Funding for this research was provided by:
Received: 24 October 2017
Accepted: 17 January 2018
First Online: 26 February 2018
Ethics approval and consent to participate
: This study was conducted with the approval of the regional ethics committee at Leiden University Medical Center. The IMPROVED study was approved by the Medical Ethics Committees of all participating hospitals. Informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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