Can We Cluster ICU Treatment Strategies for Traumatic Brain Injury by Hospital Treatment Preferences?
Authors: Ceyisakar Iris E. , Huijben Jilske A. , Maas Andrew I. R. , Lingsma Hester F. , van Leeuwen Nikki ,   CENTER-TBI participants and investigators, Åkerlund Cecilia , Amrein Krisztina , Andelic Nada , Andreassen Lasse , Anke Audny , Antoni Anna , Audibert Gérard , Azouvi Philippe , Azzolini Maria Luisa , Bartels Ronald , Barzó Pál , Beauvais Romuald , Beer Ronny , Bellander Bo-Michael , Belli Antonio , Benali Habib , Berardino Maurizio , Beretta Luigi , Blaabjerg Morten , Bragge Peter , Brazinova Alexandra , Brinck Vibeke , Brooker Joanne , Brorsson Camilla , Buki Andras , Bullinger Monika , Cabeleira Manuel , Caccioppola Alessio , Calappi Emiliana , Calvi Maria Rosa , Cameron Peter , Lozano Guillermo Carbayo , Carbonara Marco , Cavallo Simona , Chevallard Giorgio , Chieregato Arturo , Citerio Giuseppe , Clusmann Hans , Coburn Mark , Coles Jonathan , Cooper Jamie D. , Correia Marta , Čović Amra , Curry Nicola , Czeiter Endre , Czosnyka Marek , Dahyot-Fizelier Claire , Dark Paul , Dawes Helen , De Keyser Véronique , Degos Vincent , Corte Francesco Della , Boogert Hugo den , Depreitere Bart , Đilvesi Đula , Dixit Abhishek , Donoghue Emma , Dreier Jens , Dulière Guy-Loup , Ercole Ari , Esser Patrick , Ezer Erzsébet , Fabricius Martin , Feigin Valery L. , Foks Kelly , Frisvold Shirin , Furmanov Alex , Gagliardo Pablo , Galanaud Damien , Gantner Dashiell , Gao Guoyi , George Pradeep , Ghuysen Alexandre , Giga Lelde , Glocker Ben , Golubovic Jagoš , Gomez Pedro A. , Gratz Johannes , Gravesteijn Benjamin , Grossi Francesca , Gruen Russell L. , Gupta Deepak , Haagsma Juanita A. , Haitsma Iain , Helbok Raimund , Helseth Eirik , Horton Lindsay , Huijben Jilske , Hutchinson Peter J. , Jacobs Bram , Jankowski Stefan , Jarrett Mike , Jiang Ji-yao , Johnson Faye , Jones Kelly , Karan Mladen , Kolias Angelos G. , Kompanje Erwin , Kondziella Daniel , Kornaropoulos Evgenios , Koskinen Lars-Owe , Kovács Noémi , Kowark Ana , Lagares Alfonso , Lanyon Linda , Laureys Steven , Lecky Fiona , Ledoux Didier , Lefering Rolf , Legrand Valerie , Lejeune Aurelie , Levi Leon , Lightfoot Roger , Lingsma Hester , Maas Andrew I. R. , Castaño-León Ana M. , Maegele Marc , Majdan Marek , Manara Alex , Manley Geoffrey , Martino Costanza , Maréchal Hugues , Mattern Julia , McMahon Catherine , Melegh Béla , Menon David , Menovsky Tomas , Mikolic Ana , Misset Benoit , Muraleedharan Visakh , Murray Lynnette , Negru Ancuta , Nelson David , Newcombe Virginia , Nieboer Daan , Nyirádi József , Olubukola Otesile , Oresic Matej , Ortolano Fabrizio , Palotie Aarno , Parizel Paul M. , Payen Jean-François , Perera Natascha , Perlbarg Vincent , Persona Paolo , Peul Wilco , Piippo-Karjalainen Anna , Pirinen Matti , Pisica Dana , Ples Horia , Polinder Suzanne , Pomposo Inigo , Posti Jussi P. , Puybasset Louis , Radoi Andreea , Ragauskas Arminas , Raj Rahul , Rambadagalla Malinka , Helmrich Isabel Retel , Rhodes Jonathan , Richardson Sylvia , Richter Sophie , Ripatti Samuli , Rocka Saulius , Roe Cecilie , Roise Olav , Rosand Jonathan , Rosenfeld Jeffrey V. , Rosenlund Christina , Rosenthal Guy , Rossaint Rolf , Rossi Sandra , Rueckert Daniel , Rusnák Martin , Sahuquillo Juan , Sakowitz Oliver , Sanchez-Porras Renan , Sandor Janos , Schäfer Nadine , Schmidt Silke , Schoechl Herbert , Schoonman Guus , Schou Rico Frederik , Schwendenwein Elisabeth , Sewalt Charlie , Singh Ranjit D. , Skandsen Toril , Smielewski Peter , Sorinola Abayomi , Stamatakis Emmanuel , Stanworth Simon , Stevens Robert , Stewart William , Steyerberg Ewout W. , Stocchetti Nino , Sundström Nina , Takala Riikka , Tamás Viktória , Tamosuitis Tomas , Taylor Mark Steven , Ao Braden Te , Tenovuo Olli , Theadom Alice , Thomas Matt , Tibboel Dick , Timmers Marjolein , Tolias Christos , Trapani Tony , Tudora Cristina Maria , Unterberg Andreas , Vajkoczy Peter , Vallance Shirley , Valeinis Egils , Vámos Zoltán , van der Jagt Mathieu , Van der Steen Gregory , van der Naalt Joukje , van Dijck Jeroen T. J. M. , van Erp Inge A. , van Essen Thomas A. , Van Hecke Wim , van Heugten Caroline , Van Praag Dominique , van Veen Ernest , Vyvere Thijs Vande , van Wijk Roel P. J. , Vargiolu Alessia , Vega Emmanuel , Velt Kimberley , Verheyden Jan , Vespa Paul M. , Vik Anne , Vilcinis Rimantas , Volovici Victor , von Steinbüchel Nicole , Voormolen Daphne , Vulekovic Petar , Wang Kevin K. W. , Whitehouse Daniel , Wiegers Eveline , Williams Guy , Wilson Lindsay , Winzeck Stefan , Wolf Stefan , Yang Zhihui , Ylén Peter , Younsi Alexander , Zeiler Frederick A. , Zelinkova Veronika , Ziverte Agate , Zoerle Tommaso 
Published: December 2021

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.