What is Hyperglycaemia

Type 2 diabetes

• Type 2 diabetes¹ is diagnosed in case of
  • A 2hPG level of ≥11.1mmol/L (≥200mg/dL).
  • A FPG level of ≥7.0mmol/L (≥126mg/dL).
• Post-meal blood glucose levels are recorded 2 hours after an OGTT with intake of 75g glucose.⁴

• IGT entails a high risk of progressing to type 2 diabetes which is why it is increasingly referred to as ‘prediabetes’ by, among others, the American Diabetes Association.⁵
• The loss of early insulin secretion in IGT and type 2 diabetes is the result of malfunctioning of the pancreatic ß-cells. In the long-term, high blood glucose levels are toxic to ß-cells resulting in further deterioration of ß-cell function and worsening blood glucose control.⁶
• About 40-50% of people with IGT will develop type 2 diabetes (accompanied by an increased risk of cardiovascular disease and microvascular complications) within ten years.⁷
• The International Diabetes Federation (IDF) released a three-step strategy for type 2 diabetes prevention, including basic diagnosis and treatment recommendations:⁸
  
  • Step 1 is to identify individuals at high risk of developing type 2 diabetes through opportunistic screening in the clinic.
  • Step 2 is to measure a high-risk individual’s level of risk, measuring fasting blood glucose which should be followed by an OGTT to confirm the presence of prediabetes or diabetes.
  • Step 3 is intervention to lower an individual’s level of risk, in the first instance by lifestyle intervention (healthy diet, more exercise and weight loss).
  • However, the IDF recommends that ‘some patients, who cannot change their lifestyle sufficiently, will also require pharmacotherapy.’

Hyperglycemia related cardiovascular risks

• Prediabetes is often associated with a cluster of inter-related cardiovascular risk factors referred to as the metabolic syndrome, including hypertension, high LDL-cholesterol and low HDL-cholesterol.⁷
• But prediabetes is also a significant individual cardiovascular risk factor itself.⁷
• Consequently, the guidelines from the American Association of Clinical Endocrinologists (AACE) underline the results from epidemiologic studies which show that hyperglycemia is strongly associated with the subsequent development of cardiovascular disease and that patients with impaired glucose tolerance frequently have increased cardiovascular risk factors.⁹
• Various studies have shown: data on post-meal glycaemia provide better information about the future risk of cardiovascular disease (CVD) than data on fasting glycaemia, and post-meal hyperglycaemia also predicts increased cardiovascular risk in individuals with normal fasting glycaemia.¹⁰
• The DECODE¹¹ (Diabetes Epidemiology: Collaborative analysis Of Diagnostic criteria in Europe) study, involving 25,000 participants, showed that raised blood glucose to a specific level two hours after intake of 75g glucose (OGTT) is an independent risk factor for premature death. The study also found that:
  • People with type 2 diabetes were more than twice as likely to die during the follow-up period than people with normal blood glucose control.
  • People with IGT were 50% more likely to die of cardiovascular complications during follow-up than people with normal blood glucose control.
  • However, as there were four times as many people with IGT than with diabetes, there were more premature deaths attributable to IGT than to diabetes.
• Evidence from the Euro Heart Survey¹² and the China Heart Survey¹³ show that both prediabetes and type 2 diabetes are common and often undiagnosed in individuals with established CVD.
• As a result, the recent guideline of the European Society of Cardiology/European Association for the Study of Diabetes (ESC/EASD) on hyperglycaemia and CVD recommends early intervention of these at-risk patients to prevent disease progression.¹⁴