Saving time by replacing the standardised two-hour oral glucose tolerance test with a one-hour test: Validation of a new screening algorithm in patients with coronary artery disease from the ESC-EORP EUROASPIRE V registry

Abstract

Aims: An oral glucose tolerance test (OGTT) combining fasting (FPG) and 2-hour plasma glucose (2hPG) is the most sensitive method for detecting type 2 diabetes (T2DM). Since it is considered time-consuming, we aim at validating a previously proposed screening algorithm based on a 1-hour plasma glucose (1hPG) with a 12 mmol/L threshold.

Methods: Nine-hundred-eighteen patients with coronary artery disease (CAD) without known T2DM from the EUROASPIRE V cross-sectional survey underwent an OGTT. The reference for T2DM was 2hPG ≥ 11.1 mmol/L. T2DM diagnosis by HbA1c ≥ 6.5%(48 mmol/mol), FPG ≥ 7.0 mmol/L, and 1hPG ≥ 12 mmol/L were compared with the outcome of 2hPG.

Results: Mean FPG, HbA1c and 2hPG were 6.1 mmol/L, 5.6%(38 mmol/mol) and 7.8 mmol/L respectively. Ninety-six patients (10%) were diagnosed with T2DM according to 2hPG. Using this definition, in the group with FPG < 6.5 mmol/L and 1hPG < 12 only 5 (1%) were misdiagnosed as false negatives. All patients with a FPG > 8.0 mmol/L and 1hPG > 15.0 mmol/L were identified as having T2DM. According to the algorithm, in 79% of patients T2DM could be excluded by combining FPG < 6.5 mmol/L and 1hPG < 12 mmol/L.

Conclusions: T2DM Screening by means of an algorithm combining FPG and 1hPG limits the demand of a 2hOGTT in 79% of CAD patients without known T2DM. HbA1c did not add to the information derived from this algorithm.

Keywords: Coronary Artery Disease; Diagnosis; Ischemic Heart Disease; OGTT; Prevention; Screening; Survey.