1. Health Sciences Research Office, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
2. School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
3. Department of Surgery, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; NIHR Global Surgery Unit – Surgical Statistics Hub, South Africa.