Hambourg, Allemagne – During the 59th annual congress of the European Association for the Study of Diabetes (EASD) [1], Pr Jaakko Tuomilehto (Finnish Institute for Health and Welfare, Helsinki, Finland) made a plea for the 1-hour oral glucose tolerance test (1h-HGPO) in the detection of prediabetes and the diagnosis of type 2 diabetes.
“Currently, we diagnose type 2 diabetes (T2D) too late,” said Pr Jaakko Tuomilehto [2], who published an argument to revise the recommendations, co-signed in The Lancet Diabetes & Endocrinology [3] with six international experts.
Useful, clinically more acceptable, simpler to implement, and more cost-effective, the literature data are also sufficiently consistent for the level of glucose one hour after an oral glucose tolerance test (75g; 1h-HGPO) to become the new biomarker for detecting dysglycemia earlier than currently.
Currently, we diagnose type 2 diabetes
“The inability of current diagnostic criteria to detect dysglycemia earlier in the long trajectory leading to type 2 diabetes stems from four factors,” he explained, including the fact that dysglycemia is a continuous process.”
The second point is that between the American Diabetes Association (ADA) and the SGD, although the diagnostic criteria for glucose intolerance are identical, those that define impaired fasting glucose differ.
In addition, only the ADA recommends measuring HbA1c concentrations to detect prediabetes.
Moreover, plasma glucose and HbA1c concentrations are generally discordant in detecting dysglycemia. HbA1c concentrations can be influenced by anemia, chronic kidney disease, etc.
“In the bloodstream,” explains Prof Tuomilehto, “glucose behaves as follows: it increases in everyone, but in individuals with normal blood sugar levels, the increase is reasonable and returns to fasting levels within two hours. But within one hour, it is possible to identify either glucose intolerance or diabetes. You don’t need to wait two hours.”
Within one hour, it is possible to identify either glucose intolerance or diabetes. No need to wait two hours.
To support his opinion, the specialist highlights several studies and meta-analyses. A Brazilian longitudinal study (ELSA-Brazil; 15,105 participants followed for an average of 3.7 years) [4] evaluated the prognostic properties of five definitions of prediabetes based on their ability to predict who will progress to diabetes. It shows that impaired fasting glucose based on the criteria of the WHO and glucose intolerance better predict diabetes than the other three definitions of prediabetes, but their sensitivity is low. Impaired fasting glucose based on the ADA criteria has the highest sensitivity but classifies nearly half of adults as having prediabetes and poorly predicts diabetes. Only the combination of glycemic results and clinical features improves prognostic properties in at-risk individuals.
It is important to detect a high level on the 1-hour HGPO test before the development of glucose intolerance.
The authors of a meta-analysis [5] studied the implication of determining 1-hour oral glucose tolerance (1h-HGPO) in predicting T2D and cardiovascular diseases.
They concluded that several longitudinal studies have consistently shown that a 1h-HGPO ≥155 mg/dL could identify individuals at increased risk of diabetes among subjects with glucose intolerance.
In addition, they described the pathophysiological abnormalities associated with a 1h-HGPO ≥155 mg/dL, such as impaired insulin sensitivity, β cell dysfunction, and increased intestinal glucose absorption, all involved in the pathogenesis of T2D.
According to these authors, “although determining 1h-HGPO is not recommended by the ADA to identify high-risk individuals, the available evidence indicates that a value of 1h-HGPO ≥155 mg/dL can be a useful tool to identify, among subjects with glucose intolerance, those at increased risk of T2D and cardiovascular diseases.”
A 1h-HGPO ≥155 mg/dL can be useful to identify, among subjects with glucose intolerance, those at increased risk of T2D and cardiovascular diseases.
1h-HGPO, the evidence is accumulating
“We analyzed data from the Finnish study Finnish Diabetes Prevention Study and observed a reduction in the area under the curve for the 1-hour test compared to the 2-hour test,” emphasized Prof Tuomilehto. According to the studies and this analysis, a 1-hour HGPO >11.6 mmol/L (209 mg/dL) or 12.0 mmol/L seems to be the optimal threshold for diagnosing T2D.”
A value of 1h-HGPO ≥11.6 mmol/L has good sensitivity and specificity for the detection of type 2 diabetes, confirmed a meta-analysis published in 2021 [6].
A 2018 publication supports this position [7], as does the American primary care intervention study Stop Diabetes [8].
“Currently, we are working on a meta-analysis of observational studies to prospectively examine the incidence of diabetes,” announced Prof Jaakko Tuomilehto. “We performed the analysis with fasting blood glucose, 1-hour blood glucose (1h-HGPO), and 2-hour blood glucose (2h-HGPO). At this stage, the best predictive parameter for diabetes was blood glucose one hour after the oral glucose tolerance test.”
Prof Jaakko Tuomilehto declares the following conflicts of interest: Orion Pharma; Digostics ltd; Aktivolabs ltd
Follow Medscape en français on Twitter
