1. University of Cape Town and Stellenbosch University; Division of Emergency Medicine; Faculty of Health Sciences, University of Cape Town Anzio Road Observatory Cape Town South Africa 7701
2. University of Cape Town; Department of Medicine; Cape Town South Africa
3. University of Birmingham; Institute of Applied Health Research; Edgbaston Birmingham UK B15 2TT
4. University of Cape Town; Division of Clinical Pharmacology, Department of Medicine; Cape Town South Africa
5. Stellenbosch University; Centre for Evidence-based Health Care, Faculty of Medicine and Health Sciences; PO Box 241 Cape Town South Africa 8000