Diabetes and Atherosclerosis

Diabetes and Atherosclerosis

Dr. S.M.Sadikot.
Hon. Endocrinologist,
Jaslok Hospital and Research Centre,
Mumbai 400026

Patients with diabetes have an increased prevalence of factors known to increase the risk of cardiovascular disease (CVD) -- dyslipidemia, hypertension and obesity especially central obesity (raised waist to hip ratio). In fact, this triad along with diabetes is the integral part of the "Metabolic" Syndrome or Syndrome X as it is called.

Thus, the prevalence of atherosclerosis is increased manifold in people with diabetes, occurs earlier in life, progresses faster to the more sever forms and is associated with an increased chance of death from these complications. CVD takes a high toll in patients with diabetes. Leaving aside the morbidity, atherosclerotic macrovascular disease and its complications account for more than half of the deaths in patients with type 2 diabetes.

Coronary and cerebral artery disease is 2-4 times as common in a person with diabetes and whilst vascular blocks in the legs (peripheral vascular disease) is 4-6 times more common.

It is widely accepted that when a person's risk for getting a myocardial infarct is estimated, if one has already suffered from an infarct, the risk for getting another infarct becomes extremely high. Diabetes itself is considered so major a risk factor that it is on par with having suffered an infarct. Put simply, if one has diabetes ( but has not suffered an infarct), the risk for getting an infarct is the same as that of a person who may not have diabetes but has already had one episode of myocardial infarct!

Not only is diabetes itself a major factor in causing damage to the endothelium, people with diabetes are prone to show other risk factors which themselves can damage the inner linings of the arteries. In the presence of high blood glucose levels, the potential of these other risk factors to cause atherosclerosis is increased manifold.

Risk Factors for Cardiovascular Disease in Patients with Diabetes Modifiable major risk factors

  • Uncontrolled and high blood glucose levels
  • High blood pressure
  • High cholesterol levels, especially the "bad" LDL-cholesterol levels which are above 100mg%
  • Low levels of the "good" HDL-cholesterol (below 45mg%)
  • High levels of triglycerides in the blood (more than 150mg%)
  • Obesity, especially "central"obesity with a high waist-hip ratio
  • Sedentary lifestyle with little or no exercise
  • Presence of kidney disease as judged by albumin in the urine
  • Raised levels of insulin in the blood
  • Smoking, or the use of tobacco in any form, Predisposing risk factors
    • Genetic factors (family history)
    • Age of the patient
    • Duration of diabetes

Whilst, it may not be possible to change your patient's genes or age, there are many factors which can be modified and it is essential that all efforts be made to screen for these risk factors and take appropriate action.

1) A comprehensive clinical history and examination for the presence of coronary heart disease, or cerebrovascular, or peripheral vascular disease; this includes questions about previous angina. TIAs, intermittent claudication, established myocardial infarction etc.

2) Family history for premature coronary artery disease.

3) A complete physical examination for cardiac function, presence or absence of peripheral pulses, presence of bruits, evidence of peripheral and / or cerebral ischemia.

4) Blood pressure recordings.

5) Height and weight (BMI) and waist-hip ratio

6) Lipid profile this profile should include, estimation of serum triglycerides, serum total cholesterol, HDL-cholesterol and calculated LDL cholesterol although preferable to do in a fasting state, may be done with a random sample, and the values confirmed in the fasting stage, if abnormal.

7) Estimation for the presence of microalbuminuria in those who are dipstick (albustix) negative;

8) History of tobacco use.

9) Standard resting 12 lead ECG; sensitivity of the standard 12 lead resting ECG is moderate and cannot rule out the possibility of clinically significant disease.

Further investigation would depend on individual circumstances and degree of clinical suspicion.

It is while recalling that most of these investigations would in any case be carried out on all patients with diabetes and so would not mean an additional expense to the patient.

As one can see from the modifiable factors above, optimal management of the blood glucose levels and the associated conditions found so frequently in a patient with diabetes such as hypertension and dyslipidemias should be tightly controlled. All these aspects have been dealt with in detail in separate chapters, as has the need to increase physical activity, which has been dealt with in the chapter on exercise.

Recent studies have shown that there is a significant lacunae in the use of aspirin prophylaxis as a primary prevention strategy for patients 30 years of age or older with type 2 diabetes who have risk factors for CVD. Secondary prophylaxis with aspirin in patients with established CVD has been shown to reduce the risk of cardiovascular complications. Secondary prophylaxis is indicated in diabetic men and women with evidence of large vessel disease. This includes patients with a history of myocardial infarction, vascular bypass procedure, stroke or transient ischemic attack, peripheral vascular disease, claudication or angina.

Consider primary prevention in high-risk diabetic men and women age 30 or older; this includes persons with the following risk factors:

  • Family history of coronary heart disease
  • Cigarette smoking
  • Hypertension
  • Obesity (>120 percent desirable body weight); BMI >25
  • Albuminuria (micro or macro)
  • Cholesterol >200 mg per dL (5.17 mmol per L)
  • LDL cholesterol >130 mg per dL (3.36 mmol per L)
  • HDL cholesterol <40 mg per dL (1.03 mmol per L)
  • Triglycerides >250 mg per dL (2.82 mmol per L)

Dosage recommendations range from 75 mg to 325 mg per day. The principal risks of aspirin therapy include gastric mucosal injury and gastrointestinal hemorrhage. Minor bleeding episodes may occur at low dosages. Contraindications to aspirin include allergy, tendency for bleeding, anticoagulant therapy, recent gastrointestinal bleeding and clinically active hepatic disease. Ticlopidine and recently clopidogrel have also been used either by themselves or with aspirin. But most studies still maintain the primacy of aspirin usage and this would also be so if one were to consider the cost aspects of the three drugs, namely, aspirin, ticlopidine and clopidogrel.

The point which has to be made is that the use of these drugs should be considered in all patients with diabetes unless there are definite contra-indications for their use.

Finally, and very importantly, all efforts must be made to stop the patient from smoking or using tobacco in any form. The importance of this can, and should, never be minimized and continued vigilance needs to be kept to maintain compliance.