Do the Glucose Values Obtained in Patients Who Cannot Be Diagnosed with the Oral Glucose Tolerance Test (OGTT) Determine the Risk of Developing Diabetes?

Objective: Diabetes mellitus (DM) is a global health problem with an increasing prevalence over the years. Recent studies suggest that the first-hour glucose level in the Oral Glucose Tolerance Test (OGTT) could serve as a practical parameter to identify at-risk populations. This study aims to determine the predictor of diabetes based on baseline OGTTs in non-diabetic patients and establish a cut-off value for the Turkish population.

Methods: This study is a single-center retrospective cross-sectional study. Patients over 18 years of age who underwent OGTT for any reason between 2009 and 2014 were evaluated. Data were examined through the electronic hospital system in 2018, and 5874 patients included in the study. Exclusion criteria were the presence of diabetes at the time of OGTT, missing data, and repeated OGTTs.

Results: Diabetes was diagnosed in 1587 (27%) patients. The first-hour plasma glucose level in OGTT was more predictive of future diabetes development than fasting plasma glucose and second-hour plasma glucose levels (Area Under the Curve [AUC]: 0.76). The cut-off value for the first-hour plasma glucose was determined to be 168.5 mg/dL.

Conclusion: A first-hour plasma glucose level of ≥168.5 mg/dL in OGTT is a significant predictor of future diabetes development. This study is crucial as it is the first to determine a cut-off value for the Turkish population.

Cite this article as: Dilbil M, Yardımser M, Balcı MK. Do the glucose values obtained in patients who cannot be diagnosed with the oral glucose tolerance test (OGTT) determine the risk of developing diabetes? Endocrinol Res Pract. 2025;29(3):171-175.