gms | German Medical Science

MAINZ//2011: 56. GMDS-Jahrestagung und 6. DGEpi-Jahrestagung

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie e. V.
Deutsche Gesellschaft für Epidemiologie e. V.

26. - 29.09.2011 in Mainz

Evidence-based assessment and application of prognostic markers: The long way from single studies to meta-analysis

Meeting Abstract

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  • Willi Sauerbrei - Institut für Medizinische Biometrie und Informatik, Universitätsklinikum Freiburg, Freiburg
  • Richard Riley - Department of Public Health, Birmingham, UK
  • Doug Altman - Centre for Statistics in Medicine, Oxford, UK

Mainz//2011. 56. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 6. Jahrestagung der Deutschen Gesellschaft für Epidemiologie (DGEpi). Mainz, 26.-29.09.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11gmds091

doi: 10.3205/11gmds091, urn:nbn:de:0183-11gmds0914

Published: September 20, 2011

© 2011 Sauerbrei et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Background: The identification and assessment of prognostic markers constitutes one of the major tasks in clinical research. Despite huge research effort, the prognostic value of most traditional factors under discussion is uncertain and the usefulness of many specific markers is still unproven. Results from different studies are often contradictory, and a general assessment of the usefulness of a specific marker is very difficult. The number of markers that have emerged as clinically useful is pitifully small. One reason is that systematic reviews of prognostic marker studies have received insufficient attention in the literature. A critical issue for a summary assessment is the availability of individual patient data (IPD).

Methods: For some markers we discuss issues of analysis and reporting of primary prognostic marker studies, the feasibility of obtaining individual patient data from multiple studies on prognosis, and the quality of some meta analyses, with and without IPD data.

Results/Discussion: We will show that most individual studies are much too small and many of them have severe deficiencies in design and analysis, questioning the result of them. IPD allows a re-analysis of these studies but cannot overcome severe weaknesses in their design. In addition, publication bias is an important concern. We will argue that design, conduct, analysis and reporting of individual studies has to be improved and that any useful quantitative summary of observational studies ideally requires IPD and a close collaboration between different study groups. However, IPD is a necessary requirement, but it is not sufficient to assess the prognostic value of a marker according to EBM criteria. Most of the arguments transfer to a summary assessment of observational studies in epidemiology.


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