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

RESEARCH ARTICLE 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 Thomas R. Hird1,2, Fraser J. Pirie3, Tonya M. Esterhuizen4, Brian O’Leary5, Mark I. McCarthy6, Elizabeth H. Young1,2, Manjinder S. Sandhu1,2*, Ayesha A. Motala3* a11111 1 Department of Medicine, University of Cambridge, Cambridge, United Kingdom, 2 Wellcome Trust Sanger Institute, Hinxton, United Kingdom, 3 Department of Diabetes and Endocrinology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa, 4 Centre for Evidence-Based Health Care, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa, 5 Research and Policy Department, Office of Strategy Management, eThekwini Municipality, Durban, South Africa, 6 Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, United Kingdom * (MSS); (AAM) OPEN ACCESS Citation: Hird TR, Pirie FJ, Esterhuizen TM, O’Leary B, McCarthy MI, Young EH, et al. (2016) 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. PLoS ONE 11(8): e0161966. doi:10.1371/journal. pone.0161966 Editor: Harald Staiger, Medical Clinic, University Hospital Tuebingen, GERMANY Received: May 16, 2016 Accepted: August 15, 2016 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. Published: August 25, 2016 Copyright: © 2016 Hird et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: We aim to facilitate data access for all bona fide researchers. Requests for access to the data from the Durban Diabetes Study will be granted for all research consistent with the consent provided by participants. This would include any research in the context of health and disease, that does not involve identifying the participants in any way. The African Partnership for Chronic Disease (APCDR) committees are responsible for curation, storage, and sharing of the data under managed access. Requests for access to Research Design and 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 PLOS ONE | DOI:10.1371/journal.pone.0161966 August 25, 2016 1 / 12 Diabetes and HbA1c in Black South Africans data may be directed to . Applications are reviewed by an independent data access committee (DAC) and access is granted if the request is consistent with the consent provided by participants. The data producers may be consulted by the DAC to evaluate potential ethical conflicts. Requestors also sign an agreement which governs the terms on which access to data is granted. Funding: The study was partly supported by the Wellcome Trust (grant number 098051), the African Partnership for Chronic Disease Research (Medical Research Council UK partnership grant number MR/ K013491/1), the National Institute for Health Research, Cambridge Biomedical Research Centre (UK). The study was also partly supported by the following commercial funders; Novo-Nordisk (South Africa), Sanofi Aventis (South Africa), and MSD Pharmaceuticals (Pty) Ltd (Southern Africa). These funders played no role in the study design, conduct or analysis, or in the decision to submit the manuscript for publication. Competing Interests: These funders played no role in the study design, conduct or analysis, or in the decision to submit the manuscript for publication and do not alter our adherence to PLOS ONE policies on sharing data and materials. 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. Introduction Sub-Saharan Africa (SSA) is experiencing a dramatic increase in diabetes. A consequence of rapid demographic and epidemiological transitions, the number of people with diabetes is projected to more than double to 34.2 million by 2040 [1, 2]. An estimated 66.7% of people living with diabetes in SSA are undiagnosed and therefore more at risk of developing harmful and costly complications, the highest proportion of any region in the world [1]. This poses a huge challenge in many SSA countries where over-burdened and under-resourced health systems already have a shortfall of diabetes services [3, 4]. Consistent and comparable measures of glycaemia are important for accurate screening and diagnosis of diabetes and for population-level surveillance, including inter- and intra-population prevalence comparisons, and subsequent targeting of services and resources to high-risk populations. Glycated haemoglobin (HbA1c) is recommended as an additional tool to glucosebased measures (fasting plasma glucose [FPG] and 2-hr plasma glucose (2PG) during an oral glucose tolerance test [OGTT]) for the diagnosis of diabetes [5–7]. However, HbA1c can provide different diabetes prevalence estimates and identifies a different population as having diabetes compared with FPG and OGTT. This degree of discordance varies between populations, by ethnicity, and according to the burden of clinical conditions affecting HbA1c, including anaemias, haemoglobinopathies and infection, potentially limiting the utility of HbA1c for the diagnosis and detection of diabetes [8–10]. However, this has not been esta (...truncated)