Fasting glucose, HbA1c, or oral glucose tolerance testing for the detection of glucose abnormalities in patients with acute coronary syndromes.

BACKGROUND

Due to the negative prognostic impact, it is important to accurately detect undiagnosed glucose perturbations in patients with acute coronary syndromes (ACS).

DESIGN

This study compares oral glucose tolerance test (OGTT) to fasting plasma glucose (FPG) and HbA1c as screening tools.

METHODS

Patients hospitalized for ACS had an OGTT, FPG, and HbA1c measured 4-21 (median 6) days after admission as a screening process for an intervention study.

RESULTS

Out of 174 patients, 75 (43%) had a normal glucose tolerance, 63 (36%) impaired glucose tolerance (IGT), and 36 (21%) diabetes type 2 (T2DM). Of these, 20 were non-eligible, and of the remaining 79 patients, 52 had IGT and 27 T2DM according to the OGTT. In patients with IGT, the median FPG was 6.0 mmol/l and the median HbA1c was 39 mmol/mol. The corresponding levels in patients with T2DM were 6.3 mmol/l and 41 mmol/mol, respectively. Seventeen of the 27 patients with T2DM according to OGTT had not been disclosed if the screening had been based on FPG. HbA1c identified two patients.

CONCLUSIONS

Compared to OGTT, the use of FPG or HbA1c alone leaves a majority of patients with IGT or T2DM undetected when screening for unknown glucose perturbations as a part of total risk assessment of patients with ACS.