Search results for "ROC CURVE"
showing 10 items of 291 documents
Prediction of bleeding events in patients with venous thromboembolism on stable anticoagulation treatment.
2016
Attempts at identifying patients with an elevated risk of bleeding while on anticoagulation following acute venous thromboembolism (VTE) have largely been unsuccessful thus far. We sought to develop a clinical prediction score for bleeding during stable anticoagulation treatment after acute VTE.We performed a post hoc analysis of the pooled RE-COVER studies, two double-blind randomised “sister” trials evaluating dabigatran versus standard treatment in 5107 VTE patients.A score was derived from patients randomised to dabigatran using logistic regression analysis covering the complete follow-up period. The final model, named VTE-BLEED, included six variables and yielded a c-statistic of 0.72 …
Validation and update of the thoracic surgery scoring system (Thoracoscore) risk model.
2020
Abstract OBJECTIVES The performance of prediction models tends to deteriorate over time. The purpose of this study was to update the Thoracoscore risk prediction model with recent data from the Epithor nationwide thoracic surgery database. METHODS From January 2016 to December 2017, a total of 56 279 patients were operated on for mediastinal, pleural, chest wall or lung disease. We used 3 recommended methods to update the Thoracoscore prediction model and then proceeded to develop a new risk model. Thirty-day hospital mortality included patients who died within the first 30 days of the operation and those who died later during the same hospital stay. RESULTS We compared the baseline patient…
Prognostic Value of the 6-Min Walk Test After Open-Heart Valve Surgery: EXPERIENCE OF A CARDIOVASCULAR REHABILITATION PROGRAM
2018
PURPOSE: This single-center retrospective analysis aimed to evaluate the prognostic relevance of 6-min walk test (6MWT) in patients admitted to an in-hospital cardiovascular rehabilitation program after open-heart valve surgery. METHODS: One hundred one patients able to perform a 6MWT within the first week of admission (time after surgery: 16 ± 8 d) were included (age 68 ± 11 y; 55% female; median left ventricular ejection fraction 55% [interquartile range: 50-60]; 51% after aortic valve surgery). Study endpoints were cardiovascular death and the combined outcome of cardiovascular death/cardiac hospitalization. Univariate and multivariate analyses were performed to analyze predictive value …
Patterns and diagnostic value of cardiac troponin I vs. troponin T and CKMB after OPCAB surgery.
2001
Cardiac troponin I (cTnI) has been shown to be a specific marker for myocardial injury in cardiac surgery. The object of this prospective study was to determine the patterns and kinetic and diagnostic value of cTnI, cardiac troponin T (cTnT), and creatine kinase MB (CKMB) activity after minimally invasive coronary revascularization using an octopus device on the beating heart (OPCAB).48 patients (33 male/15 female, mean age 68.3 +/- 8.7 years) underwent their first elective OPCAB surgery with median sternotomy without mortality. The mean number of grafts was 2.0 +/- 0.8 per patient. Preoperative mean ejection fraction was 56.6 % +/- 14.9%. CTnI and T levels, total creatine kinase (CK) and C…
Prognostic impact of copeptin in pulmonary embolism: a multicentre validation study.
2018
To externally validate the prognostic impact of copeptin, either alone or integrated in risk stratification models, in pulmonary embolism (PE), we performed a post hoc analysis of 843 normotensive PE patients prospectively included in three European cohorts.Within the first 30 days, 21 patients (2.5%, 95% CI 1.5–3.8) had an adverse outcome and 12 (1.4%, 95% CI 0.7–2.5) died due to PE. Patients with copeptin ≥24 pmol·L−1 had a 6.3-fold increased risk for an adverse outcome (95% CI 2.6–15.5, p<0.001) and a 7.6-fold increased risk for PE-related death (95% CI 2.3–25.6, p=0.001). Risk classification according to the 2014 European Society of Cardiology (ESC) guideline algorithm identified 248…
In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: A receiver operating characteristic analysis
2005
Objective To compare experimentally the image quality of charged-coupled device (CCD)-based digital, flatbed scanner digitized, and dental film radiographs. Study design High-contrast standardized radiographs of an aluminum step wedge containing boreholes were obtained on dental radiographic film (F) and a CCD receptor (D). Digitization (S) was done with a flatbed scanner. Each radiograph was separated into 23 single images, 18 of which showed a dark spot. Thirty observers indicated their confidence on the visibility of the spots for a receiver operating characteristic (ROC) analysis. Results Mean Az values (area beneath the ROC curves) differed significantly (P < .05), being highest for D …
Optic disc positioning and blood vessels extraction on eye fundus
2009
This paper presents two methods aimed to the optic disc positioning on the retinal images. The first is based on a template of the entire image, while the second is based on the retinal vascularisation. For this second task, also a vessel extraction method is provided. Both the algorithm have been tested on test images of the Drive Database.
Probabilité d'apparition d'un phénomène parasitaire et choix de modèles de régression logistique
2007
Epidemiological processes are now using spatial statistics and modelling tools. The main objective of most health risks studies consists in identifying potential contamination sources and factors capable of explaining their localization. Health data often prove binary (typically presence/absence) and specific methods such as binary logistic regression have to be used. This method's output consists in a probability for the pathogen of interest. A posterior classification of each sample is then conducted using a probability threshold. The method used to maximize this threshold is called the ROC curve which consists in giving a representation of the behaviour of the model and then to choose th…
Weighted distance-based trees for ranking data
2017
Within the framework of preference rankings, the interest can lie in finding which predictors and which interactions are able to explain the observed preference structures, because preference decisions will usually depend on the characteristics of both the judges and the objects being judged. This work proposes the use of a univariate decision tree for ranking data based on the weighted distances for complete and incomplete rankings, and considers the area under the ROC curve both for pruning and model assessment. Two real and well-known datasets, the SUSHI preference data and the University ranking data, are used to display the performance of the methodology.
Definition of tachycardia for risk stratification of pulmonary embolism
2020
Tachycardia is a reliable predictor of adverse outcomes in normotensive patients with acute pulmonary embolism (PE). However, different prognostic relevant heart rate thresholds have been proposed. The aim of the study was to investigate the prognostic performance of different thresholds used for defining tachycardia in normotensive PE patients.We performed a post-hoc analysis of normotensive patients with confirmed PE consecutively included in a single-centre and a multi-centre registry. An adverse outcome was defined as PE-related death, need for mechanical ventilation, cardiopulmonary resuscitation or administration of catecholamines.Of 1567 patients (median age: 72 [IQR, 59-79] years; f…