The glucose triad and its role in comprehensive glycaemic control: current status, future management

Abstract

The prevalence of type 2 diabetes across the world has been described as a global pandemic. Despite significant efforts to limit both the increase in the number of cases and the long-term impact on morbidity and mortality, the total number of people with diabetes is projected to continue to rise and most patients still fail to achieve adequate glycaemic control. Optimal management of type 2 diabetes requires an understanding of the relationships between glycosylated haemoglobin (HbA(1c)), fasting plasma glucose and postprandial glucose (the glucose triad), and how these change during development and progression of the disease. Early and sustained control of glycaemia remains important in the management of type 2 diabetes. The contribution of postprandial glucose levels to overall glycaemic control and the role of postprandial glucose targets in disease management are currently debated. However, many patients do not reach HbA(1C) targets set according to published guidelines. As recent data suggest, if driving HbA(1C) down to lower target levels is not the answer, what other factors involved in glucose homeostasis can or should be targeted? Has the time come to change the treatment paradigm to include awareness of the components of the glucose triad, the existence of glucose variability and their potential influence on the choice of pharmacological treatment? It is becomingly increasingly clear that physicians are likely to have to consider plasma glucose levels both after the overnight fast and after meals as well as the variability of glucose levels, in order to achieve optimal glycaemic control for each patient. When antidiabetic therapy is initiated, physicians may need to consider selection of agents that target both fasting and postprandial hyperglycaemia.

Figure 1

HbA_1C, postprandial glucose and fasting plasma glucose interrelate and are essential targets for intervention in attempts to optimise overall glycaemic control. This figure was published in Diabetes and Metabolism; 32: Special Issue no 2. Monnier L, Colette C, Boniface H, Contribution of postprandial glucose to chronic hyperglycaemia: from the “glucose triad” to the trilogy of “sevens”. 2S11–2S16, Copyright Elsevier 2006

Figure 2

Blood glucose profile over 24 h in an individual with type 2 diabetes

Figure 3

The role of GLP-1 and GIP in glucose homeostasis. Key defects in individuals with type 2 diabetes are shown in red circles

Figure 4

The 24-h recordings from a continuous glucose monitoring system in five groups of patients with type 2 diabetes. Blue: HbA_1C < 6.5%; red: ≥ 6.5% to < 7%; green: ≥ 7% to < 8%; orange: ≥ 8% to < 9%; purple: ≥ 9%. Reproduced with permission from Monnier L et al. Diabetes Care 2007;30:263–9

Figure 5

Individual 24-h recordings from a continuous glucose monitoring system in four patients with type 2 diabetes on insulin therapy and a mean HbA_1C of 6.7%