[1] Univ Witwatersrand, Fac Hlth Sci, Sch Physiol, Cardiovasc Pathophysiol & Genom Res Unit, Johannesburg, South Africa
[2] Milpk Hosp, Rheumatol, Johannesburg, South Africa
[3] Univ Witwatersrand, Fac Hlth Sci, Charlotte Maxeke Johannesburg Acad Hosp, Rheumatol, Johannesburg, South Africa