Introduction
Type 2 diabetes mellitus (T2DM) is well-known to be linked to higher cardiovascular morbidity and mortality. The risk of coronary heart disease, ischemic stroke, and mortality increases two to four times in Type 2 diabetes mellitus patients. T2DM affects life quality and expectancy by increasing the risk of heart failure, peripheral arterial insufficiency, and microvascular complications. According to estimates, people with diabetes typically have a life expectancy reduction of four to eight years compared to people without the disease.
As per previous studies, it was concluded that patients with diabetes have a two to four times higher risk of cardiovascular morbidity and mortality than people without diabetes. However, recent studies have concluded that the risk may not be as high as previously thought if the patients do not have any other systemic or coronary diseases. Patients with diabetes for less than ten years without other risk factors are at a much lower risk compared to those with associated risk factors like conventional cardiovascular risk factors or established coronary artery disease.
How Are High-Risk Patients for Diabetes With Cardiovascular Risks Identified?
-
Age - The most significant risk factor for coronary heart disease, which cannot be modified, is age. With age, the risk of cardiovascular diseases increases in both men and women. According to the studies, a transition to a high-risk category for cardiovascular disease appears to take place at a specific age for both genders. Therefore, a person with diabetes must be under 35 years old for men and 45 years old for women, respectively, and there must be no other risk factors or signs of cardiovascular disease for them to be considered at low risk, which is defined as less than ten percent risk estimate in ten years. Therefore, patients over these age ranges should be the focus of the majority of efforts to reduce events.
-
Gender - According to the studies, the risk of myocardial infarction, both in the general and diabetic population, is higher in men than in women. However, the mortality rate is higher for women with diabetes along with coronary disease.
-
Family History - Diabetic patients having a family history of CHD are at a greater risk of developing cardiovascular complications.
-
Smoking - Smoking is one of the greatest contributors to cardiovascular risks. In patients with diabetes, active smoking is linked to the highest risk of total mortality and cardiovascular events, whereas quitting smoking is linked to a lower risk of total mortality and cardiovascular events in patients with diabetes.
-
Hypertension - A known risk factor for CHD and stroke mortality is hypertension. Diabetic patients often suffer from hypertension, and thus patients with diabetes along with hypertension are always more prone to developing cardiovascular complications and hence are considered high-risk patients.
-
Lipids in the Blood - Low-density lipoproteins (LDL) or the presence of bad cholesterol in diabetic patients make them more prone to cardiovascular complications.
What Are the Conditions Categorized as High-Risk for Diabetic Patients?
-
Early Age and Long Duration of the Disease - The length of diabetes is a significant factor in determining the risk of CHD and cardiovascular disease. Patients who have had diabetes for more than ten years may be at increased risk. According to the studies, it was also found that an early onset of diabetes makes a patient more prone to cardiovascular risks.
-
Decreased Glomerular Filtration Rate - An independent risk factor for the onset and severity of coronary artery disease is the glomerular filtration rate (GFR). Both proteinuria and decreased glomerular filtration rate separately raises the risk of cardiovascular disease for diabetic patients.
-
Metabolic Syndrome - According to a study, diabetic patients with metabolic syndrome have a higher risk of developing cardiovascular disorders.
-
Increased Hypoglycemia - The risk of cardiovascular disease increases by about two fold in T2DM patients who experience severe hypoglycemia (SH), which is defined as a hypoglycemic episode requiring assistance.
-
Non-alcoholic Fatty Liver - Among patients with T2DM, non-alcoholic fatty liver disease is a separate predictor of CAD (coronary artery disease).
-
Obstructive Sleep Apnea - It is defined by recurrent episodes of partial or complete upper airway collapse and obstruction while asleep. It is also characterized by intermittent oxygen desaturation, sleep fragmentation, and an increased risk of fatal myocardial infarction and stroke. Hence, diabetic patients with obstructive sleep apnea are at a higher risk of developing cardiovascular disorders.
What Are the Results of Clinical Trial Studies for Assessing Cardiovascular Risk in Diabetic Patients?
The statement “Diabetes is a cardiovascular risk equivalent” was based on a study conducted in Finland that found that Type 2 diabetes mellitus (T2DM) patients without coronary heart disease (CHD) events had similar rates of coronary mortality to non-diabetic patients with a history of coronary events. Diabetic patients with CHD have the worst prognosis due to an increase in coronary death rates.
Recent research shows that the risk of CHD in people with T2DM is highly heterogeneous and cannot always be compared to the risk in people with prior cardiovascular disease. A meta-analysis of 13 epidemiological studies, which included 45,108 patients with and without diabetes, found that the risk of CHD was 43 percent lower in T2DM patients without a history of myocardial infarction when compared to non-diabetics. The risk of CHD was significantly lower among patients with T2DM without CHD than in those with CHD without diabetes in a large population-based cohort of 1,586,061 adults aged 30 to 90 years who were followed up for ten years.
The 2016 ADA (American Diabetes Association) standards of diabetes care, the 2013 ACC/AHA guidelines (American College of Cardiology and American Heart Association), the Brazilian Diabetes Society guidelines, and the 2016 European Society of Cardiology (ESC) guidelines no longer regard diabetes as an equivalent coronary risk.
Conclusion:
Newly developed guidelines do not consider diabetes as having an equivalent cardiovascular risk. These new studies consider categorizing diabetic patients into cardiovascular risk groups for primary prevention. The categorization of diabetic patients helps improve the precision of predicting future cardiovascular events, silent ischemia, and subclinical coronary artery disease (CAD). It also helps to differentiate between high and low-risk patients, as some of the high-risk patients may require statin or Aspirin for treatment, and treatment can be avoided in low-risk patients. Additionally, it may enable the clinician to choose whether to step up risk reduction efforts using newer glucose-controlling medications like SGLT-2 inhibitors or GLP-1 agonists, which have recently demonstrated additional cardiovascular protective effects. The understanding that not all people with diabetes mellitus (DM) are coronary heart disease risk equivalents is a significant step forward, even though the data currently available are insufficient to suggest any changes in treatment recommendations.
