The Tayside Diabetes Handbook - Screening And Management Of Cardiovascular Risk

LIPIDS

Hypercholesterolemia is an important reversible risk factor for cardiovascular disease and should be tackled aggressively in all diabetic patients.

• In Type 1 patients, normal or high HDL-cholesterol concentrations are often seen. However an elevated HDL-cholesterol is not associated with the same cardio-protective effect as in non-diabetic individuals.
• The characteristic dyslipidaemia of Type 2 diabetes is mild hypercholesterolaemia, low HDL-cholesterol and hypertriglyceraemia.
• Triglyceride concentrations are elevated by poor diabetic control. Triglycerides may normalise with good diabetic control, attention to diet and increasing exercise. Otherwise drug treatment may be indicated.

Screening for dyslipidaemia: how often & in whom?

• In most cases lipids are checked yearly at the Annual Review.
• Both types of diabetic patients, aged < 70 years (< 75 years if vascular disease present)
• Assess more frequently (3-6 months), if lipid-lowering therapy is prescribed.

Which samples should be assessed?

Total cholesterol, HDL-cholesterol and triglycerides should be requested. For ease, non-fasting estimation is usually adequate.

When sending samples to the Laboratory, it is essential to specify the full lipid request (i.e. Total-cholesterol, HDL-cholesterol and triglycerides) and to state that the patient has diabetes.

Failure to include full details will result in an incomplete report

MANAGEMENT OF LIPIDS - Lifestyle Advice and Secondary Causes

1. Lifestyle Advice

• Reinforce dietary advice and optimise glycaemic control.
• Provide weight reduction diet for those with BMI > 25.
• If BMI > 30, set target of 5-10 kg weight loss.
• Increase fruit and vegetable consumption (5 portions per day).
• Increase oily fish consumption (2 portions per week).
• Reduce saturated fat intake.
• Encourage regular exercise

2. Exclude (and Treat) Secondary Causes of Hypercholesterolaemia

• Hypothyroidism
• Nephrotic Syndrome
• Cholestasis
• Drugs (e.g. diuretics, corticosteroids)

MANAGEMENT OF LIPIDS: Secondary Prevention Lipid Treatment

3. Drug Treatment: Patients with existing cardiovascular disease (Secondary Prevention)

Includes diabetic patients with angina, myocardial infarction, cerebrovascular disease and peripheral vascular disease

• Treat with a 'Statin' if Total cholesterol > 5 mmol/L
• All patients should receive Aspirin, unless contraindications present

MANAGEMENT OF LIPIDS - Primary Prevention Lipid Treatment

4. Drug Treatment: Patients without cardiovascular disease (Primary Prevention)

An aggressive approach to lipid lowering is recommended in all diabetic patients due to their underlying risk of developing coronary heart disease.

• Type 1 and Type 2 patients with evidence of nephropathy (microalbuminuria or proteinuria present) should be regarded as candidates for secondary prevention. Treatment with a 'Statin' is recommended if Total cholesterol >5 mmol/L
• Consider this approach also in Type 1 patients with a family history of premature ischaemic heart disease
• In all other patients, the absolute risk of developing CHD over 10 years may be calculated using the Joint British Coronary Prevention Chart (see Cardiovascular Risk Calculator).
• Treatment with a 'Statin' is recommended when the 10 year risk of an event is > 30%
• Consider treatment at a lower risk threshold (e.g. 15-30% risk) in Type 1 patients without nephropathy, as true CHD risk may be under-estimated by the chart
• The Joint British Chart does not take into account a family history of premature CHD. Where this is relevant (i.e. 1St degree male relative affected before age 55 or female before age 65), multiply the risk of an event by a factor of 1.5 to obtain a more accurate assessment.
• Consider adding Aspirin in patients who display sufficient risk to warrant lipid-lowering therapy

Assessment of absolute CHD risk may be performed using the Joint British Coronary Prevention Chart. Intervention with a Statin is recommended if 10 year risk of an event is >30%