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1-hour, 2-hour OGTT similarly predict prediabetes in adolescent girls
In adolescent girls with obesity, a 1-hour oral glucose tolerance test demonstrated diagnostic accuracy similar to that of a 2-hour OGTT for predicting prediabetes, according to findings published in Pediatric Diabetes.
“In up to 25% of youth who develop [type 2 diabetes], the fasting, 2-hour glucose concentration of HbA1c may be below the prediabetes diagnostic thresholds 2 years prior to diabetes diagnosis,” Kannan Kasturi, MD, a pediatric endocrinologist with Essentia Health-Duluth Clinic in Duluth, Minnesota, and colleagues wrote in the study background. “The need to improve risk stratification is further amplified in adolescent girls who have high rates of developing [type 2 diabetes] and may benefit from targeted, intensive intervention programs.”
Kasturi and colleagues analyzed data from adolescent girls with obesity but without diabetes who underwent a multiple-sample OGTT at baseline (n = 93), 6 weeks (n = 83) and 1 year (n = 72) as part of a randomized controlled trial of cognitive behavioral therapy vs. health education (mean age, 15 years). Researchers obtained plasma samples to measure glucose and insulin concentrations at 0, 30, 60, 90 and 120 minutes. Prediabetes was defined as a fasting glucose level between 100mg/dL and 126 mg/dL and/or a 2-hour glucose level between 140 mg/dL and 200 mg/dL. Researchers compared short-term reproducibility (baseline to 6 weeks) and predictive ability for prediabetes (baseline to 1 year) for each feature using standard fasting and 2-hour OGTT criteria.
The percentage of youths with prediabetes (12%) was the same at baseline and at 6 weeks, according to researchers. Six girls diagnosed with prediabetes at baseline were reclassified as having normal glucose tolerance at 6 weeks, whereas eight girls with normal glucose tolerance at baseline were reclassified as having prediabetes at 6 weeks. The researchers did not observe differences between area under the receiver operating characteristic curve (ROC-AUC) for morphological features of the OGTT when compared at baseline and 6 weeks, noting that there was fair to moderate short-term reproducibility.
Among 72 girls examined at 1-year follow-up, 11 had prediabetes at baseline and seven had prediabetes at 1 year, the researchers wrote. Compared with OGTT criteria, ROC-AUC was lower for monophasic curve variable (0.42; 95% CI, 0.22-0.63), but not different for 1-hour glucose (0.67; 95% CI, 0.48-0.88), glucose peak at 30 minutes (0.68; 95% CI, 0.49-0.87) or a combination of 1-hour glucose and glucose peak variables (0.77; 95% CI, 0.62-0.93).
“These findings are of potential clinical importance because they suggest that obtaining a 1-hour OGTT, with blood glucose sampling at 0, 30 and 60 minutes, has similar diagnostic accuracy to a 2-hour OGTT for predicting prediabetes and, thus, could be a shorter, clinically acceptable alternative for assessing the risk of progression to prediabetes,” the researchers wrote.
The researchers added that future studies are warranted to confirm whether using the morphological features obtained during a 1-hour OGTT may be cost-effective and efficacious among all youths at risk for prediabetes. – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.
Editor's note: This article was updated on December 17 to correct the definition of prediabetes.