Type 2 diabetes is the most common form of diabetes, usually appearing during middle-age. Obesity and lack of physical activity are two major risk factors associated with the disease. When left untreated, type 2 diabetes can lead to cardiovascular disease and other serious medical problems.

People with type 2 diabetes often have high blood pressure , cholesterol problems , and other risk factors for cardiovascular disease. Commonly, people with type 2 diabetes have high levels of triglycerides and “bad”, or low-density lipoprotein (LDL), cholesterol, and low levels of “good”, or high-density lipoprotein (HDL), cholesterol. These cholesterol problems are associated with the development of fatty buildup in the arteries, or atherosclerosis . People with atherosclerosis are at increased risk for major cardiovascular event, such as a heart attack or stroke .

The American Diabetes Association, the Joint European Societies, and the National Cholesterol Education Program all recommend cholesterol-lowering mediations in people with diabetes whose LDL cholesterol levels are 130 milligrams per deciliter (mg/dL [3.4 mmol/L]) or higher. However, for diabetic patients with lower LDL cholesterol levels, the recommendations are inconsistent, and some diabetes specialists are not convinced that LDL cholesterol levels need to be so low.

A new study in the August 21, 2004 issue of The Lancet found that the use of statins, the most popular and powerful cholesterol-lowering medications, significantly reduced the risk of major cardiovascular events in people with type 2 diabetes and low LDL cholesterol levels.

About the Study

This study included 2,838 people ages 40-75 who had type two diabetes, no history of cardiovascular disease, and at least one of the following cardiovascular risk factors: retinopathy (disorder of the retina in the eye), albuminuria (protein in the urine, a sign of kidney disease), current smoking, or high blood pressure. The participants’ LDL cholesterol had to be 160 mg/dL (4.1 mmol/L) or lower, and was, on average, less than 120 mg/dL (3.1 mmol/L).

Each patient was randomly assigned to receive either a statin medication (atorvastin, 10 milligrams daily) or a placebo pill.

Before the study and at months one, two, three, six, and every six months thereafter, the investigators recorded the participants’ adverse reactions to the study medication and their cholesterol levels. They tracked first-time major cardiovascular event—heart attack, stroke, and surgery to restore blood flow to the heart (coronary revascularization)—and death from any cause. The participants also underwent annual electrocardiograms to evaluate the electrical activity of their hearts.

The researchers used these data to determine whether the use of the statins in these diabetic subjects altered the risk of having a major cardiovascular event or all-cause death.

The Findings

Because it became clear that the statin was more beneficial than the placebo early on in the study, the study was stopped two years earlier than expected. After four years of follow-up, taking the statin medication was associated with a 37% reduction in the risk of first-time major cardiovascular events (83 participants in the statin group and 127 in the placebo group had these events). Specifically, the statin group had a 36%, 48%, and 31% reduction in the risk of heart attack, stroke, and coronary revascularization, respectively. The statin was also associated with a 27% reduction in the risk of death.

Not surprisingly, the statin reduced LDL cholesterol and triglycerides, and slightly increased HDL cholesterol. The participants’ gender, age, cholesterol levels, or other cardiovascular risk factor(s) did not alter the benefits of the statin. The occurrence of adverse events was similar in the statin and placebo groups.

It is important to note that this study was partially funded by Pfizer, the manufacturer of the statin medication used in this trial.

How Does This Affect You?

These findings indicate that statins may benefit people with type 2 diabetes, even when they don’t have high cholesterol. As the authors of this study point out, the substantial reduction in the occurrence of cardiovascular events and all-cause death may warrant broader recommendations for the treatment of people type 2 diabetes with statins.

However, since this study included only people with at least one cardiovascular risk factor and did not include people younger than 45, these findings cannot be generalized to all people with type 2 diabetes. And since this study was relatively short, longer-term studies are needed to rule out adverse events associated with taking cholesterol-lowering medications despite low initial LDL cholesterol levels. Also, left unanswered is why a drugs used to lower LDL-cholesterol level can benefit people with low levels in the first place.

But these results are certainly compelling. As more evidence emerges, physicians will have better tools with which to weigh the risks versus benefits of prescribing statins to patients with low cholesterol levels. It does seem clear from these findings, however, that physicians should, at minimum, adhere to current guidelines recommending cholesterol-lowering medications for type 2 diabetes patients whose LDL cholesterol levels are 130 mg/dL or higher.