Article History
Received: 2 October 2018
Accepted: 2 December 2018
First Online: 13 December 2018
Ethics approval and consent to participate
: This was a retrospective analysis and patients were not consented. The research was approved by the University of Witwatersrand Ethics Committee (Clearance Certificate No. M160134).
: All authors have reviewed and approve submission of this work.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.