Causal Model Building in the Context of Cardiac Rehabilitation: A Systematic Review

Nilufar Akbari; Georg Heinze; Geraldine Rauch; Ben Sander; Heiko Becher; Daniela Dunkler

doi:10.3390/ijerph20043182

Causal Model Building in the Context of Cardiac Rehabilitation: A Systematic Review

Int J Environ Res Public Health. 2023 Feb 11;20(4):3182. doi: 10.3390/ijerph20043182.

Authors

Nilufar Akbari¹, Georg Heinze², Geraldine Rauch^{1

3}, Ben Sander¹, Heiko Becher⁴, Daniela Dunkler²

Affiliations

¹ Institute of Biometry and Clinical Epidemiology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany.
² Center for Medical Data Science, Institute of Clinical Biometrics, Medical University of Vienna, Spitalgasse 23, 1090 Vienna, Austria.
³ Technische Universität Berlin, Straße des 17, Juni 135, 10623 Berlin, Germany.
⁴ Institute of Global Health, University Hospital Heidelberg, Im Neuenheimer Feld 130.3, 69120 Heidelberg, Germany.

Abstract

Randomization is an effective design option to prevent bias from confounding in the evaluation of the causal effect of interventions on outcomes. However, in some cases, randomization is not possible, making subsequent adjustment for confounders essential to obtain valid results. Several methods exist to adjust for confounding, with multivariable modeling being among the most widely used. The main challenge is to determine which variables should be included in the causal model and to specify appropriate functional relations for continuous variables in the model. While the statistical literature gives a variety of recommendations on how to build multivariable regression models in practice, this guidance is often unknown to applied researchers. We set out to investigate the current practice of explanatory regression modeling to control confounding in the field of cardiac rehabilitation, for which mainly non-randomized observational studies are available. In particular, we conducted a systematic methods review to identify and compare statistical methodology with respect to statistical model building in the context of the existing recent systematic review CROS-II, which evaluated the prognostic effect of cardiac rehabilitation. CROS-II identified 28 observational studies, which were published between 2004 and 2018. Our methods review revealed that 24 (86%) of the included studies used methods to adjust for confounding. Of these, 11 (46%) mentioned how the variables were selected and two studies (8%) considered functional forms for continuous variables. The use of background knowledge for variable selection was barely reported and data-driven variable selection methods were applied frequently. We conclude that in the majority of studies, the methods used to develop models to investigate the effect of cardiac rehabilitation on outcomes do not meet common criteria for appropriate statistical model building and that reporting often lacks precision.

Keywords: cardiac rehabilitation; causal regression modeling; functional forms; variable selection.

Publication types

Systematic Review
Review
Research Support, Non-U.S. Gov't

MeSH terms

Cardiac Rehabilitation*
Humans
Models, Statistical
Models, Theoretical

Grants and funding

This work was supported through the joint German-Austrian DFG and FWF project [DFG: RA-2347/8-1] to Geraldine Rauch, [DFG: BE-2056/22-1] to Heiko Becher and [FWF: I-4739-B] to Daniela Dunkler. Apart from this project, this research received no additional funding.