Gera, Roland Gerard

[["dc.bibliographiccitation.firstpage","1879"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Statistical Methods in Medical Research"],["dc.bibliographiccitation.lastpage","1892"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Graf, Alexandra Christine"],["dc.contributor.author","Wassmer, Gernot"],["dc.contributor.author","Friede, Tim"],["dc.contributor.author","Gera, Roland Gerard"],["dc.contributor.author","Posch, Martin"],["dc.date.accessioned","2019-07-09T11:51:55Z"],["dc.date.available","2019-07-09T11:51:55Z"],["dc.date.issued","2018"],["dc.description.abstract","With the advent of personalized medicine, clinical trials studying treatment effects in subpopulations are receiving increasing attention. The objectives of such studies are, besides demonstrating a treatment effect in the overall population, to identify subpopulations, based on biomarkers, where the treatment has a beneficial effect. Continuous biomarkers are often dichotomized using a threshold to define two subpopulations with low and high biomarker levels. If there is insufficient information on the dependence structure of the outcome on the biomarker, several thresholds may be investigated. The nested structure of such subpopulations is similar to the structure in group sequential trials. Therefore, it has been proposed to use the corresponding critical boundaries to test such nested subpopulations. We show that for biomarkers with a prognostic effect that is not adjusted for in the statistical model, the variability of the outcome may vary across subpopulations which may lead to an inflation of the family-wise type 1 error rate. Using simulations we quantify the potential inflation of testing procedures based on group sequential designs. Furthermore, alternative hypotheses tests that control the family-wise type 1 error rate under minimal assumptions are proposed. The methodological approaches are illustrated by a trial in depression."],["dc.identifier.doi","10.1177/0962280218777538"],["dc.identifier.pmid","29888651"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16230"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60042"],["dc.notes.intern","Merged from goescholar"],["dc.relation","info:eu-repo/grantAgreement/EC/FP7/602144/EU//INSPIRE"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","610"],["dc.title","Robustness of testing procedures for confirmatory subpopulation analyses based on a continuous biomarker"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e0210334"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","PLOS ONE"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Behme, Daniel"],["dc.contributor.author","Tsogkas, Ioannis"],["dc.contributor.author","Colla, Ruben"],["dc.contributor.author","Gera, Roland G."],["dc.contributor.author","Schregel, Katharina"],["dc.contributor.author","Hesse, Amélie C."],["dc.contributor.author","Maier, Ilko L."],["dc.contributor.author","Liman, Jan"],["dc.contributor.author","Liebeskind, David S."],["dc.contributor.author","Psychogios, Marios-Nikos"],["dc.date.accessioned","2019-07-09T11:50:09Z"],["dc.date.available","2019-07-09T11:50:09Z"],["dc.date.issued","2019"],["dc.description.abstract","BACKGROUND: A thrombolysis in cerebral infarction (TICI) score of 2b is defined as a good recanalization result although the reperfusion may only cover 50% of the affected territory. An additional mTICI2c category was introduced to further differentiate between mTICI scores. Despite the new mTICI2c category, mTICI2b still covers a range of 50-90% reperfusion which might be too imprecise to predict neurological improvement after therapy. AIM: To compare the 7-point \"expanded TICI\" (eTICI) scale with the traditional mTICI in regard to predict functional independence at 90 days. METHODS: Retrospective review of 225 patients with large artery occlusion. Angiograms were graded by 2 readers according the 7-point eTICI score (0% = eTICI0; reduced clot = eTICI1; 1-49% = eTICI2a, 50-66% = eTICI2b50; 67-89% = eTICI2b67, 90-99% = eTICI2c and complete reperfusion = eTICI3) and the conventional mTICI score. The ability of e- and mTICI to predict favorable outcome at 90days was compared. RESULTS: Given the ROC analysis eTICI was the better predictor of favorable outcome (p-value 0.047). Additionally, eTICI scores 2b50, 2b67 and 2c (former mTICI2b) were significantly superior at predicting the probability of a favorable outcome at 90 days after endovascular therapy with a p-value of 0.033 (probabilities of 17% for mTICI2b50, 24% for mTICI2b67 and 54% for mTICI2c vs. 36% for mTICI2b). CONCLUSIONS: The 7-point eTICI allows for a more accurate outcome prediction compared to the mTICI score because it refines the broad range of former mTICI2b results."],["dc.identifier.doi","10.1371/journal.pone.0210334"],["dc.identifier.pmid","30629664"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15873"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59714"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","610"],["dc.title","Validation of the extended thrombolysis in cerebral infarction score in a real world cohort"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]