Perspective

Understanding the Cardiovascular Consequences of Diabetes

November 12, 2021| By Dr. Sandra Mitic | Critical Illness | English

The International Diabetes Federation (IDF) estimates that worldwide around 463 million people (aged 20‑79 years) have diabetes, which comprises around 9.3% of the world’s population.1 A little over 90% have type 2 diabetes.2 Experts predict that the number of diabetics will rise to 700 million within the next two decades.3 As a result, diabetes is likely to remain one of the greatest medical challenges in societies in upcoming years.

Special attention needs to be paid to the cardiovascular consequences of diabetes. Diabetes, and even persistent elevation of blood sugar levels as in prediabetes, are both associated with all types of cardiovascular diseases, the most significant cause of morbidity and mortality in the affected population groups.4 Elevated levels of blood glucose increase the risk of cardiovascular diseases through endothelial dysfunction, inflammation and the toxic effects of glucose on blood vessels.5

In type 2 diabetes, insulin resistance depletes a person’s tolerance to insulin, making the hormone less effective. More insulin is needed to initiate the glucose take up into fat and muscle cells and the liver. As a consequence, elevated blood glucose levels lead to local damage, predominantly in small blood vessels, causing inflammation and inadequate vasodilatation.6 Besides, elevated blood glucose levels are frequently associated with other metabolic risk factors for vessel damage, such as hypertension, dyslipidaemia and obesity. Other risks are smoking and low levels of physical activity.

Image 1

Type 1 diabetes is caused by the lack of insulin production due to autoimmune mediated ß‑cell destruction of the pancreas. The lack of insulin production results in the inability to use glucose for energy or to control blood sugar levels, resulting in hyperglyceamia with the described toxic effects on the blood vessels.

Image 2

Current medical evidence indicates that for people with diabetes the relative risk of cardiovascular diseases is higher by the factor 1.6 ‑ 2.6 compared to people without diabetes.7 This association has led to the prevalence of cardiovascular diseases in 32% of diabetic people in high- to middle-income countries worldwide.8 The most common are coronary heart disease and cerebrovascular disease. Cardiovascular diseases cause a significant reduction in the life expectancy of diabetics. Global numbers show that men with diabetes and aged 50 years, live an average 5.8 years shorter than the reference group of non-diabetics. For women, the difference is even greater – 6.4 years less on average. (See table below). If a distinction is made between type 1 and type 2 diabetes, life expectancy is even lower in the group of type 2 diabetes. Type 2 diabetes reduces life expectancy by at least 10 years compared to the non-diabetic population, with cardiovascular diseases as the main death cause.9

Image 3

But cardiovascular diseases do not only occur more frequently, they also occur 10‑15 years earlier in people with diabetes compared to those without. Diabetes accelerates the time to the first cardiovascular event and to organ damage, such as myocardial infarction or the first hospitalization for heart failure.10 People who have diabetes and at least one additional cardiovascular risk factor especially need to be considered to be at very high risk. Those affected have a distinct need for cardioprotection through comprehensive measures.

For type 2, the two major domains for the prevention of atherosclerotic risk are lifestyle management and management of cardiovascular risk factors. Lifestyle management includes positive effects through physical exercise, nutrition, weight management and smoking cessation. Cardiovascular risk factor management implies medical interventions, including: platelet aggregation inhibitors, management of blood pressure, optimization of cholesterol blood levels and glycaemic control.11

For type 1 diabetes, glycaemic control remains the most important focus in treatment.

Although control of hyperglycaemia shows benefits in reduction of cardiovascular events, both the increased risk of hypoglycaemia and the high demands on compliance mean this therapeutic approach is not applicable to all patients. Other types of treatments are urgently needed for the always growing number of people who have diabetes and the cardiovascular diseases resulting from diabetes.

Trials for new anti-diabetes treatments have already shown benefits of cardiovascular protection. Some of the new classes of agents include the glucagon-like peptide 1 receptor agonists (GLP‑1 RAs) and the sodium glucose cotransporter‑2 (SGLT‑2) inhibitors for type 2 diabetes. Further new methods have emerged, such as RNA therapeutics, agents targeting distinct components of the immune/inflammatory response and molecules that block the actions of receptor for advanced glycation endproducts (RAGE).12 These may hold potential as new therapies for the cardiovascular consequences of both type 1 and type 2 diabetes.

The insurance industry must be prepared for increasing numbers of diabetics within the existing portfolio and among new applicants – along with the associated cardiovascular and other health risks, such as kidney disease, neuropathy or eye diseases. Hopefully, on the other hand, some of the new treatment methods under development will have a positive influence on the course of diabetes and its concomitant diseases in the future.

Did you already know that diabetes is also intimately associated with mental health problems? Read more about it in our next blog The Impact of Diabetes on Mental Health by Dr. Chris Ball.

Endnotes
  1. International Diabetes Federation, IDF Diabetes Atlas, 9th edition 2019.
  2. Newman JD et al.; Primary Prevention of Cardiovascular Disease in Diabetes Mellitus; J Am Coll Cardiol 2017;70:883.
  3. Ibid, see endnote 1.
  4. Ibid, see endnote 2.
  5. Ibid, see endnote 1.
  6. Einarson et al.; Prevalence of cardiovascular disease in type 2 diabetes: a systematic literature review of scientifc evidence from across the world in 2007–2017; Cardiovasc Diabetol (2018) 17:83.
  7. Ibid, see endnote 1.
  8. Ibid.
  9. Ibid, see endnote 6.
  10. Mc Murray JJV et al.; Heart failure: a cardiovascular outcome in diabetes that can no longer be ignored; Lancet Diabetes Endocrinol 2014; 2:843‑51.
  11. Ibid, see endnote 2.
  12. Schmidt A.; Diabetes and Cardiovascular Disease: Emerging Therpeutic Approaches. Arterioscler Thromb Vasc Biol. 2019 April; 39(4):558‑568.

 

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