DIABETES; Medical point of view
Diabetes and cardiovascular complications
What is diabetes?
Diabetes is a metabolic disorder that affects the way the body uses sugar, which is the essential fuel for the proper functioning of the body's cells. For the sugar in the blood to be transferred to the cells, the body needs insulin, which is the most important hormone the pancreas produces.
When there is an insufficient quantity of this hormone (insulinopenia) or an inadequate response to its mechanism of action (insulin resistance), sugar accumulates in the blood, causing sustained hyperglycemia. This buildup is known as diabetes.
Although there are several categories of diabetes, we will focus on type 2, which affects nearly 90% of all people with diabetes.
Diabetes and epidemiology
This disease is spreading worldwide and is continually on the rise. In 2017, it was estimated that approximately 1 in 11 adults had diabetes. The number of people with diabetes will increase from 425 million to an estimated 645 million between 2017 and 2045, a significant 50% increase.
Contrary to type 1 diabetes, type 2 occurs later on in life, most often in middle-aged persons and seniors. People most likely to develop type 2 diabetes have a family history of diabetes, are overweight or obese, and have other metabolic risk factors. However, with widespread obesity cases among young people, many children and teenagers are affected with type 2 diabetes at an early age.
Diabetes means cardiovascular disease. Indeed, one of the heaviest burdens of diabetes is the development of cardiovascular complications that damage the heart and blood vessels.
In 2 cases out of 3, death in diabetic patients is attributable to cardiovascular disease. There is a strong correlation between diabetes and the development of coronary heart disease affecting the coronary arteries, which feed the cardiac muscle or myocardium.
It is on account of the above reasons that it is extremely important to take a diabetes diagnosis very seriously from the very beginning to avoid any morbid consequences or even death.
Other aspects of diabetes and their impact on certain body organs are not discussed here, but we briefly mention the risks of cerebrovascular accidents (CVA) or stroke, kidney disease referred to as Diabetic Nephropathy, an eye condition that can cause vision loss Diabetic Retinopathy, neurological complications, and lower limb amputations. The list goes on...
A diagnosis of cardiovascular complications is reached based on the patient's responses to the physician's questions during an office visit. This information is used to identify symptoms of poorly-controlled diabetes, such as excessive thirst, frequent urination, blurred vision, or abnormal weight loss or gain.
These changes in bodily functions are often due to an unhealthy diet and a lack of physical activity or to other poor lifestyle habits. Likewise, the diagnosis is made by taking a close look at other cardiovascular risk factors other than diabetes, namely high blood pressure and cholesterol and/or the presence of high levels of triglycerides (fats) in the blood.
In addition, a thorough physical exam is performed to look for direct diabetes complications and their repercussions on the cardiovascular system, namely any swelling due to excess fluid in a body part.
Confirmation of diabetes diagnosis is made after the patient has a fasting or random blood sugar test as well as a glycated hemoglobin (HbA1c) test, which reflects the level of sugar stored in the body during the last 3 months.
Diagnostic screening for cardiovascular disease is conducted, based on clinical relevance, using one or more of the following tests:
- electrocardiogram (ECG);
- lung X-ray;
- cardiac ultrasound;
- serum measurement of stress markers on myocardial cells (BNP or NT-ProBNP);
- invasive or non-invasive imaging (cardiac catheterization) to assess the presence of a coronary blockage requiring pharmaceutical intervention, and/or using a percutaneous invasive solution with catheters or surgery.
Cardiovascular complications and symptomatology
To better understand the interdependence between diabetes and cardiovascular disease, a simple way to see the spectrum of clinical diseases is to measure their influence on the pump (the heart), the circuits (the blood vessels), and the body filters (the kidneys).
If the heart pump fails secondarily to diabetes, the patient is at risk of developing symptoms of heart failure. In this case, the pump is not able to perform its normal function, which is to propel blood to the body organs and thus unclog the pulmonary vessels of their blood content.
This results in symptoms of breathing difficulty, at first during exercise, and progressively at rest as well.
Patients may also complain about swollen feet, loss of appetite, fatigue, and decreased need to urinate, which is due to a reduction in the kidney’s ability to remove fluids.
There are 2 types of cardiac insufficiency or heart failure in diabetic patients: the first anomaly occurs when the lower heart chambers do not relax as they should (diastolic dysfunction); the second one affects the heart's capability to contract and eject blood (systolic dysfunction).
Diabetes causes heart failure either by a direct impact on the heart muscle or through the disease affecting the coronary arteries.
In addition, the involvement of blood vessels is another predominant complication of diabetes. In this case, the circuits are unable to adequately deliver blood to the various body organs.
The body is affected at several levels
It should be noted that cardiovascular and cerebrovascular complications of diabetes are as follows, in descending order of prevalence: peripheral vascular disease, heart failure, myocardial infarction, stroke, and cardiac-related deaths.
Strategies to be adopted
Diabetes is a very heavy burden to bear and calls for appropriate strategies to be developed: on the one hand, prevention, and on the other, as soon as a person is diagnosed with this metabolic disorder, he/she should get treatment immediately.
Kidney involvement with diabetes (type 1 and type 2), is a common complication that can be severe and lead to end-stage renal failure. In medical terms, it is called diabetic nephropathy.
The first cause of renal disease
In North America, diabetic nephropathy is the first cause of renal disease. The mechanism by which hyperglycemia (high levels of sugar in the blood) destroys the kidneys is currently the subject of extensive international studies. The research work bears on identifying and elucidating the reasons behind this serious renal complication and eventually minimizing its long-term harmful effects on the body.
At present, we know that diabetes induces the production of metabolites (sugar breakdown substance), which, through inflammation and fibrosis, cause progressive deterioration of the kidneys.
Different types of renal manifestations
Renal manifestations in diabetes are varied.
They can be benign or severe and amplified by hereditary traits influenced by genes and several other modifiable or non-modifiable risk factors. Here, we will mainly consider the following: age, ethnic origin, socioeconomic status, obesity or unexplained weight loss, smoking habit, sleep apnea, and high blood pressure.
The first sign of kidney damage
The first indication of kidney damage is the appearance of albuminuria (a high amount of albumin, a protein, in urine). The early stage of the disease is usually asymptomatic, it is detected only by routine tests requested by the treating physician.
At a more advanced stage, we note the onset of high blood pressure, nephrotic syndrome (a significant loss of protein in the urine), and swelling of the legs, ankles, and feet or sometimes generalized, as well as progressive deterioration of kidney function that will spread over several years.
Various symptoms at the terminal stage
At the terminal stage of the disease, patients will develop uremia, which is the accumulation of waste products in the blood that are not eliminated. Uremia symptoms are as follows:
- nausea and vomiting,
- generalized itching,
- encephalopathy, damage that affects the brain.
It is at this stage that dialysis, an extracorporeal purification technique, will be used to replace kidney function.
The first step in treatment is the management of the diabetic condition itself. Sugar levels must be optimally controlled to avoid the complications mentioned above. In a simple and general way, treatment is based on the following principles:
- hemoglobin A1c: a value of <7% of glycated hemoglobin should generally be targeted;
- blood pressure: regular monitoring for 110-120/80 mm Hg;
- cholesterol: lipid balance, which is the amount of fat in the blood, should meet the standard set specifically for people with diabetes.
Reaching therapeutic goals
Some of the therapeutic goals are attainable with lifestyle changes that include the regular practice of physical activity and eating a healthy balanced diet, in compliance with Canada's Food Guide. Other changes of equal importance are giving up smoking and losing weight, if applicable.
Blood sugar level
Good glycemic control (glucose/sugar level in the blood), and attaining targeted values require, in most cases, taking medication along with the essential above lifestyle modifications.
The first line of treatment consists of taking a drug (metformin) that improves the effectiveness and sensitivity of insulin receptors in the body. The action of insulin on the use of sugar by the cells is then amplified.
In addition to the therapeutic weaponry
Fortunately, in addition to metformin, we now have newer anti-diabetic drugs that have cardiovascular benefits as well. The groups of drugs we refer to are as follows:
inhibitors SGLT2: empagliflozin, dapagliflozin, and canagliflozin.
Numerous molecules of this drug class proved their worth in clinical studies. Not only did this type of medication lower hypoglycemic thresholds, but it also decreased the number of hospitalizations due to heart failure, deaths of cardiac origin, infarctions, and strokes. In so doing, these inhibitors have significantly improved the patient’s quality of life.
The main mechanism of action of these drugs is to increase the amount of sugar excreted in the urine.
SGLT2 inhibitors proved to be just as effective in the case of diabetic patients as for those whose blood glucose levels were normal but had a cardiac condition, renal failure, or other similar complications.
GLP-1 agonists: emaglutide, liraglutide, duraglutide, etc.
These molecules intensify the effect of insulin. They proved their efficacy in monitoring glycemic levels in diabetic patients and the reduction of cardiovascular events as well.
More helpful medication
Aside from glycemic control, other drugs proved to be effective in the case of high blood pressure, that is to say above the targeted 110-120/80 mmHg value. We are referring to:
- angiotensin-converting enzyme inhibitors (ACEI),
- angiotensin II receptor blockers (ARBs).
Their effectiveness is perceptible at the renal level. They protect from diabetic nephropathy, and lower the number of cardiac events, particularly in the presence of reduced cardiac capacity in injecting blood (systolic cardiac dysfunction) or after myocardial infarction.
A major challenge
There is no doubt that diabetes remains a huge therapeutic challenge with its multiple complications, especially those that affect the cardiovascular system.
However, with proper treatment and proactive management, involving the patient directly in the care and understanding of his/her disease, these morbid and fatal complications can be prevented.
Diabetes has become an epidemic without borders. Society can and must work to curb the progression of diabetes as it is currently evolving, both locally and globally.
Public awareness of the health, social and economic issues surrounding diabetes is essential.
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