Residual risk in statin-treated patients

A 62-year-old man with mixed dyslipidemia, hypertension and type 2 diabetes came to see me after experiencing a myocardial infarction.

His lipid profile one month before his MI was as follows: total cholesterol: 212 mg/dL, triglycerides: 226 mg/dL, HDL-C 32 mg/dL, and LDL-C 68 mg/dL. He was already on maximum dose statin in addition to metformin, pioglitazone, aspirin, and combination angiotensin converting inhibitor/hydrochlorothiazide.

The questions were: why did he have an event while already at LDL-C goal? Does he need additional therapy?

Statins have been demonstrated to reduce CV events in multiple trials. They are the foundation of lipid management and pharmacologic treatment of atherosclerosis. However, statins do not prevent all events. Despite how effective this class of agents is, in high-risk groups as many as 20% to 25% will still eventually experience MI, coronary heart disease death, stroke or revascularization.

There is more to cardiovascular prevention than only prescribing a statin. Blood pressure must be controlled. Patients with diabetes should have glycemic control optimized. Aspirin should be initiated if not contraindicated. Lifestyle factors such as lack of physical activity and tobacco use still need be addressed.

This gentleman’s fasting blood glucose was 112 mg/dL and HbA1C was 6.6%. His blood pressure was 122/80. The urinary microalbumin/Cr ratio was 20. However, non-HDL cholesterol was 180 mg/dL. The non-HDL-C goal should be 30 mg/dL greater than LDL cholesterol goal. In this patient, that would be 100 mg/dL. Additional testing revealed that he had an increased number of small dense LDL particles and increased total LDL particles, not a surprise considering his type 2 diabetes, hypertriglyceridemia and low HDL. His lipoprotein (a) was high 62 mg/dL (<30 mg/dL).

Therefore, in addition to statin, I prescribed niacin 500 mg at bedtime with a plan to increase if tolerated. Niacin is effective in lowering triglycerides, increasing HDL and lowering LDL. Niacin also increases LDL particle size and lowers lipoprotein (a). It is possible for niacin to exacerbate hyperglycemia, but this is mild in most cases. Because he has type 2 diabetes, we will monitor him closely. Had his blood glucoses been less well controlled, I might have chosen a fibrate instead.

Statins are effective. However, in many patients, statin therapy alone is insufficient and additional options must be considered.