Cardiometabolic risk profile of participants with prediabetes diagnosed by HbA1c criteria in an urban Hong Kong Chinese population over 40 years of age.

AIMS: To investigate the usefulness of the additional measurement of HbA1c , compared with performing only the oral glucose tolerance test (OGTT), in identifying participants at increased cardiometabolic risk, in an urban Chinese population.
METHODS: All participants from the fourth visit of the population-based Hong Kong Cardiovascular Risk Factors Prevalence Study, without known diabetes, were included. All had their glycaemic status assessed by OGTT and HbA1c , according to American Diabetic Association 2010 criteria.
RESULTS: Based on OGTT criteria alone, 3.5% of the study cohort (N = 1300) had diabetes and 19.2% had prediabetes. Based on HbA1c criteria only, 6.2% had diabetes and 61.2% had prediabetes. The measurement of HbA1c , in addition to the OGTT, increased the proportion of participants with diabetes to 7.8% and with prediabetes to 65.3%. Subjects with prediabetes having raised HbA1c but normal glycaemia (N = 600) had waist circumference, systolic blood pressure, fasting glucose, insulin resistance index (HOMA-IR), Gutt Index and Framingham 10-year cardiovascular risk scores intermediate between those with both normal HbA1c and glycaemia (N = 350), and those with impaired fasting glucose and/or impaired glucose tolerance (N = 249; all P < 0.01).
CONCLUSION: The measurement of HbA1c in our population, in addition to the OGTT, results in the detection of a large number of participants with prediabetes having raised HbA1c but normal glycaemia who have a cardiometabolic risk profile intermediate between impaired fasting glucose and/or impaired glucose tolerance and normal participants, and would benefit from early lifestyle intervention.