Received: 5 February 2019
Accepted: 6 June 2019
First Online: 30 July 2019
Ethics approval and consent to participate
: Not applicable, use of publicly available data set.
: Not applicable.
: CC reports personal fees from pharmaceutical companies, outside the submitted work. SH is the CEO of Clinical Outcomes Solutions, which received consulting fees from multiple pharmaceutical companies outside the submitted work. The other authors declare they have no competing interests.