. 2018 Aug 1;39(37):3417–3438. doi: 10.1093/eurheartj/ehy407
© The Author(s) 2018. Published by Oxford University Press on behalf of the European Society of Cardiology.
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 reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 1.
Confounding in non-randomized studies.