Prescribing statins - current concepts

What is the dose of statin that should be prescribed to patients who have clinically evident coronary artery disease?

When a patient below the age of 75 years has evidence of coronary artery disease, statins in appropriately high doses should be prescribed irrespective of their serum cholesterol values. A high dose (or intensive dose) for Atorvastatin refers to 40 to 80mg per day; a similar dose for Simvastatin is 40mg per day.

Is the dose of statin prescribed to a patient determined by the LDL - cholesterol value?
The new 2013 cholesterol lowering guidelines tell us that the decision to start a statin can be determined, in part, by the LDL cholesterol level. But the dose (high intensity versus moderate intensity) is determined by parameters other than the LDL cholesterol value. 

When should serum creatine kinase (CK) be tested when patients are on statins?

CK needs to be tested only when patients on statins complain of muscle pain or muscle weakness.

How can muscle pain due to statins be differentiated from other causes of myalgia?

Myalgia due to statins will resolve within 2 weeks of stopping the drug. When muscle pain persists beyond 2 weeks after discontinuing statins, other causes of myalgia must be considered.

Should liver function tests be done routinely when patients are on statins?

No. It is not necessary.

Should all patients with diabetes be prescribed with a statin?

All diabetic patients between the ages of 40 and 75 years should generally receive a statin unless their LDL cholesterol level is unusually low (below 1.8mmol/L). Whether low dose (moderate intensity) or high dose (high intensity) statins are needed should be decided by their 10-year risk of developing atherosclerotic coronary artery disease.

Is there any role for the combination of a statin with a non-statin (fenofibrate / gemfibrosil / nicotinic acid)?

Yes. There is definite evidence for doing so in patients with familial hypercholesterolemia because the reduction in cardiovascular risk is proportional to the degree of lowering of LDL cholesterol. The diagnosis of familial hypercholesterolemia should be suspected in patients with LDL cholesterol levels more than 4.9mmol/L (190mg/dL). Whether there is a benefit in combining a statin with a non-statin for those with diabetes and coronary artery disease is still not clear. When a statin is combined with a fibrate, it is better to use fenofibrate (and not gemfibrosil) because it is safer.

Can statins be continued during pregnancy?
Statins and non-statin cholesterol lowering drugs are classified as pregnancy category X and should not be taken during pregnancy and while breast feeding. Those who are on statins should discontinue them 2 to 3 months before becoming pregnant. 

Is there an increased risk of new-onset diabetes due to statin therapy?
Yes, but the risk is modest. With low dose statin therapy, 1 out of 1000 will develop diabetes per year. With high dose statin therapy, 3 out of 1000 will develop diabetes per year according to available evidence. On the other hand, appropriately used statin therapy prevents 5 to 6 cases of atherosclerosis induced vascular disease per 1000 population per year. 

Is there any role for using statins for primary prevention in individuals who are younger than 40 years of age if they do not have diabetes or heart disease?
Yes, in selected individuals. Young people who have risk factors like: a strong family history of premature coronary artery disease, an LDL cholesterol more than 4.1mmol/L (160mg/dL), a high sensitivity CRP level more than 2mg/L, or a coronary calcium score more than 300units can be considered for statin therapy as primary prevention. Moderate intensity (lower dose) statins are recommended if their calculated lifetime risk of developing coronary artery disease is not high. High intensity statin therapy is recommended if the calculated lifetime risk is high.

How are the statins different from each other in their LDL- cholesterol lowering ability?
When statins are evaluated based on their ability to lower LDL cholesterol, we note that 5mg of Rosuvastatin is equal to 10mg of Atrovastatin is equal to 20mg of Simvastatin is equal to 40mg of Lovastatin. The relationship between dose of statin and degree of LDL-cholesterol lowering is not linear: doubling of a statin dose does not double the fall in LDL cholesterol, but only an extra 6 percent fall will be seen.

Based on the 2013 cholesterol lowering guidelines from the American Heart Association and the prevention guidelines clinical vignettes .