Received: 1 November 2018
Accepted: 14 June 2019
First Online: 10 July 2019
Ethics approval and consent to participate
: This study was deemed exempt by the University of Utah Institutional Review Board (IRB #00079432). As a result of this IRB exemption, informed consent was therefore also not required from participants for this retrospective study.
: Not applicable.
: Conflict of interest statement: Dr. Petigara is an employee of Merck & Co., Inc., Kenilworth, NJ, USA. Funding for this research was provided by Merck & Co., Inc., Kenilworth, NJ, USA.The authors declare that they have no competing interests.