Evidence supports the need to aggressively treat dyslipidemia in patients with diabetes, in order to reduce cardiovascular disease (CVD).
By Shelley Diamond, BScPhm
Illustration by Martin Bregman
The incidence of vascular disease is two to four times higher for those living with diabetes, compared to those without the condition. Cardiovascular disease is the primary cause of death for people with type 1 and type 2 diabetes.
People living with diabetes typically have an increase in triglycerides (TG), decreased high-density lipoprotein cholesterol (HDL-C), and an increase in small dense low-density lipoprotein (LDL), a lipoprotein particle that may be particularly atherogenic. Low-density lipoprotein cholesterol (LDL-C) is relatively normal in patients with diabetes, but non-HDL (non HDL = total cholesterol minus HDL-C) and apolipoprotein B (apo B) are increased. These last two markers have been shown to have a higher correlation with cardiovascular events than LDL.
There should be a fasting lipid profile at the time of diagnosis and then annually or as clinically indicated. More frequent testing can be done if treatment is initiated. Since fasting can be a challenge for people with diabetes, the Canadian Diabetes Association guidelines suggest that non-HDL or apo B measurements be considered since fasting is not required for these tests. Recent recommendations also suggest there is minimal difference between fasting and non-fasting HDL, LDL, and total cholesterol levels, and this may improve test adherence and reduce the risk of hypoglycemia.
Highlights from dyslipidemia treatment studies
- Statin use should be considered for any person at risk of a vascular event. The Heart Protection Study emphasized the benefits of statin treatment irrespective of the pre-existng LDL-C level.
- The Collaborative Atorvastatin Diabetes Study supports that treating “normal” LDL-C levels in people with type 2 diabetes and no known vascular disease benefits in reducing the risk of a first CV event. Therefore this study challenged the use of a particular threshold level of LDL-C as the main indication of which individuals with type 2 diabetes should receive statin therapy.
- For those with stable coronary artery disease, the Treating to New Targets trial showed that those treated with atorvastatin 80mg daily who achieved a mean LDL-C of 2.0mmol/L, had 25% fewer major CVD events.
- The Cholesterol Treatment Trialists Collaboration found that for every 1.0mmol/L reduction in LDL-C, there was an approximate 20% reduction in CVD events, regardless of baseline LDL-C.
- Several studies have shown that fibrate therapy may help reduce the microvascular complications associated with diabetes (e.g. retinopathy, nephropathy).
Current recommendations for treatment
- A statin is recommended for:
- Patients with diabetes > 40 years of age*
- Patients > 30 years of age who have been living with diabetes for > 15 years
- Patients < 40 years of age with signs of microvascular disease (retinopathy, nephropathy)
- Patients with clinical macrovascular disease
- Treatment should be initiated to achieve LDL-C ≤ 2.0 mmol/L
- Fibrates or niacin are not indicated for those achieving the above LDL-C goal
- For those not achieving target, a combination of statin therapy with a second-line agent may be used
- For those who have a TG > 10 mmol/L, a fibrate should be used to reduce the risk of pancreatitis
*based on Heart Protection Study (HPS) and Collaborative Atorvastatin Diabetes Study (CARDS)
Talking to your patients about lifestyle is essential since there are many modifiable dyslipidemia risk factors, including:
- Poor glycemic control
- Sedentary lifestyle
- Poor dietary habits
- Abdominal obesity
- Medication non-adherence
There are lots of interventions and only so much time available with your diabetes patients. Discussing management of dyslipidemia may well be the most impactful one!