performed on all complete cases: centers with missing answers within the cluster of questions were disregarded. For cluster two, 53 of the 66 participating hospitals were included in the heat map; for cluster five, 47 of the hospitals were included, and all other clusters included all participating hospitals. All analysis were performed in R version 3.3.0 using the following packages: pheatmap, RColorBrewer, foreign, cluster, corrplot, dplyr, and fmsb [14–21].

Results

CENTER-TBI Study

Provider profiling questionnaires were completed in 66 centers (97% response rate), mainly by intensivists (n = 33, 50%) and neurosurgeons (n = 23, 35%), but otherwise by administrative staff (n = 11, 17%), neurologists (n = 5, 8%), anesthesiologists (n = 5, 8%), and a trauma surgeon (n = 1, 2%). The majority of these centers had an academic affiliation (n = 60, 91%). The center characteristics are described in Supplementary Table 1 and in more detail in a previous publication [9].

Correlation within and Between Domains

Correlation between treatment policies within the predefined domains was variable (Fig. 1a–e). Correlations within the domain of prophylactic antibiotics (mean correlation coefficient = 0.6, range 0.4–0.8) ranged from moderate to strong, but questions were based on only one very specific topic. The correlation within the other domains was shown to be much lower (Table 1). Correlations between domains were lower, with mean correlation coefficients of 0.2 for each domain correlated with all other domains (Table 1 and Fig. 1f).

Fig. 1.

Fig. 1

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Correlation plot showing correlations between questions, grouped (squares) to show the five predefined domains: intracranial pressure (ICP) monitoring (a), coagulation and transfusion (b), surgery (c), prophylactic antibiotics (d), and more general ICU treatment policies (e), and correlations within and between the predefined domains (f). The correlations were calculated with Pearson correlations, and a higher correlation is visualized as a darker blue. ICU intensive care unit

Table 1.

Overview of the correlation coefficient calculated for questions within and between predefined domains

Domain Mean (SD) Min Max Number of questions
Correlation coefficients for correlation between questions within the predefined domains
 Coagulation & transfusion targets 0.2 (0.2) 0 0.9 8
 Neurosurgery 0.2 (0.2) 0 0.8 19
 ICP monitoring 0.3 (0.2) 0 0.9 17
 Prophylactic antibiotics 0.6 (0.2) 0.4 0.8 4
 General management 0.3 (0.2) 0 1 9
Correlation coefficients for questions between the predefined domains
 Coagulation & transfusion targets versus rest 0.2 (0.1) 0 0.7
 Neurosurgery versus rest 0.2 (0.2) 0 0.9
 ICP monitoring versus rest 0.2 (0.2) 0 0.9
 Prophylactic antibiotics versus rest 0.2 (0.2) 0 0.9
 General management versus rest 0.2 (0.1) 0 0.7
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We used the Pearson correlation coefficient to determine correlations within domains (upper panel) and between domains (lower panel)

ICP intracranial pressure, Max maximum, Min minimum, SD standard deviation

Data-Driven Cluster Analysis

The cluster analysis revealed four clusters, one fewer compared with the clinically determined domains (Fig. 2). The grouping remained very similar to the predefined domains, especially for the original domain of neurosurgery. A few questions did correlate with other subdomains, mainly due to overlap in topic of the questions. For example, the question, “Is a coagulation panel assessed prior to insertion of an ICP monitoring device?” could span the domains of coagulation and transfusion as well as ICP monitoring (Supplementary Table 2).

Fig. 2.

Fig. 2

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Sankey diagram showing regrouping of questions according to hierarchical clustering. On the left, questions are grouped according to what was decided to be clinically relevant. On the right, the questions are regrouped, and the shifting of questions is visualized, with a thicker gray line indicating a larger number of questions. ICP, intracranial pressure

Grouping of Hospitals

No hospital types were discernable in the heat maps made for each cluster of questions (Fig. 3, for the heat map of all the questions see Suppl. Figure 2). The heat maps served as a visual indication of the possibility to cluster the hospitals. Based on the visualization of these data, we have decided that further clustering should not be done. Although most similar questions had been grouped together, heat maps showed no clear pattern in the preferences of the hospitals, indicating that they could not be grouped based on their treatment tendencies.

Fig. 3.

Fig. 3

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Heat maps showing similarities between hospitals in answers given to questions within the previously determined clusters of questions. This was based on the hierarchical cluster analyses. The colors in the heat map relate to the specific answers: within a column, the same color indicates that two hospitals have given the same answer to the corresponding question. ICP intracranial pressure

Discussion

This study aimed to group European neurotrauma centers into clusters based on their treatment preference in patients with TBI in a variety of domains. Hospitals could not be clustered based on their reported choices of treatment within the five domains of the provider profiling questionnaires. These results imply that it is unlikely that hospitals can be categorized as a certain type of hospital based on the treatment strategies they follow across multiple domains of monitoring and treatment in patients with TBI.

The lack of evident treatment policies across multiple domains might be explained by a lack of strong evidence of the effectiveness of certain treatments, leading to weak guideline recommendations, which may cause heterogeneity in treatment strategies across Europe [22]. However, it could also be the result of more individualized medicine, in which case treatment strategies are based on the individual patient and monitoring characteristics [1]. TBI is a complex heterogeneous syndrome that might not be captured with a single treatment strategy. With the advanced monitoring devices and the range of brain and system targeted therapies available, variation between centers in treatment strategies is likely.

For future statistical analyses, our finding that the questions correlated mainly within their previously defined subdomain implies that all elements of TBI treatment can, and have to, be analyzed separately rather than combining different domains when relations between treatment and outcome are explored. The correlation of some questions with questions from a different domain could be attributed to overlap in the subject of the questions. Other reasons for correlations with other domains could be dependent on who is responsible for the decisions being made: for example, decisions for treatment of the patient are made by the neurosurgeon would have a higher chance of correlating with other decisions made by that neurosurgeon.

Based on our study, we may conclude that future CER analyses will be likely to measure a direct effect of one intervention on outcome instead of a general effect of multiple treatment effects. This is important knowledge to continue CER research within TBI, in which outcomes between centers are compared to find underlying differences in treatment. Although unmeasured confounders will always have to be considered, knowing that multiple treatments are not interdependent is a first step in further elucidating the effects of treatment choices. This study has its strengths and limitations. This study was conducted in multiple neurotrauma centers across Europe. The development and dissemination of the questionnaires was done in different phases. Two methods were used to determine relations between and within certain treatment strategy domains. With hierarchical cluster analyses, we confirmed the results of correlation analyses. However, our study also has its limitations; in a survey study using provider profiling questionnaires, centers only indicate their treatment strategy and do not provide an objective measure of real-time practice. This could overestimate or underestimate the use of general policies. The centers included in this study are mostly academic medical centers, and a more heterogeneous group of care providers could have potentially shown a clearer division in hospital types. Previous studies from CENTER-TBI show that, even within the sample of mostly academic centers, substantial practice variation exists [23–25].

Further, the study is focused on hospitals in Europe, and it is possible that these findings cannot be extrapolated to other large regions, such as the United States.

Possibly better suited for the purpose of grouping hospitals would be a questionnaire that is more specific. Future research using a more detailed questionnaire might be a solution to increase reliability of indicated treatment preferences. More targeted questions could allow for a better and more thorough understanding. This would give insight into why decisions are made and by whom. However, the better we understand and the more specific the information is, the harder it will be to visualize, generalize, and simplify enough to be able to present it graphically.

This is the first study that studied underlying relations in treatment strategies, and these results need to be confirmed in other studies.

Conclusions

We found correlations in treatment policies within domains, especially for neurosurgical interventions, but no evidence that hospitals could be clustered, indicating that a specific treatment choice within a domain is not a proxy for other treatment choices within or outside the domain. Because we did not find an indication that some centers, in general, were more eager to treat or reach higher treatment intensity levels overall, future TBI analyses should be conducted per specific treatment item instead of per treatment domain. Furthermore, within the CER paradigm, this implies that analyzing effects of an intervention on outcome is likely to measure a direct effect of that intervention without being substantially confounded by a general effect of multiple treatments.

Supplementary Information

Below is the link to the electronic supplementary material.

12028_2021_1386_MOESM1_ESM.tiff (3.3MB, tiff)

Supplementary Figure 1. Correlation plot-showing correlations between questions, after questions have been grouped according to hierarchical clustering (TIFF 3344 KB)

12028_2021_1386_MOESM2_ESM.tiff (40MB, tiff)

Supplementary Figure 2. Heatmaps showing similarity between hospitals in answers given to question based on the hierarchical cluster analyses. The colors in the heatmap relate to the specific answers: within a column the same color indicates that two hospitals have given the same answer to the corresponding question (TIFF 40917 KB)

Supplementary file3 (DOCX 23 KB) (22.8KB, docx)

Acknowledgments

The authors thank all clinical and research staff at the CENTER-TBI sites for completing the provider profiling questionnaires. Data used in preparation of this manuscript were obtained in the context of CENTER-TBI, a large collaborative project with the support of the European Commission 7th Framework program (602150). The funder had no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.

The CENTER-TBI participants and investigators: Cecilia Åkerlund1, Krisztina Amrein2, Nada Andelic3, Lasse Andreassen4, Audny Anke5, Anna Antoni6, Gérard Audibert7, Philippe Azouvi8, Maria Luisa Azzolini9, Ronald Bartels10, Pál Barzó11, Romuald Beauvais12, Ronny Beer13, Bo-Michael Bellander14, Antonio Belli15, Habib Benali16, Maurizio Berardino17, Luigi Beretta9, Morten Blaabjerg18, Peter Bragge19, Alexandra Brazinova20, Vibeke Brinck21, Joanne Brooker22, Camilla Brorsson23, Andras Buki24, Monika Bullinger25, Manuel Cabeleira26, Alessio Caccioppola27, Emiliana Calappi27, Maria Rosa Calvi9, Peter Cameron28, Guillermo Carbayo Lozano29, Marco Carbonara27, Simona Cavallo17, Giorgio Chevallard30, Arturo Chieregato30, Giuseppe Citerio31, 32, Hans Clusmann33, Mark Coburn34, Jonathan Coles35, Jamie D. Cooper36, Marta Correia37, Amra Čović 38, Nicola Curry39, Endre Czeiter24, Marek Czosnyka26, Claire Dahyot-Fizelier40, Paul Dark41, Helen Dawes42, Véronique De Keyser43, Vincent Degos16, Francesco Della Corte44, Hugo den Boogert10, Bart Depreitere45, Đula Đilvesi46, Abhishek Dixit47, Emma Donoghue22, Jens Dreier48, Guy-Loup Dulière49, Ari Ercole47, Patrick Esser42, Erzsébet Ezer50, Martin Fabricius51, Valery L. Feigin52, Kelly Foks53, Shirin Frisvold54, Alex Furmanov55, Pablo Gagliardo56, Damien Galanaud16, Dashiell Gantner28, Guoyi Gao57, Pradeep George58, Alexandre Ghuysen59, Lelde Giga60, Ben Glocker61, Jagoš Golubovic46, Pedro A. Gomez62, Johannes Gratz63, Benjamin Gravesteijn64, Francesca Grossi44, Russell L. Gruen65, Deepak Gupta66, Juanita A. Haagsma64, Iain Haitsma67, Raimund Helbok13, Eirik Helseth68, Lindsay Horton69, Jilske Huijben64, Peter J. Hutchinson70, Bram Jacobs71, Stefan Jankowski72, Mike Jarrett21, Ji-yao Jiang58, Faye Johnson73, Kelly Jones52, Mladen Karan46, Angelos G. Kolias70, Erwin Kompanje74, Daniel Kondziella51, Evgenios Kornaropoulos47, Lars-Owe Koskinen75, Noémi Kovács76, Ana Kowark77, Alfonso Lagares62, Linda Lanyon58, Steven Laureys78, Fiona Lecky79,80, Didier Ledoux78, Rolf Lefering81, Valerie Legrand82, Aurelie Lejeune83, Leon Levi84, Roger Lightfoot85, Hester Lingsma64, Andrew I.R. Maas43, Ana M. Castaño-León62, Marc Maegele86, Marek Majdan20, Alex Manara87, Geoffrey Manley88, Costanza Martino89, Hugues Maréchal49, Julia Mattern90, Catherine McMahon91, Béla Melegh92, David Menon47, Tomas Menovsky43, Ana Mikolic64, Benoit Misset78, Visakh Muraleedharan58, Lynnette Murray28, Ancuta Negru93, David Nelson1, Virginia Newcombe47, Daan Nieboer64, József Nyirádi2, Otesile Olubukola79, Matej Oresic94, Fabrizio Ortolano27, Aarno Palotie95,96,97, Paul M. Parizel98, Jean-François Payen99, Natascha Perera12, Vincent Perlbarg16, Paolo Persona100, Wilco Peul101, Anna Piippo-Karjalainen102, Matti Pirinen95, Dana Pisica64, Horia Ples93, Suzanne Polinder64, Inigo Pomposo29, Jussi P. Posti 103, Louis Puybasset104, Andreea Radoi105, Arminas Ragauskas106, Rahul Raj102, Malinka Rambadagalla107, Isabel Retel Helmrich64, Jonathan Rhodes108, Sylvia Richardson109, Sophie Richter47, Samuli Ripatti95, Saulius Rocka106, Cecilie Roe110, Olav Roise111,112, Jonathan Rosand113, Jeffrey V. Rosenfeld114, Christina Rosenlund115, Guy Rosenthal55, Rolf Rossaint77, Sandra Rossi100, Daniel Rueckert61 Martin Rusnák116, Juan Sahuquillo105, Oliver Sakowitz90,117, Renan Sanchez-Porras117, Janos Sandor118, Nadine Schäfer81, Silke Schmidt119, Herbert Schoechl120, Guus Schoonman121, Rico Frederik Schou122, Elisabeth Schwendenwein6, Charlie Sewalt64, Ranjit D. Singh101, Toril Skandsen123,124, Peter Smielewski26, Abayomi Sorinola125, Emmanuel Stamatakis47, Simon Stanworth39, Robert Stevens126, William Stewart127, Ewout W. Steyerberg64,128, Nino Stocchetti129, Nina Sundström130, Riikka Takala131, Viktória Tamás125, Tomas Tamosuitis132, Mark Steven Taylor20, Braden Te Ao52, Olli Tenovuo103, Alice Theadom52, Matt Thomas87, Dick Tibboel133, Marjolein Timmers74, Christos Tolias134, Tony Trapani28, Cristina Maria Tudora93, Andreas Unterberg90, Peter Vajkoczy135, Shirley Vallance28, Egils Valeinis60, Zoltán Vámos50, Mathieu van der Jagt136, Gregory Van der Steen43, Joukje van der Naalt71, Jeroen T.J.M. van Dijck101, Inge A. van Erp101, Thomas A. van Essen101, Wim Van Hecke137, Caroline van Heugten138, Dominique Van Praag139, Ernest van Veen64, Thijs Vande Vyvere137, Roel P. J. van Wijk101, Alessia Vargiolu32, Emmanuel Vega83, Kimberley Velt64, Jan Verheyden137, Paul M. Vespa140, Anne Vik123,141, Rimantas Vilcinis132, Victor Volovici67, Nicole von Steinbüchel38, Daphne Voormolen64, Petar Vulekovic46, Kevin K.W. Wang142, Daniel Whitehouse47, Eveline Wiegers64, Guy Williams47, Lindsay Wilson69, Stefan Winzeck47, Stefan Wolf143, Zhihui Yang113, Peter Ylén144, Alexander Younsi90, Frederick A. Zeiler47,145, Veronika Zelinkova20, Agate Ziverte60, and Tommaso Zoerle27.

1Department of Physiology and Pharmacology, Section of Perioperative Medicine and Intensive Care, Karolinska Institutet, Stockholm, Sweden

2János Szentágothai Research Centre, University of Pécs, Pécs, Hungary

3Division of Surgery and Clinical Neuroscience, Department of Physical Medicine and Rehabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway

4Department of Neurosurgery, University Hospital Northern Norway, Tromso, Norway

5Department of Physical Medicine and Rehabilitation, University Hospital Northern Norway, Tromso, Norway

6Trauma Surgery, Medical University Vienna, Vienna, Austria

7Department of Anesthesiology & Intensive Care, University Hospital Nancy, Nancy, France

8Raymond Poincare hospital, Assistance Publique – Hopitaux de Paris, Paris, France

9Department of Anesthesiology & Intensive Care, S Raffaele University Hospital, Milan, Italy

10Department of Neurosurgery, Radboud University Medical Center, Nijmegen, The Netherlands

11Department of Neurosurgery, University of Szeged, Szeged, Hungary

12International Projects Management, ARTTIC, Munchen, Germany

13Department of Neurology, Neurological Intensive Care Unit, Medical University of Innsbruck, Innsbruck, Austria

14Department of Neurosurgery & Anesthesia & intensive care medicine, Karolinska University Hospital, Stockholm, Sweden

15NIHR Surgical Reconstruction and Microbiology Research Centre, Birmingham, UK

16Anesthesie-Réanimation, Assistance Publique – Hopitaux de Paris, Paris, France

17Department of Anesthesia & ICU, AOU Città della Salute e della Scienza di Torino - Orthopedic and Trauma Center, Torino, Italy

18Department of Neurology, Odense University Hospital, Odense, Denmark

19BehaviourWorks Australia, Monash Sustainability Institute, Monash University, Victoria, Australia

20Department of Public Health, Faculty of Health Sciences and Social Work, Trnava University, Trnava, Slovakia

21Quesgen Systems Inc., Burlingame, California, USA

22Australian & New Zealand Intensive Care Research Centre, Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia

23Department of Surgery and Perioperative Science, Umeå University, Umeå, Sweden

24Department of Neurosurgery, Medical School, University of Pécs, Hungary and Neurotrauma Research Group, János Szentágothai Research Centre, University of Pécs, Hungary

25Department of Medical Psychology, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany

26Brain Physics Lab, Division of Neurosurgery, Dept of Clinical Neurosciences, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK

27Neuro ICU, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy

28ANZIC Research Centre, Monash University, Department of Epidemiology and Preventive Medicine, Melbourne, Victoria, Australia

29Department of Neurosurgery, Hospital of Cruces, Bilbao, Spain

30NeuroIntensive Care, Niguarda Hospital, Milan, Italy

31School of Medicine and Surgery, Università Milano Bicocca, Milano, Italy

32NeuroIntensive Care, ASST di Monza, Monza, Italy

33Department of Neurosurgery, Medical Faculty RWTH Aachen University, Aachen, Germany

34Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany

35Department of Anesthesia & Neurointensive Care, Cambridge University Hospital NHS Foundation Trust, Cambridge, UK

36School of Public Health & PM, Monash University and The Alfred Hospital, Melbourne, Victoria, Australia

37Radiology/MRI department, MRC Cognition and Brain Sciences Unit, Cambridge, UK

38Institute of Medical Psychology and Medical Sociology, Universitätsmedizin Göttingen, Göttingen, Germany

39Oxford University Hospitals NHS Trust, Oxford, UK

40Intensive Care Unit, CHU Poitiers, Potiers, France

41University of Manchester NIHR Biomedical Research Centre, Critical Care Directorate, Salford Royal Hospital NHS Foundation Trust, Salford, UK

42Movement Science Group, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK

43Department of Neurosurgery, Antwerp University Hospital and University of Antwerp, Edegem, Belgium

44Department of Anesthesia & Intensive Care, Maggiore Della Carità Hospital, Novara, Italy

45Department of Neurosurgery, University Hospitals Leuven, Leuven, Belgium

46Department of Neurosurgery, Clinical centre of Vojvodina, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia

47Division of Anaesthesia, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK

48Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany

49Intensive Care Unit, CHR Citadelle, Liège, Belgium

50Department of Anaesthesiology and Intensive Therapy, University of Pécs, Pécs, Hungary

51Departments of Neurology, Clinical Neurophysiology and Neuroanesthesiology, Region Hovedstaden Rigshospitalet, Copenhagen, Denmark

52National Institute for Stroke and Applied Neurosciences, Faculty of Health and Environmental Studies, Auckland University of Technology, Auckland, New Zealand

53Department of Neurology, Erasmus MC, Rotterdam, the Netherlands

54Department of Anesthesiology and Intensive care, University Hospital Northern Norway, Tromso, Norway

55Department of Neurosurgery, Hadassah-hebrew University Medical center, Jerusalem, Israel

56Fundación Instituto Valenciano de Neurorrehabilitación (FIVAN), Valencia, Spain

57Department of Neurosurgery, Shanghai Renji hospital, Shanghai Jiaotong University/school of medicine, Shanghai, China

58Karolinska Institutet, INCF International Neuroinformatics Coordinating Facility, Stockholm, Sweden

59Emergency Department, CHU, Liège, Belgium

60Neurosurgery clinic, Pauls Stradins Clinical University Hospital, Riga, Latvia

61Department of Computing, Imperial College London, London, UK

62Department of Neurosurgery, Hospital Universitario 12 de Octubre, Madrid, Spain

63Department of Anesthesia, Critical Care and Pain Medicine, Medical University of Vienna, Austria

64Department of Public Health, Erasmus Medical Center-University Medical Center, Rotterdam, The Netherlands

65College of Health and Medicine, Australian National University, Canberra, Australia

66Department of Neurosurgery, Neurosciences Centre & JPN Apex trauma centre, All India Institute of Medical Sciences, New Delhi-110029, India

67Department of Neurosurgery, Erasmus MC, Rotterdam, the Netherlands

68Department of Neurosurgery, Oslo University Hospital, Oslo, Norway

69Division of Psychology, University of Stirling, Stirling, UK

70Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke’s Hospital & University of Cambridge, Cambridge, UK

71Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands

72Neurointensive Care, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK

73Salford Royal Hospital NHS Foundation Trust Acute Research Delivery Team, Salford, UK

74Department of Intensive Care and Department of Ethics and Philosophy of Medicine, Erasmus Medical Center, Rotterdam, The Netherlands

75Department of Clinical Neuroscience, Neurosurgery, Umeå University, Umeå, Sweden

76Hungarian Brain Research Program - Grant No. KTIA_13_NAP-A-II/8, University of Pécs, Pécs, Hungary

77Department of Anaesthesiology, University Hospital of Aachen, Aachen, Germany

78Cyclotron Research Center, University of Liège, Liège, Belgium

79Centre for Urgent and Emergency Care Research (CURE), Health Services Research Section, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK

80Emergency Department, Salford Royal Hospital, Salford UK

81Institute of Research in Operative Medicine (IFOM), Witten/Herdecke University, Cologne, Germany

82VP Global Project Management CNS, ICON, Paris, France

83Department of Anesthesiology-Intensive Care, Lille University Hospital, Lille, France

84Department of Neurosurgery, Rambam Medical Center, Haifa, Israel

85Department of Anesthesiology & Intensive Care, University Hospitals Southhampton NHS Trust, Southhampton, UK

86Cologne-Merheim Medical Center (CMMC), Department of Traumatology, Orthopedic Surgery and Sportmedicine, Witten/Herdecke University, Cologne, Germany

87Intensive Care Unit, Southmead Hospital, Bristol, Bristol, UK

88Department of Neurological Surgery, University of California, San Francisco, California, USA

89Department of Anesthesia & Intensive Care,M. Bufalini Hospital, Cesena, Italy

90Department of Neurosurgery, University Hospital Heidelberg, Heidelberg, Germany

91Department of Neurosurgery, The Walton centre NHS Foundation Trust, Liverpool, UK

92Department of Medical Genetics, University of Pécs, Pécs, Hungary

93Department of Neurosurgery, Emergency County Hospital Timisoara, Timisoara, Romania

94School of Medical Sciences, Örebro University, Örebro, Sweden

95Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland

96Analytic and Translational Genetics Unit, Department of Medicine; Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry; Department of Neurology, Massachusetts General Hospital, Boston, MA, USA

97Program in Medical and Population Genetics; The Stanley Center for Psychiatric Research, The Broad Institute of MIT and Harvard, Cambridge, MA, USA

98Department of Radiology, University of Antwerp, Edegem, Belgium

99Department of Anesthesiology & Intensive Care, University Hospital of Grenoble, Grenoble, France

100Department of Anesthesia & Intensive Care, Azienda Ospedaliera Università di Padova, Padova, Italy

101Dept. of Neurosurgery, Leiden University Medical Center, Leiden, The Netherlands and Dept. of Neurosurgery, Medical Center Haaglanden, The Hague, The Netherlands

102Department of Neurosurgery, Helsinki University Central Hospital

103Division of Clinical Neurosciences, Department of Neurosurgery and Turku Brain Injury Centre, Turku University Hospital and University of Turku, Turku, Finland

104Department of Anesthesiology and Critical Care, Pitié -Salpêtrière Teaching Hospital, Assistance Publique, Hôpitaux de Paris and University Pierre et Marie Curie, Paris, France

105Neurotraumatology and Neurosurgery Research Unit (UNINN), Vall d'Hebron Research Institute, Barcelona, Spain

106Department of Neurosurgery, Kaunas University of technology and Vilnius University, Vilnius, Lithuania

107Department of Neurosurgery, Rezekne Hospital, Latvia

108Department of Anaesthesia, Critical Care & Pain Medicine NHS Lothian & University of Edinburg, Edinburgh, UK

109Director, MRC Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, UK

110Department of Physical Medicine and Rehabilitation, Oslo University Hospital/University of Oslo, Oslo, Norway

111Division of Orthopedics, Oslo University Hospital, Oslo, Norway

112Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway

113Broad Institute, Cambridge MA Harvard Medical School, Boston MA, Massachusetts General Hospital, Boston MA, USA

114National Trauma Research Institute, The Alfred Hospital, Monash University, Melbourne, Victoria, Australia

115Department of Neurosurgery, Odense University Hospital, Odense, Denmark

116International Neurotrauma Research Organisation, Vienna, Austria

117Klinik für Neurochirurgie, Klinikum Ludwigsburg, Ludwigsburg, Germany

118Division of Biostatistics and Epidemiology, Department of Preventive Medicine, University of Debrecen, Debrecen, Hungary

119Department Health and Prevention, University Greifswald, Greifswald, Germany

120Department of Anaesthesiology and Intensive Care, AUVA Trauma Hospital, Salzburg, Austria

121Department of Neurology, Elisabeth-TweeSteden Ziekenhuis, Tilburg, the Netherlands

122Department of Neuroanesthesia and Neurointensive Care, Odense University Hospital, Odense, Denmark

123Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, NTNU, Trondheim, Norway

124Department of Physical Medicine and Rehabilitation, St.Olavs Hospital, Trondheim University Hospital, Trondheim, Norway

125Department of Neurosurgery, University of Pécs, Pécs, Hungary

126Division of Neuroscience Critical Care, John Hopkins University School of Medicine, Baltimore, USA

127Department of Neuropathology, Queen Elizabeth University Hospital and University of Glasgow, Glasgow, UK

128Dept. of Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, The Netherlands

129Department of Pathophysiology and Transplantation, Milan University, and Neuroscience ICU, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milano, Italy

130Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden

131Perioperative Services, Intensive Care Medicine and Pain Management, Turku University Hospital and University of Turku, Turku, Finland

132Department of Neurosurgery, Kaunas University of Health Sciences, Kaunas, Lithuania

133Intensive Care and Department of Pediatric Surgery, Erasmus Medical Center, Sophia Children’s Hospital, Rotterdam, The Netherlands

134Department of Neurosurgery, Kings college London, London, UK

135Neurologie, Neurochirurgie und Psychiatrie, Charité – Universitätsmedizin Berlin, Berlin, Germany

136Department of Intensive Care Adults, Erasmus MC– University Medical Center Rotterdam, Rotterdam, the Netherlands

137icoMetrix NV, Leuven, Belgium

138Movement Science Group, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK

139Psychology Department, Antwerp University Hospital, Edegem, Belgium

140Director of Neurocritical Care, University of California, Los Angeles, USA

141Department of Neurosurgery, St.Olavs Hospital, Trondheim University Hospital, Trondheim, Norway

142Department of Emergency Medicine, University of Florida, Gainesville, Florida, USA

143Department of Neurosurgery, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany

144VTT Technical Research Centre, Tampere, Finland

145Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada

Author contributions

HFL and IEC planned the study, IEC, JAH, and NVL wrote the article, and IEC analyzed the data. JAH and AIRM provided insight into clinic processes. AIRM and HFL provided valuable input in the writing process and expert knowledge. All authors revised and approved the final version of the manuscript.

Source of support

The authors’ work on this study is partly funded by the European Union seventh Framework Program (grant 602150) for Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI). Additional support for CENTER-TBI was obtained from the Hannelore Kohl Stiftung (Germany), OneMind (USA), Integra LifeSciences Corporation (USA), and NeuroTrauma Sciences (USA).

Availability of data and material

The datasets generated and/or analysed during the current study are not publicly available because participants gave no consent for data sharing. The datasets generated and/or analysed during the current study are not publicly available because participants gave no consent for data sharing.

Conflicts of interest

All authors are (partly) funded by the CENTER-TBI study, which is in essence a comparative effectiveness research study. Findings of this study concern the use of CENTER-TBI in comparative effectiveness research, which could be noted as competing interests.

We confirm that the manuscript complies with all instructions to authors and that authorship requirements have been met and the final manuscript was approved by all authors. Further we confirm that this manuscript has not been published elsewhere and is not under consideration by another journal

Ethical approval/informed consent

The CENTER-TBI study (EC grant 602150) has been conducted in accordance with all relevant laws of the EU if directly applicable or of direct effect and all relevant laws of the country where the recruiting sites were located, including but not limited to, the relevant privacy and data protection laws and regulations (the “Privacy Law”), the relevant laws and regulations on the use of human materials, and all relevant guidance relating to clinical studies from time to time in force including, but not limited to, the ICH Harmonised Tripartite Guideline for Good Clinical Practice (CPMP/ICH/135/95) (“ICH GCP”) and the World Medical Association Declaration of Helsinki entitled “Ethical Principles for Medical Research Involving Human Subjects.” Informed Consent by the patients and/or the legal representative/next of kin was obtained, accordingly to the local legislations, for all patients recruited in the Core Dataset of CENTER-TBI and documented in the e-CRF. Ethical approval was obtained for each recruiting sites. The list of sites, Ethical Committees, approval numbers and approval dates can be found here: https://www.center-tbi.eu/project/ethical-approval. The Center for Medical Decision Making, Department of Public Health, Erasmus MC as well as the Department of Neurosurgery, Antwerp University Hospital and University of Antwerp cooperated in the development and realization of the study, and therefore participating researchers had access to the data.

Footnotes

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Iris E. Ceyisakar, Email: iris.kohen@gmail.com

Jilske A. Huijben, Email: jhuijben@hotmail.com

Andrew I. R. Maas, Email: andrew.maas@uza.be

Hester F. Lingsma, Email: h.lingsma@erasmusmc.nl

Nikki van Leeuwen, Email: n.vanleeuwen.1@erasmusmc.nl.

CENTER-TBI participants and investigators:

Cecilia Åkerlund, Krisztina Amrein, Nada Andelic, Lasse Andreassen, Audny Anke, Anna Antoni, Gérard Audibert, Philippe Azouvi, Maria Luisa Azzolini, Ronald Bartels, Pál Barzó, Romuald Beauvais, Ronny Beer, Bo-Michael Bellander, Antonio Belli, Habib Benali, Maurizio Berardino, Luigi Beretta, Morten Blaabjerg, Peter Bragge, Alexandra Brazinova, Vibeke Brinck, Joanne Brooker, Camilla Brorsson, Andras Buki, Monika Bullinger, Manuel Cabeleira, Alessio Caccioppola, Emiliana Calappi, Maria Rosa Calvi, Peter Cameron, Guillermo Carbayo Lozano, Marco Carbonara, Simona Cavallo, Giorgio Chevallard, Arturo Chieregato, Giuseppe Citerio, Hans Clusmann, Mark Coburn, Jonathan Coles, Jamie D. Cooper, Marta Correia, Amra Čović, Nicola Curry, Endre Czeiter, Marek Czosnyka, Claire Dahyot-Fizelier, Paul Dark, Helen Dawes, Véronique De Keyser, Vincent Degos, Francesco Della Corte, Hugo den Boogert, Bart Depreitere, Đula Đilvesi, Abhishek Dixit, Emma Donoghue, Jens Dreier, Guy-Loup Dulière, Ari Ercole, Patrick Esser, Erzsébet Ezer, Martin Fabricius, Valery L. Feigin, Kelly Foks, Shirin Frisvold, Alex Furmanov, Pablo Gagliardo, Damien Galanaud, Dashiell Gantner, Guoyi Gao, Pradeep George, Alexandre Ghuysen, Lelde Giga, Ben Glocker, Jagoš Golubovic, Pedro A. Gomez, Johannes Gratz, Benjamin Gravesteijn, Francesca Grossi, Russell L. Gruen, Deepak Gupta, Juanita A. Haagsma, Iain Haitsma, Raimund Helbok, Eirik Helseth, Lindsay Horton, Jilske Huijben, Peter J. Hutchinson, Bram Jacobs, Stefan Jankowski, Mike Jarrett, Ji-yao Jiang, Faye Johnson, Kelly Jones, Mladen Karan, Angelos G. Kolias, Erwin Kompanje, Daniel Kondziella, Evgenios Kornaropoulos, Lars-Owe Koskinen, Noémi Kovács, Ana Kowark, Alfonso Lagares, Linda Lanyon, Steven Laureys, Fiona Lecky, Didier Ledoux, Rolf Lefering, Valerie Legrand, Aurelie Lejeune, Leon Levi, Roger Lightfoot, Hester Lingsma, Andrew I. R. Maas, Ana M. Castaño-León, Marc Maegele, Marek Majdan, Alex Manara, Geoffrey Manley, Costanza Martino, Hugues Maréchal, Julia Mattern, Catherine McMahon, Béla Melegh, David Menon, Tomas Menovsky, Ana Mikolic, Benoit Misset, Visakh Muraleedharan, Lynnette Murray, Ancuta Negru, David Nelson, Virginia Newcombe, Daan Nieboer, József Nyirádi, Otesile Olubukola, Matej Oresic, Fabrizio Ortolano, Aarno Palotie, Paul M. Parizel, Jean-François Payen, Natascha Perera, Vincent Perlbarg, Paolo Persona, Wilco Peul, Anna Piippo-Karjalainen, Matti Pirinen, Dana Pisica, Horia Ples, Suzanne Polinder, Inigo Pomposo, Jussi P. Posti, Louis Puybasset, Andreea Radoi, Arminas Ragauskas, Rahul Raj, Malinka Rambadagalla, Isabel Retel Helmrich, Jonathan Rhodes, Sylvia Richardson, Sophie Richter, Samuli Ripatti, Saulius Rocka, Cecilie Roe, Olav Roise, Jonathan Rosand, Jeffrey V. Rosenfeld, Christina Rosenlund, Guy Rosenthal, Rolf Rossaint, Sandra Rossi, Daniel Rueckert, Martin Rusnák, Juan Sahuquillo, Oliver Sakowitz, Renan Sanchez-Porras, Janos Sandor, Nadine Schäfer, Silke Schmidt, Herbert Schoechl, Guus Schoonman, Rico Frederik Schou, Elisabeth Schwendenwein, Charlie Sewalt, Ranjit D. Singh, Toril Skandsen, Peter Smielewski, Abayomi Sorinola, Emmanuel Stamatakis, Simon Stanworth, Robert Stevens, William Stewart, Ewout W. Steyerberg, Nino Stocchetti, Nina Sundström, Riikka Takala, Viktória Tamás, Tomas Tamosuitis, Mark Steven Taylor, Braden Te Ao, Olli Tenovuo, Alice Theadom, Matt Thomas, Dick Tibboel, Marjolein Timmers, Christos Tolias, Tony Trapani, Cristina Maria Tudora, Andreas Unterberg, Peter Vajkoczy, Shirley Vallance, Egils Valeinis, Zoltán Vámos, Mathieu van der Jagt, Gregory Van der Steen, Joukje van der Naalt, Jeroen T. J. M. van Dijck, Inge A. van Erp, Thomas A. van Essen, Wim Van Hecke, Caroline van Heugten, Dominique Van Praag, Ernest van Veen, Thijs Vande Vyvere, Roel P. J. van Wijk, Alessia Vargiolu, Emmanuel Vega, Kimberley Velt, Jan Verheyden, Paul M. Vespa, Anne Vik, Rimantas Vilcinis, Victor Volovici, Nicole von Steinbüchel, Daphne Voormolen, Petar Vulekovic, Kevin K. W. Wang, Daniel Whitehouse, Eveline Wiegers, Guy Williams, Lindsay Wilson, Stefan Winzeck, Stefan Wolf, Zhihui Yang, Peter Ylén, Alexander Younsi, Frederick A. Zeiler, Veronika Zelinkova, Agate Ziverte, and Tommaso Zoerle

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

12028_2021_1386_MOESM1_ESM.tiff (3.3MB, tiff)

Supplementary Figure 1. Correlation plot-showing correlations between questions, after questions have been grouped according to hierarchical clustering (TIFF 3344 KB)

12028_2021_1386_MOESM2_ESM.tiff (40MB, tiff)

Supplementary Figure 2. Heatmaps showing similarity between hospitals in answers given to question based on the hierarchical cluster analyses. The colors in the heatmap relate to the specific answers: within a column the same color indicates that two hospitals have given the same answer to the corresponding question (TIFF 40917 KB)

Supplementary file3 (DOCX 23 KB) (22.8KB, docx)

Data Availability Statement

The datasets generated and/or analysed during the current study are not publicly available because participants gave no consent for data sharing. The datasets generated and/or analysed during the current study are not publicly available because participants gave no consent for data sharing.

Articles from Neurocritical Care are provided here courtesy of Springer

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