Glycosylated hemoglobin A1c (HbA1c) has become one of key components in new American Diabetes Association (ADA) diagnostic criteria for pre-diabetes and diabetes, which is not included in the World Health Organization (WHO) 1999 criteria. Thus, we aimed to compare the two criteria in diagnosis of pre-diabetes and diabetes in patients with non-acute coronary syndrome (non-ACS) in Chinese.

Non-ACS patients who had undergone elective coronary angiography (CAG) in Peking Union Medical College Hospital without previously known diabetes were enrolled consecutively from October 2013 to April 2014. Fasting plasma glucose (FPG), 2-hour plasma glucose after a 75 g oral glucose load(2hPG) and HbA1c levels before CAG were measured. Both WHO and new ADA criteria were applied for pre-diabetes and diabetes screening.

One hundred and thirty-nine patients were included, aged (61.9±10.1) years and 88(63.3%) were men among them. According to WHO 1999 criteria, 34 patients (24.4%) were normal glucose regulation, 57 (41.0%) pre-diabetes (including one impaired fasting glucose and 56 impaired glucose tolerance), and 48 (34.5%) newly diagnosed diabetes mellitus. ADA criteria identified 12 more patients with pre-diabetes and eight more with diabetes than WHO criteria. Compared with those diagnosed by both criteria, the proportion of women was higher in diabetic patients diagnosed with HbA1c alone. They also had lower hemoglobin [(124.88±17.74) g/L vs (140.15±15.17) g/L, P=0.013] and higher fibrinogen levels [(3.47±0.41) g/L vs (3.02±0.68) g/L, P=0.024] than those diagnosed by both criteria.

Compared with WHO 1999, new ADA criteria with HbA1c assessment are able to identify more previously unknown pre-diabetes and diabetes patients. Measurement of HbA1c might be needed to carry out routinely for screening patients with glucose metabolism abnormalities before elective CAG.

Diabetes mellitus; Hemoglobin A, glycosylated; Coronary angiography