1. Division of Rheumatology, Chris Hani Baragwanath Academic Hospital, Faculty of Health Sciences and University of the Witwatersrand, Johannesburg, South Africa
2. Department of Medicine, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
3. Division of Rheumatology, Department of Internal Medicine, Chris Hani Baragwanath Academic Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa