The diagnostic accuracy of HbA 1c , compared to the oral glucose tolerance test, for screening for type 2 diabetes mellitus in Africa-A systematic review and meta-analysis

• Published in: Diabetic medicine 2022-04, Vol.39 (4), p.e14754
• Main Authors: Chivese, Tawanda, Hirst, Jennifer, Matizanadzo, Joshua T, Custodio, Michael, Farmer, Andrew, Norris, Shane, Levitt, Naomi
• Format: Article
• Language: English
• Subjects: Africa - epidemiology; Blood Glucose; Diabetes Mellitus; Diabetes Mellitus, Type 2 - diagnosis; Diabetes Mellitus, Type 2 - epidemiology; Fasting; Glucose Tolerance Test; Glycated Hemoglobin A - analysis; Humans
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.14754

To assess the diagnostic accuracy of glycated haemoglobin A (HbA ), compared to fasting plasma glucose (FPG) and the oral glucose tolerance test (OGTT), in screening for type 2 diabetes (T2D) in Africa. We systematically searched databases for studies that compared the HbA to either the OGTT, or the FPG for T2D diagnosis were included. The QUADAS 2 tool was used for assessing the quality of included studies. We used the split component synthesis (SCS) method for the meta-analysis of diagnostic accuracy studies to pool the studies for meta-analysis of sensitivity and specificity, primarily at the HbA ≥48 mmol/mol (6.5%) cut-off and at other cut-offs. We assessed heterogeneity using the I  statistic and publication bias using Doi plots. Eleven studies, from seven African countries, with 12,925 participants, were included. Against the OGTT, HbA ≥48 mmol/mol (6.5%) had a pooled sensitivity of 57.7% (95% confidence interval [CI] 43.4-70.9) and specificity of 92.3% (95% CI 83.9-96.5). Against the FPG, HbA ≥48 mmol/mol (6.5%) had a pooled sensitivity of 64.5% (95% CI 50.5-76.4) and specificity of 94.3% (95% CI 87.9-97.5). The highest sensitivity for HbA , against the OGTT, was at the 42 mmol/mol (6.0%) cut-off. In Africa, the HbA ≥48 mmol/mol (6.5%) cut-off may miss almost half of the individuals with T2D based on blood glucose measures.