Coronary Heart Disease And Diabetes: Connection

Overview

Did you know that coronary heart disease (CHD) is a major cause of death worldwide? Nearly 200 million people are suffering with CHD. It is the most common type of heart disease, also often known as coronary artery disease or ischemic heart disease. It is caused by the accumulation of fatty substance (plaque) into the vessel wall which makes the blood vessel narrow, blocking the supply of blood and oxygen to the heart. Blockage of oxygen-rich blood could lead to heart attack and cardiac arrest. People having coronary heart disease need lifestyle changes, medication and surgery to manage conditions and prevent future health issues.

Diabetes is a hormonal disorder characterized by too high or too low blood glucose levels. It occurs when the pancreas does not produce enough insulin or develops resistance against insulin; insulin is a hormone that helps to take glucose from the blood to the cells and maintain a normal glucose level. Its primary symptoms are increased thirst, frequent urination and increased appetite. Over time, diabetes damages the body and has a negative effect on each organ. Diabetic patients need medications and lifestyle modification to prevent complications including cardiovascular issues, kidney damage, metabolic problems, GI issues and more.

Coronary heart disease and diabetes are interlinked with each other because diabetes has the potential to cause cardiovascular issues. Those who have diabetes for a longer period are at a higher risk of developing coronary heart disease.

What is coronary heart disease?

Causes of CHD

A number of factors have contributed to coronary heart disease, these are mainly classified into two groups:¹

1. Non-modifiable causes: Those that cannot be changed including age, genetic factors, family history and gender
2. Modifiable causes: These factors can be altered by lifestyle modification and proper treatment including smoking, excessive alcohol, obesity, cholesterol, hypertension and diabetes

Symptoms of CHD

Symptoms of coronary heart disease are as follows:

• Shortness of breath (dyspnea)
• Tightening of chest or chest pain
• Pain radiating in neck, arm, shoulder
• Unconsciousness/faintness
• Numbness due to blockage of blood flow
• Weakness

Complications related to CHD

Coronary heart disease can weaken the muscles of the heart and increase the risk of other heart diseases that are:²

• Heart failure
• Arrhythmia (irregular heartbeat)
• Ventricular heart disease
• Cardiac arrest

What is diabetes?

Types of diabetes

There are two main types of diabetes.

1. Type 1 Diabetes: It is an autoimmune disease in which the immune system attacks the pancreas and damages the cell that produces insulin; therefore, it is unable to produce enough insulin resulting in insulin resistance
2. Type 2 Diabetes: The pancreas produces insulin but cannot use it efficiently and develops insulin resistance

Causes of diabetes

The causes of diabetes are differentiated by what type of diabetes it is:

Causes of type 1 diabetes include autoimmune disease, genetic mutation and pancreatic damage whereas type 2 diabetes can be caused by insulin resistance, obesity, family history, physical inactivity, high blood pressure, medicines (steroids), Asian or African genes and diabetes during pregnancy (gestational diabetes).

Symptoms of diabetes

Symptoms of diabetes are as follows:

• Increased thirst and appetite
• Frequent urination
• Fatigue and weakness
• Numbness in hands and feet
• Weight loss
• Blurry vision
• Wounds cannot heal easily

Complications related to diabetes

High glucose levels over a longer period can increase the risk and severity of complications. Eventually,  it will affect each organ of the body. These complications are:

• Nerve damage
• Cardiac disease
• Kidney damage
• Liver damage
• Effect on eye vision
• Diabetes-related foot disease
• Prone to infections
• Hearing loss
• Oral health issues

The pathophysiological connection between coronary heart disease and diabetes

People with diabetes are at high risk for developing coronary heart disease because diabetes has negative effects on the heart. There are several mechanisms by which diabetes can cause coronary heart disease. These include:³

1. Insulin resistance: In diabetes, your body is resistant to insulin, leading to hyperglycemia (high glucose level). High levels of glucose can damage blood vessels, which promotes the accumulation of plaque in the vessel wall and increases the risk of coronary heart disease³
2. Inflammation: insulin resistance or hyperglycemia can trigger an inflammatory response in the body. Inflammation promotes the growth of plaque and blood clots in vessels. Eventually, it will lead to coronary heart disease⁴
3. Dyslipidemia: Dyslipidemia is the elevation of lipid levels (cholesterol, triglycerides, high or low-density lipoprotein) in the blood. High insulin levels disturb the levels of triglycerides or low-density lipoprotein and it is susceptible to plaque formation which contributes to coronary heart disease⁴
4. Epithelial dysfunction: Diabetes can damage the epithelial layer of arteries. Any damage to the epithelial layer will make arteries narrow. As a result, blood and oxygen cannot reach the heart and contribute to heart disease⁴
5. Obesity and hypertension: Obesity and hypertension (high blood pressure) both are common in diabetes. Obesity can increase the risk of insulin resistance whereas high blood pressure has the potential to damage blood vessels. Eventually, both factors will increase the risk of damage to the heart⁴

Epidemiological evidence

Statistics and prevalence of coronary heart disease in diabetic patients

The prevalence of coronary heart disease or cardiovascular disease (CVD) in diabetic patients is increasing by 1-3% per year. People with diabetes are more prone to CHD as compared to non-diabetic adults. According to research, more than 100 million people are prone to heart disease, increasing the morbidity and mortality ratio globally. When data of diabetic patients with CHD is compared with non-diabetic patients, it shows that diabetic patients are 1.5 -2.5 times in people assigned male at birth and 2.7-4 times in people assigned female at birth at risk of developing heart disease. The prevalence is higher in women than men.⁵                                                        

Management and treatment of coronary heart disease with diabetes

Lifestyle modification

Lifestyle modification includes proper diet, healthy weight, stress management, smoking cessation, physical activity, and adequate sleep; all these factors play an important role in the management of a healthy lifestyle and reduce the risk of CHD and diabetes. 

To prevent coronary heart disease and diabetes, consume a diet that includes fruits, vegetables, and low-fat products. Maintaining a healthy weight reduces 5-10% chances of getting CHD in diabetic patients. Stress and sleep management are also other important factors because stress and inadequate sleep both can trigger the risk of diabetes and heart diseases. Physical activity and exercise for at least 30 minutes/day or 150 minutes/week are helpful to control CHD and diabetes. Moreover, smoking cessation is also recommended for all patients having diabetes and CHD, providing proper counselling for smoking cessation to patients.⁶

Antiplatelet therapy

Diabetes alters the function of platelets and causes clot formation which leads to coronary heart disease. Therefore, a single or combination of antiplatelet therapy is used to reduce the risk of CHD in diabetic patients. Aspirin, clopidogrel, ticagrelor, and rivaroxaban; are the drugs that are used as antiplatelet therapy. 

Management of blood pressure

Management of elevated blood pressure is necessary to control the severity of diabetes disease and reduce the chances of CHD. The targeted blood pressure in diabetic patients is less than 130/80 mmHg. Treatment with anti-hypertensive drugs initiates when blood pressure is 130/80 mmHg. The choice of drug depends on the patient's condition, severity of disease and comorbid disease. The first line of agents are ACE/ARBs, if it is contraindicated then diuretics, B-blockers, and calcium channel blockers should be considered. However, all drugs must be used with caution.⁶

Control lipid profile

In type 2 diabetes, people are more susceptible to developing cholesterol with high triglycerides, low high-density lipoprotein and increased low-density lipoprotein. Therefore, in type 2 diabetes, individuals are recommended to use statins (atorvastatin) to control further risk of CHD. It shows by studies and data that statin in diabetic patients can reduce the possibility of cardiovascular disorders.⁶

Glycemic control

Controlling blood glucose levels is another major factor in managing and treating CHD because diabetes can increase vascular events (micro or macrovascular). Metformin is the first choice of drug to manage glycemic levels. Other options are sulfonylureas (glimepiride), SGLT2 inhibitors (empagliflozin), and GLP-1 agonists (liraglutide).⁶

Summary

In this article, we thoroughly discuss the connection between coronary heart disease and diabetes. Diabetes and CHD are the most common diseases with a high ratio of morbidity and mortality worldwide. Individuals with diabetes are more prone to develop heart disease because multiple factors in diabetes i.e. insulin resistance, inflammation, obesity, hypertension, and dyslipidemia increase the probability of cardiovascular disorder. Lifestyle modification, and control of blood pressure, glucose level, and lipid profile are important to manage and treat diabetes and further prevent the risk of CHD.