title: Burden of Diabetes and First Evidence for the Utility of HbA1c for Diagnosis and Detection of Diabetes in Urban Black South Africans: The Durban Diabetes Study.
abstract: OBJECTIVE
  Glycated haemoglobin (HbA1c) is recommended as an additional tool to glucose-based measures (fasting plasma glucose [FPG] and 2-hour plasma glucose [2PG] during oral glucose tolerance test [OGTT]) for the diagnosis of diabetes; however, its use in sub-Saharan African populations is not established. We assessed prevalence estimates and the diagnosis and detection of diabetes based on OGTT, FPG, and HbA1c in an urban black South African population.
  
  
  METHODS
  We conducted a population-based cross-sectional survey using multistage cluster sampling of adults aged ≥18 years in Durban (eThekwini municipality), KwaZulu-Natal. All participants had a 75-g OGTT and HbA1c measurements. Receiver operating characteristic (ROC) analysis was used to assess the overall diagnostic accuracy of HbA1c, using OGTT as the reference, and to determine optimal HbA1c cut-offs.
  
  
  RESULTS
  Among 1190 participants (851 women, 92.6% response rate), the age-standardised prevalence of diabetes was 12.9% based on OGTT, 11.9% based on FPG, and 13.1% based on HbA1c. In participants without a previous history of diabetes (n = 1077), using OGTT as the reference, an HbA1c ≥48 mmol/mol (6.5%) detected diabetes with 70.3% sensitivity (95%CI 52.7-87.8) and 98.7% specificity (95%CI 97.9-99.4) (AUC 0.94 [95%CI 0.89-1.00]). Additional analyses suggested the optimal HbA1c cut-off for detection of diabetes in this population was 42 mmol/mol (6.0%) (sensitivity 89.2% [95%CI 78.6-99.8], specificity 92.0% [95%CI: 90.3-93.7]).
  
  
  CONCLUSIONS
  In an urban black South African population, we found a high prevalence of diabetes and provide the first evidence for the utility of HbA1c for the diagnosis and detection of diabetes in black Africans in sub-Saharan Africa.
authors: Department of Medicine, University of Cambridge, Cambridge, United Kingdom.|Wellcome Trust Sanger Institute, Hinxton, United Kingdom.
authors: Thomas R
authors: TR
authors: Hird
authors: Department of Diabetes and Endocrinology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors: Fraser J
authors: FJ
authors: Pirie
authors: Centre for Evidence-Based Health Care, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa.
authors: Tonya M
authors: TM
authors: Esterhuizen
authors: Research and Policy Department, Office of Strategy Management, eThekwini Municipality, Durban, South Africa.
authors: Brian
authors: B
authors: O'Leary
authors: Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, United Kingdom.
authors: Mark I
authors: MI
authors: McCarthy
authors: Department of Medicine, University of Cambridge, Cambridge, United Kingdom.|Wellcome Trust Sanger Institute, Hinxton, United Kingdom.
authors: Elizabeth H
authors: EH
authors: Young
authors: Department of Medicine, University of Cambridge, Cambridge, United Kingdom.|Wellcome Trust Sanger Institute, Hinxton, United Kingdom.
authors: Manjinder S
authors: MS
authors: Sandhu
authors: Department of Diabetes and Endocrinology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
authors: Ayesha A
authors: AA
authors: Motala
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044383:Black People / Q000706:statistics & numerical data; D001786:Blood Glucose / Q000032:analysis; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D005215:Fasting / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012372:ROC Curve; D013019:South Africa / Q000453:epidemiology; D014504:Urban Health / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin