A shorter oral glucose tolerance test (OGTT) measure may identify more patients with diabetes while maintaining good agreement with standard 2-hour criteria. An analysis published in BMJ Open Diabetes Research & Care evaluated whether 1-hour plasma glucose (1-h PG) concentration during OGTT could be used to diagnose diabetes mellitus (DM) and pre-diabetes.

The analysis included 1,021 outpatients who completed a 5-point OGTT. Prevalence rates were assessed using three approaches: standard American Diabetes Association (ADA) or World Health Organization (WHO) criteria, replacing 2-hour plasma glucose (2-h PG) with 1-h PG, and adding 1-h PG to existing criteria.

Based on ADA criteria, diabetes and pre-diabetes prevalence rates were 34.1% and 24.4%, respectively. Replacing 2-h PG with 1-h PG increased diabetes prevalence to 42.4% and changed pre-diabetes prevalence to 21.8%. Adding 1-h PG to the ADA criteria increased diabetes prevalence to 44.4%. Under WHO criteria, diabetes prevalence increased from 30.4% to 40.5% when 1-h PG replaced 2-h PG and to 43.9% when it was added.

Despite these shifts, 1-h PG showed good consistency with 2-h PG for diabetes (κ=0.7; 95% CI, 70.1%-78.4%) and pre-diabetes (κ=0.7; 95% CI, 64.5%-75.0%). For diabetes, AUC was 93.7% (95% CI, 92.2%-95.1%) for 1-h PG and 96.1% (95% CI, 94.7%-97.3%) for 2-h PG. For pre-diabetes, AUC was 71.8% (95% CI, 67.9%-75.8%) for 1-h PG and 70.4% (95% CI, 65.9%-74.5%) for 2-h PG.

Use of OGTT 1-h PG increased estimated diabetes prevalence while showing good agreement with existing diagnostic frameworks. Prospective studies are needed to confirm its clinical utility.