Werner Vach, Rene Depont Christensen, Ole Mogensen, Anne Kjærgaard Callesen, Ole Nørregaard Jensen, Jonna Skov Madsen, ...
detection in mass spectrometry data using repeated
Diagnosis and treatment of musculoskeletal chest pain: design of a multi-purpose trial (2008)
Stochkendahl, Mette J, Christensen, Henrik W, Vach, Werner, Høilund-Carlsen, Poul, Haghfelt, Torben, Hartvigsen, Jan
Abstract Background Acute chest pain is a major health problem all over the western world. Active approaches are directed towards diagnosis and treatment of potentially life threatening conditions,...
On the Relation Between the Shrinkage Effect and a Shrinkage Method (2007)
this paper to explain the source of this shrinkage effect, to investigate its behaviour and to show that the shrinkage method proposed by van Houwelingen and le Cessie (1990) is just tailored to...
Shrinkage, Cross Validation Calibration, and the Construction of Prognostic Indices (2007)
this paper we focus on prediction, i.e. we want to predict an outcome variable
Missing Values in Epidemiological Studies (2007)
this paper we restrict ourselves to item non-response. Item non-response may arise because a person refuses to answer to certain questions, e.g. if the question is too sensitive or is regarded as too...
Hansen, Dorte Gilså, Rosholm, Jens-Ulrik, Gichangi, Anthony, Vach, Werner
Background: the new antidepressants are generally effective and safe for older people, but may have serious side-effects. The use has been rapidly increasing, but focus on upper age groups has been...
Counting drugs to understand the disease: The case of measuring the diabetes epidemic (2007)
Støvring, Henrik, Andersen, Morten, Beck-Nielsen, Henning, Green, Anders, Vach, Werner
Abstract Background Diabetes prevalence increases globally with severe consequences for afflicted individuals and societies. Data on diabetes incidence and diabetes related mortality on a population...
Gatekeeper for coronary angiography: reply (2006)
Høilund-Carlsen, Poul F., Johansen, Allan, Vach, Werner, Haghfelt, Torben
Høilund-Carlsen, Poul F., Johansen, Allan, Christensen, Henrik Wulff, Vach, Werner, Møldrup, Mette, Bartram, Peter, ...
Aims To evaluate the impact of using myocardial perfusion scintigraphy (MPS) as gatekeeper for coronary angiography and revascularization in stable angina pectoris. Methods and results A prospective...
Gatekeeper for coronary angiography: reply (2006)
Høilund-Carlsen, Poul F., Johansen, Allan, Vach, Werner, Haghfelt, Torben
Tan, Qihua, Dahlgaard, Jesper, Vach, Werner, Abdallah, Basem M, Kassem, Moustapha, Kruse, Torben A
Abstract We introduce a non-parametric approach using bootstrap-assisted correspondence analysis to identify and validate genes that are differentially expressed in factorial microarray experiments....
Tan, Qihua, Christiansen, Lene, Bathum, Lise, Zhao, Jing H., Vach, Werner, Vaupel, James W., ...
Haplotype based linkage disequilibrium (LD) mapping exhibits higher power than the single locus approach because it makes use of the LD information contained in the flanking markers. New statistical...
Høilund-Carlsen, Poul F., Johansen, Allan, Christensen, Henrik Wulff, Vach, Werner, Møldrup, Mette, Bartram, Peter, ...
Aims To evaluate the impact of using myocardial perfusion scintigraphy (MPS) as gatekeeper for coronary angiography and revascularization in stable angina pectoris. Methods and results A prospective...
Tan, Qihua, Zhao, Jing H., Iachine, Ivan A., Hjelmborg, Jacob, Vach, Werner, Vaupel, James W., ...
This report investigates the power issue in applying the non-parametric linkage analysis of affected sib-pairs (ASP) [Kruglyak and Lander, 1995: Am J Hum Genet 57:439-454] to localize genes that...
Assessing genetic association with human survival at multi-allelic loci (2004)
Tan, Qihua, De Benedictis, Giovanna, Yashin, Anatoli I., Bathum, Lise, Christiansen, Lene, Dahlgaard, Jesper, ...
Genetic variation plays an important role in natural selection and population evolution. However, it also presents geneticists interested in aging research with problems in data analysis because of...
Hansen, Dorte Gilså, Vach, Werner, Rosholm, Jens-Ulrik, Søndergaard, Jens, Gram, Lars F, Kragstrup, Jakob
Background. Most antidepressant treatment is initiated and continued in general practice but, despite current guidelines, treatment duration is often short among patients with depression....
Hansen, Dorte Gilså, Vach, Werner, Rosholm, Jens-Ulrik, Søndergaard, Jens, Gram, Lars F., Kragstrup, Jakob
Background. Most antidepressant treatment is initiated and continued in general practice but, despite current guidelines, treatment duration is often short among patients with depression....
Hansen, Dorte Gilså, Vach, Werner, Rosholm, Jens-Ulrik, Søndergaard, Jens, Gram, Lars F., Kragstrup, Jakob
Background. Most antidepressant treatment is initiated and continued in general practice but, despite current guidelines, treatment duration is often short among patients with depression....
Tan, Qihua, Bathum, Lise, Christiansen, Lene, De Benedictis, Giovanna, Dahlgaard, Jesper, Frizner, N, ...
In this paper, we apply logistic regression models to measure genetic association with human survival for highly polymorphic and pleiotropic genes. By modelling genotype frequency as a function of...
Guido Schwarzer, Werner Vach, Martin Schumacher
The application of artificial neural networks (ANNs) for prognostic and diagnostic classification in clinical medicine has become very popular. Some indications might be derived from a recent...
this paper we investigate the bias due to a violation of the MAR assumption in the special case of logistic regression which aims to estimate adjusted odds ratios. We restrict ourselves to the case...
this paper we investigate the bias due to a violation of the MAR assumption in the special case of logistic regression which aims to estimate adjusted odds ratios. We restrict ourselves to the case...
Neural networks and logistic regression - Part I (1996)
Martin Schumacher, Reinhard Roßner, Werner Vach
Feed-forward neural networks have recently been applied in situations where an analysis based on the logistic regression model would have been a standard statistical approach; direct comparisons of...
Neural Networks and Logistic Regression (1996)
Werner Vach, Reinhard Roßner, Martin Schumacher
this paper we investigated whether neural nets are worth to be considered as an alternative to logistic models in settings relevant for biomedical research. The first drawback of neural nets is that...
Werner Vach, Ulrike Grömping, Ulrike Gr Omping, Kirstin Schulz
this paper we consider two approaches to analyze longitudinal data measured at time points t = 1; : : : ; T . Both approaches investigate the relationship between a (time-dependent) covariate X t and...
VACH, WERNER, SCHUMACHER, MARTIN
A logistic regression analysis based on the complete cases neglects the information due to subjects with missing values in at least one but not in all covariates. Three different approaches allowing...
The effects of missing values for a confounding variable are investigated in the setting of case-control studies in which, for simplicity, the effect of one binary risk factor and one categoric...
Counting drugs to understand the disease: The case of measuring the diabetes epidemic
Støvring, Henrik, Andersen, Morten, Beck-Nielsen, Henning, Green, Anders, Vach, Werner
Diagnosis and treatment of musculoskeletal chest pain: design of a multi-purpose trial
Stochkendahl, Mette J, Christensen, Henrik W, Vach, Werner, Høilund-Carlsen, Poul Flemming, Haghfelt, Torben, Hartvigsen, Jan
A new approach to isotonic agglomerative hierarchical clustering
Ultrametric, Local optimality, Least squares approximation, Average linkage, Approximation from above, complete linkage,