Current diagnostic criteria identify risk for type 2 diabetes too late

The inadequacy of current diagnostic criteria to detect dysglycaemia earlier in the lengthy trajectory to type 2 diabetes could inadvertently be contributing to the burgeoning prevalence of prediabetes and diabetes. This inadequacy originates from several factors. First, criteria for prediabetes are confusing because of the different glucose threshold concentrations recommended by the American Diabetes Association (ADA) and WHO: although the recommended diagnostic criteria for impaired glucose tolerance are the same, those that define impaired fasting glucose are different. 1 Makaroff LE The need for international consensus on prediabetes. Lancet Diabetes Endocrinol. 2017; 5: 5-7 Summary Full Text Full Text PDF PubMed Scopus (30) Google Scholar Furthermore, ADA (but not WHO due to lack of evidence) recommends measuring HbA1c concentrations for detecting prediabetes. 1 Makaroff LE The need for international consensus on prediabetes. Lancet Diabetes Endocrinol. 2017; 5: 5-7 Summary Full Text Full Text PDF PubMed Scopus (30) Google Scholar An international consensus is therefore required to resolve these discrepancies. 1 Makaroff LE The need for international consensus on prediabetes. Lancet Diabetes Endocrinol. 2017; 5: 5-7 Summary Full Text Full Text PDF PubMed Scopus (30) Google Scholar Second, although glucose criteria are absolute, dysglycaemia is generally recognised to occur as a continuous process, and therefore any threshold values will be arbitrary. 2 ElSayed NA Aleppo G Aroda VR et al. 2. Classification and diagnosis of diabetes: standards of care in diabetes—2023. Diabetes Care. 2023; 46: S19-S40 Crossref PubMed Scopus (147) Google Scholar Third, plasma glucose and HbA1c concentrations are discordant for detecting dysglycaemia, with only a small proportion of the population showing overlapping results. Many clinical conditions can affect HbA1c concentrations (eg, anaemia, genetics, racial or ethnic differences, chronic kidney disease, and haemoglobinopathies), which can result in either overestimation or underestimation of diabetes prevalence. 3 Bergman M Manco M Sesti G et al. Petition to replace current OGTT criteria for diagnosing prediabetes with the 1-hour post-load plasma glucose ≥155 mg/dL (8·6 mmol/L). Diabetes Res Clin Pract. 2018; 146: 18-33 Summary Full Text Full Text PDF PubMed Scopus (59) Google Scholar Finally, physiological fasting and 2-h postprandial glucose concentrations are substantially lower than the currently established criteria for defining prediabetes and diabetes, thus leading to increased risk of progressing to type 2 diabetes. 4 Ferrannini E Manca ML Identifying glucose thresholds for incident diabetes by physiological analysis: a mathematical solution. Am J Physiol Regul Integr Comp Physiol. 2015; 308: R590-R596 Crossref PubMed Scopus (4) Google Scholar For example, fasting plasma glucose concentrations less than 5·6 mmol/L in young men (aged 26–45 years) predicted progression to type 2 diabetes nearly 6 years later. 5 Tirosh A Shai I Tekes-Manova D et al. Normal fasting plasma glucose levels and type 2 diabetes in young men. N Engl J Med. 2005; 353: 1454-1462 Crossref PubMed Scopus (406) Google Scholar