Читать книгу Clinical Dilemmas in Diabetes - Группа авторов - Страница 15

Individuals with prediabetes have abnormal glucose regulation and increased risk for developing DM type 2 (DM2) and its complications [6]. The diagnostic thresholds for DM are based on [1] the bimodal distribution of FPG and 2‐h PG during an OGTT and [2] the glycemic thresholds for the development of microvascular complications, specifically retinopathy (Figure 1.1). The bimodal distribution and glycemic thresholds for the development of microvascular complications have been demonstrated in many populations including the Pima, Nauruans, South Africans, Americans, Chinese, and Egyptians [7–15]. The bimodal distribution of glucose has been used to separate individuals into two groups: those with normoglycemia and those with hyperglycemia. IFG and IGT were defined as intermediates between normoglycemia and hyperglycemia. The diagnostic thresholds for FPG, 2‐h PG during a 75‐g OGTT, and HbA1c are relatively concordant in discriminating between the two components of a bimodal frequency distribution and their associations with microvascular complications [4]. It is important to note that defining a lower limit of an intermediate category of FPG, 2‐h PG during a 75‐g OGTT, and HbA1c is somewhat arbitrary because the risk of developing DM is a continuum that extends into the normoglycemic range [6].

FIG 1.1 Histogram with superimposed composite and component curves to describe the distribution of two‐hour plasma glucose levels following an oral glucose load. Glucose concentrations and frequencies were arbitrarily chosen to illustrate a bimodal distribution. The bimodal glucose distribution can be used to separate individuals into two groups, those with normoglycemia and those with hyperglycemia. Intermediate glucose concentrations between normoglycemia and hyperglycemia helped define the diagnostic thresholds for prediabetes.