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Citation/Reference Laure Wynants, Sabine Van Huffel, Ben Van Calster, (2015),

Prediction models in multicenter studies: methodological aspects and current state of the art

Archives of Public Health, 73 (Suppl 1), O3.

Archived version Final publisher’s version / pdf

Published version http://www.archpublichealth.com/content/pdf/2049-3258-73-S1- O3.pdf

Journal homepage http://www.archpublichealth.com/

Author contact Laure.wynants@esat.kuleuven.be + 32 (0)16 327670

IR url in Lirias https://lirias.kuleuven.be/handle/123456789/xxxxxx

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ORAL PRESENTATION Open Access

Prediction models in multicenter studies:

methodological aspects and current state of the art

Laure Wynants

*

, Sabine Van Huffel, Ben Van Calster From Methods in Epidemiology Symposium Leuven, Belgium. 17 September 2015

Increasingly, multicenter datasets are being used to develop or evaluate clinical risk prediction models. Such models estimate an individual’s probability that a certain disease or condition is present (diagnostic model) or that an event will occur in the future (prognostic model). Although multicenter studies enhance the gen- eralizability of the model, the clustered nature of the data poses several methodological challenges. We will provide an up to date overview of good practices to overcome these challenges.

When determining the required sample size, the num- ber of events per candidate variable (EPV) is crucial to prevent overfitting when building a prediction model.

We extend the EPV guidelines to multicenter studies, acknowledging the clustered nature of the data. During data collection, measurements of variables may differ between centers due to various reasons, such as subjec- tivity of measurements, differences in equipment and differences in patient populations. We show how the residual intraclass correlation can be used to quantify the intercenter variability. When building a prediction model, the clustered nature of the data should be taken into account during the data analysis, e.g. by using mixed effect models and variables at the center level.

Only mixed effect regression can result in a model that is simultaneously calibrated (i.e. gives accurate predicted probabilities) at the center level and the population level. We give the example of the ADNEX model that was built to distinguish between several types of adnexal masses. In the end, the performance of models may dif- fer between centers. We present how to evaluate the predictive performance of models in clustered data and show extensions to existing techniques to evaluate

discrimination, calibration and clinical utility, among others by the use of meta-analytic techniques.

Published: 17 September 2015

doi:10.1186/2049-3258-73-S1-O3

Cite this article as: Wynants et al.: Prediction models in multicenter studies: methodological aspects and current state of the art.Archives of Public Health 2015 73(Suppl 1):O3.

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Submit your manuscript at www.biomedcentral.com/submit KU Leuven, Leuven, Belgium

Wynantset al. Archives of Public Health 2015, 73(Suppl 1):O3

http://www.archpublichealth.com/content/73/S1/O3 ARCHIVES OF PUBLIC HEALTH

© 2015 Wynants et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://

creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/

zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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