ORCID Profile
0000-0002-8412-622X
Current Organisations
University of Zurich
,
University Medical Center Groningen
,
Radboud Universiteit
,
Universität Zürich
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Publisher: Mary Ann Liebert Inc
Date: 07-2021
Abstract: In medical research, missing data is common. In acute diseases, such as traumatic brain injury (TBI), even well-conducted prospective studies may suffer from missing data in baseline characteristics and outcomes. Statistical models may simply drop patients with any missing values, potentially leaving a selected subset of the original cohort. Imputation is widely accepted by methodologists as an appropriate way to deal with missing data. We aim to provide practical guidance on handling missing data for prediction modeling. We hereto propose a five-step approach, centered around single and multiple imputation: 1) explore the missing data patterns 2) choose a method of imputation 3) perform imputation 4) assess diagnostics of the imputation and 5) analyze the imputed data sets. We illustrate these five steps with the estimation and validation of the IMPACT (International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury) prognostic model in 1375 patients from the CENTER-TBI database, included in 53 centers across 17 countries, with moderate or severe TBI in the prospective European CENTER-TBI study. Future prediction modeling studies in acute diseases may benefit from following the suggested five steps for optimal statistical analysis and interpretation, after maximal effort has been made to minimize missing data.
Publisher: Springer Science and Business Media LLC
Date: 05-08-2021
Publisher: Proceedings of the National Academy of Sciences
Date: 30-05-2023
Abstract: Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity—variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to s ling variance. We find substantial design heterogeneity—estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs—indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.INJURY.2012.05.020
Abstract: Prehospital care by physician-based helicopter emergency medical services (P-HEMS) may prolong total prehospital run time. This has raised an issue of debate about the benefits of these services in traumatic brain injury (TBI). We therefore investigated the effects of P-HEMS dispatch on prehospital run time and outcome in severe TBI. Prehospital run times of 497 patients with severe TBI who were solely treated by a paramedic EMS (n = 125) or an EMS/P-HEMS combination (n = 372) were retrospectively analyzed. Other study parameters included the injury severity score (ISS), Glasgow Coma Scale (GCS), prehospital endotracheal intubation and predicted and observed outcome rates. Patients who received P-HEMS care were younger and had higher ISS values than solely EMS-treated patients (10% P = 0.04). The overall prehospital run time was 74 ± 54 min, with similar out-of-hospital times for EMS and P-HEMS treated patients. Prehospital endotracheal intubation was more frequently performed in the P-HEMS group (88%) than in the EMS group (35% P<0.001). The prehospital run time for intubated patients was similar for P-HEMS (66 (51-80)min) and EMS-treated patients (59 (41-88 min). Unexpectedly, mortality probability scores and observed outcome scores were less favourable for EMS-treated patients when compared to patients treated by P-HEMS. P-HEMS dispatch does not increase prehospital run times in severe TBI, while it assures prehospital intubation of TBI patients by a well-trained physician. Our data however suggest that a subgroup of the most severely injured patients received prehospital care by an EMS, while international guidelines recommend advanced life support by a physician-based EMS in these cases.
Publisher: Mary Ann Liebert Inc
Date: 15-05-2021
Abstract: The International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) and Corticoid Randomisation After Significant Head injury (CRASH) prognostic models predict functional outcome after moderate and severe traumatic brain injury (TBI). We aimed to assess their performance in a contemporary cohort of patients across Europe. The Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) core study is a prospective, observational cohort study in patients presenting with TBI and an indication for brain computed tomography. The CENTER-TBI core cohort consists of 4509 TBI patients available for analyses from 59 centers in 18 countries across Europe and Israel. The IMPACT validation cohort included 1173 patients with GCS ≤12, age ≥14, and 6-month Glasgow Outcome Scale-Extended (GOSE) available. The CRASH validation cohort contained 1742 patients with GCS ≤14, age ≥16, and 14-day mortality or 6-month GOSE available. Performance of the three IMPACT and two CRASH model variants was assessed with discrimination (area under the receiver operating characteristic curve AUC) and calibration (comparison of observed vs. predicted outcome rates). For IMPACT, model discrimination was good, with AUCs ranging between 0.77 and 0.85 in 1173 patients and between 0.80 and 0.88 in the broader CRASH selection (
Publisher: American Medical Association (AMA)
Date: 03-2021
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 16-11-2018
Publisher: Springer Science and Business Media LLC
Date: 21-03-2014
DOI: 10.1186/S13049-021-00930-1
Abstract: Prehospital care for patients with traumatic brain injury (TBI) varies with some emergency medical systems recommending direct transport of patients with moderate to severe TBI to hospitals with specialist neurotrauma care (SNCs). The aim of this study is to assess variation in levels of early secondary referral within European SNCs and to compare the outcomes of directly admitted and secondarily transferred patients. Patients with moderate and severe TBI (Glasgow Coma Scale 13) from the prospective European CENTER-TBI study were included in this study. All participating hospitals were specialist neuroscience centers. First, adjusted between-country differences were analysed using random effects logistic regression where early secondary referral was the dependent variable, and a random intercept for country was included. Second, the adjusted effect of early secondary referral on survival to hospital discharge and functional outcome [6 months Glasgow Outcome Scale Extended (GOSE)] was estimated using logistic and ordinal mixed effects models, respectively. A total of 1347 moderate/severe TBI patients from 53 SNCs in 18 European countries were included. Of these 1347 patients, 195 (14.5%) were admitted after early secondary referral. Secondarily referred moderate/severe TBI patients presented more often with a CT abnormality: mass lesion (52% vs. 34%), midline shift (54% vs. 36%) and acute subdural hematoma (77% vs. 65%). After adjusting for case-mix, there was a large European variation in early secondary referral, with a median OR of 1.69 between countries. Early secondary referral was not associated with functional outcome (adjusted OR 1.07, 95% CI 0.78–1.69), nor with survival at discharge (1.05, 0.58–1.90). Across Europe, substantial practice variation exists in the proportion of secondarily referred TBI patients at SNCs that is not explained by case mix. Within SNCs early secondary referral does not seem to impact functional outcome and survival after stabilisation in a non-specialised hospital. Future research should identify which patients with TBI truly benefit from direct transportation.
Publisher: Springer Science and Business Media LLC
Date: 10-09-2020
DOI: 10.1007/S00415-020-10174-1
Abstract: The original version of this article unfortunately contained a mistake.
Publisher: American Medical Association (AMA)
Date: 09-2021
Publisher: Springer Science and Business Media LLC
Date: 14-10-2017
Publisher: Springer Science and Business Media LLC
Date: 06-09-2017
Publisher: Informa UK Limited
Date: 03-11-2020
Publisher: Informa UK Limited
Date: 17-10-2020
DOI: 10.1080/09638288.2020.1832589
Abstract: There is conflicting literature on the effect of post- utation pain on quality of life (QOL) and no available literature on the relationship of pain medications to QOL of utees in pain. The aims of the study were to compare QOL in lower limb utees with significant pain to those with minimal pain and compare QOL in utees on multiple pain medications (≥3 and/or ≥ 40 mg morphine equivalent/day) to those on minimal. Cross-sectional study of utees ( Post- utation pain was common (69%), but only 13% of the participants were using more pain medications. High-pain interference and poor self-efficacy were associated with poorer QOL after adjusting for age, gender and cause of utation. High medication use was associated with high-pain interference and poor self-efficacy, but there was minimal correlation between pain scores and medication usage ( Post- utation pain continues to be a major determinant of QOL in lower limb utees, but the role of pain medications on an utee's QOL remains unclear.IMPLICATIONS FOR REHABILITATIONAn utee's QOL is affected by the severity of their post- utation pain even beyond six months post their utation.An utee with more pain may not necessarily take more pain medications to manage their pain. The amount of pain medications taken may not influence their self-reported QOL.Pain and QOL assessment should be integrated into routine clinical evaluation of adult utees. Standardized screening tools and/or formative assessment can be utilized for assessing QOL.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: Springer Science and Business Media LLC
Date: 24-07-2021
Publisher: Informa UK Limited
Date: 27-03-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-11-2020
Publisher: SAGE Publications
Date: 07-08-2020
Abstract: Although rehabilitation is beneficial for in iduals with traumatic brain injury (TBI), a significant proportion of them do not receive adequate rehabilitation after acute care. Therefore, the goal of this prospective and multicenter study was to investigate predictors of access to rehabilitation in the year following injury in patients with TBI. Data from a large European study (CENTER-TBI), including TBIs of all severities between December 2014 and December 2017 were used (N = 4498 patients). Participants were dichotomized into those who had and those who did not have access to rehabilitation in the year following TBI. Potential predictors included sociodemographic factors, psychoactive substance use, preinjury medical history, injury-related factors, and factors related to medical care, complications, and discharge. In the year following traumatic injury, 31.4% of patients received rehabilitation services. Access to rehabilitation was positively and significantly predicted by female sex (odds ratio [OR] = 1.50), increased number of years of education completed (OR = 1.05), living in Northern (OR = 1.62 reference: Western Europe) or Southern Europe (OR = 1.74), lower prehospital Glasgow Coma Scale score (OR = 1.03), higher Injury Severity Score (OR = 1.01), intracranial (OR = 1.33) and extracranial (OR = 1.99) surgery, and extracranial complication (OR = 1.75). On contrast, significant negative predictors were lack of preinjury employment (OR = 0.80), living in Central and Eastern Europe (OR = 0.42), and admission to hospital ward (OR = 0.47 reference: admission to intensive care unit) or direct discharge from emergency room (OR = 0.24). Based on these findings, there is an urgent need to implement national and international guidelines and strategies for access to rehabilitation after TBI.
Publisher: Mary Ann Liebert Inc
Date: 19-10-2020
Publisher: Springer Science and Business Media LLC
Date: 11-12-2020
DOI: 10.1007/S12028-020-01151-7
Abstract: Trauma-induced coagulopathy in patients with traumatic brain injury (TBI) is associated with high rates of complications, unfavourable outcomes and mortality. The mechanism of the development of TBI-associated coagulopathy is poorly understood. This analysis, embedded in the prospective, multi-centred, observational Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study, aimed to characterise the coagulopathy of TBI. Emphasis was placed on the acute phase following TBI, primary on subgroups of patients with abnormal coagulation profile within 4 h of admission, and the impact of pre-injury anticoagulant and/or antiplatelet therapy. In order to minimise confounding factors, patients with isolated TBI (iTBI) ( n = 598) were selected for this analysis. Haemostatic disorders were observed in approximately 20% of iTBI patients. In a subgroup analysis, patients with pre-injury anticoagulant and/or antiplatelet therapy had a twice exacerbated coagulation profile as likely as those without premedication. This was in turn associated with increased rates of mortality and unfavourable outcome post-injury. A multivariate analysis of iTBI patients without pre-injury anticoagulant therapy identified several independent risk factors for coagulopathy which were present at hospital admission. Glasgow Coma Scale (GCS) less than or equal to 8, base excess (BE) less than or equal to − 6, hypothermia and hypotension increased risk significantly. Consideration of these factors enables early prediction and risk stratification of acute coagulopathy after TBI, thus guiding clinical management.
Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
Date: 05-2021
Abstract: The aim of this paper was to evaluate the prevalence of postconcussive symptoms and their relation to health-related quality of life (HRQOL) in pediatric and adolescent patients with mild traumatic brain injury (mTBI) who received head CT imaging during initial assessment. Patients aged between 5 and 21 years with mTBI (Glasgow Coma Scale scores 13–15) and available Rivermead Post Concussion Questionnaire (RPQ) at 6 months of follow-up in the multicenter, prospectively collected CENTER-TBI (Collaborative European NeuroTrauma Effectiveness Research in TBI) study were included. The prevalence of postconcussive symptoms was assessed, and the occurrence of postconcussive syndrome (PSC) based on the ICD-10 criteria, was analyzed. HRQOL was compared in patients with and without PCS using the Quality of Life after Brain Injury (QOLIBRI) questionnaire. A total of 196 adolescent or pediatric mTBI patients requiring head CT imaging were included. High-energy trauma was prevalent in more than half of cases (54%), abnormalities on head CT scans were detected in 41%, and admission to the regular ward or intensive care unit was necessary in 78%. Six months postinjury, 36% of included patients had experienced at least one moderate or severe symptom on the RPQ. PCS was present in 13% of adolescents and children when considering symptoms of at least moderate severity, and those patients had significantly lower QOLIBRI total scores, indicating lower HRQOL, compared with young patients without PCS (57 vs 83 points, p 0.001). Adolescent and pediatric mTBI patients requiring head CT imaging show signs of increased trauma severity. Postconcussive symptoms are present in up to one-third of those patients, and PCS can be diagnosed in 13% 6 months after injury. Moreover, PCS is significantly associated with decreased HRQOL.
No related grants have been discovered for Stefan Zeisberger.