Track topics on Twitter Track topics that are important to you
Established approaches for analyzing meta-analyses of diagnostic accuracy model the bivariate distribution of the observed pairs of specificity Sp and sensitivity Se, thus accounting for across-study correlation. However, it is still a matter of debate how to define a summary ROC (SROC) curve. It was recently pointed out that the SROC curve is in principle unidentifiable if only one (Sp, Se) pair per study is known. We evaluate an alternative approach, modeling the study-specific ROC curves based on the assumption of linearity in logit space. A setting is considered in which the pair (Sp, Se) that is selected for publication in a particular study maximizes a weighted Youden index λSe+(1-λ)Sp with a given weight λ.This leads to a fixed slope (1-λ)/λ of the ROC curve in (1-Sp, Se), equivalent to a slope of (1-λ)Sp(1-Sp)/(λSe(1-Se)) for the corresponding straight line in logit space. While the slope depends on the variance ratio of the underlying distributions, the intercept is a function of the mean difference. Our approach leads in a natural way to a new, model-based proposal for a summary ROC curve. It is illustrated using an example from the literature. Copyright © 2010 John Wiley & Sons, Ltd.
Institute of Medical Biometry and Medical Informatics, University Medical Center, Freiburg, Germany; German Cochrane Centre, University Medical Center, Freiburg, Germany. firstname.lastname@example.org.
This article was published in the following journal.
Name: Statistics in medicine
The Youden Index is a summary measurement of the receiver operating characteristic (ROC) curve for the accuracy of a diagnostic test with ordinal or continuous endpoints. The bootstrap confidence inte...
The three-class approach is used for progressive disorders when clinicians and researchers want to diagnose or classify subjects as members of one of three ordered categories based on a continuous dia...
OBJECTIVE. The purpose of this study was to determine an optimal multiparametric MRI protocol for characterizing tumors of low versus high grade and differentiating tumors as T1 versus T2 for preopera...
A regularly spiking neuron can be studied using a phase model. The effect of an input stimulus current on the phase time derivative is captured by a phase response curve. This paper adapts a technique...
Procalcitonin (PCT) has been widely investigated for its prognostic value in septic patients. However, studies have produced conflicting results. The purpose of the present meta-analysis is to explore...
The smart capnography respiratory index is a software tool that constitutes a representation of 4 parameters: End Tidal CO2, respiratory rate, O2 saturation and heart rate already displaye...
The purpose of this study is to determine the dose-response curve for the MRI-based efficacy of BAF312 compared with placebo in patients with Relapsing-Remitting Multiple Sclerosis (RRMS),...
Primary endpoint: Defining The optimal target range for Surgical Pleth index. Surgical Pleth Index (SPI, formerly used SSI = Surgical Stress Index) is a novel multivariate index, which is ...
This pilot clinical trial studies how well diffusion-weighted magnetic resonance imaging (MRI) works in staging patients with prostate cancer that has not spread to nearby lymph nodes or o...
This study is designed to determine if adding daily weighted braces on the unaffected ankle may benefit to patient who have returned home compare to a placebo intervention (ankle brace wit...
The selecting and organizing of visual stimuli based on the individual's past experience.
A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies. (From Winslade, Dictionary of Clinical Research, 1992)
A combination of the debris index and the dental calculus index to determine the status of oral hygiene.
A sulfonic acid-based naphthylazo dye used as a coloring agent for foodstuffs and medicines and as a dye and chemical indicator. It was banned by the FDA in 1976 for use in foods, drugs, and cosmetics. (From Merck Index, 11th ed)
Cognitive mechanism based on expectations or beliefs about one's ability to perform actions necessary to produce a given effect. It is also a theoretical component of behavior change in various therapeutic treatments. (APA, Thesaurus of Psychological Index Terms, 1994)