Statins Linked With Type 2 Diabetes Progression, Study Suggests

Statins are a powerful tool for lowering high cholesterol and reducing serious heart events — including for people with type 2 diabetes. But a new study suggests that people with type 2 diabetes need to weigh these benefits against the risk that statins may make their blood sugar harder to control.

For the study, published October 4 in JAMA Internal Medicine, researchers examined data on 166,000 people who received care through the Veterans Affairs health system and were diagnosed with type 2 diabetes between 2003 and 2015. Half these individuals started treatment with statins during the study period, and the other half did not.

Diabetes progression, including dangerous spikes in blood sugar or the need for new medications to manage blood sugar, occurred with about 56 percent of participants on statins, compared with 48 percent of people who didn’t use these cholesterol-lowering pills.

Overall, statin users were 37 percent more likely to experience diabetes progression. The subset of participants on more intensive statin therapy designed to achieve more aggressive reductions in cholesterol levels had an 83 percent greater likelihood of diabetes progression.

When researchers looked at individual components of diabetes progression, they found statins associated with a 41 percent higher likelihood of treatment with new medications to lower blood sugar, a 16 percent greater chance of starting insulin therapy, 13 percent steeper odds of developing consistently high blood sugar, and a 24 percent increased risk of uncontrolled diabetes or a serious complication known as ketoacidosis, which happens when acids accumulate in the blood.

These risks don’t necessarily mean that people with type 2 diabetes need to halt statin therapy or avoid starting treatment, says the study's lead author, Ishak Mansi, MD, a staff internist at the VA North Texas Health System and a professor at the University of Texas Southwestern Medical Center in Dallas.

Statins for ‘Primary’ vs. ‘Secondary’ Prevention

But these risks do suggest that people prescribed statins would benefit from having a frank discussion about the risks and benefits of these medications, Dr. Mansi says. That’s particularly true for people with type 2 diabetes who don’t have a history of cardiovascular disease, he adds. Roughly three in four patients on statins in the study didn’t have a previous heart problem.

“We have to differentiate between using statins for primary prevention of cardiovascular diseases — that is, in patients who never had any cardiovascular disease previously — and those using statins for secondary prevention: those who have preexisting cardiovascular disease,” Mansi says.

In the latter group, “statins are one of the most important lines of treatment, and their benefits are great,” he says. More research is needed to determine if statin therapy is best reserved only for people with type 2 diabetes who already have cardiovascular disease or a history of heart attack or stroke, Mansi adds.

The study wasn’t a controlled experiment designed to prove whether or how statins might directly cause diabetes progression. It’s possible that statins interfere with processes that control how well the body produces and uses insulin, a hormone critical for maintaining healthy blood sugar levels, the study team notes in the paper.

The Study Doesn’t Prove a Link Between Statin Use and Diabetes Progression

One limitation of the study is the potential for diabetes progression to be detected more often among statin users simply because these patients have more frequent checkups than people who aren’t on statins, the study team points out.

Still, the findings offer fresh evidence of a potential risk statins pose for people with type 2 diabetes. The U.S. Food and Drug Administration in 2012 required drugmakers to add a safety warning to the labels of all statins indicating the potential of these drugs to raise blood sugar.

Overall, the risks of high cholesterol — including heart attacks, strokes, and deaths from cardiovascular disease — are serious enough that patients should still consider statins if their cholesterol isn’t in a healthy range, regardless of the person's heart health history, says Connie Newman, MD, an adjunct professor at the New York University Grossman School of Medicine in New York City who wasn’t involved in the new study.

Statins Help Reduce Heart Risks in People Diagnosed With Diabetes

According to Johns Hopkins Medicine, people with diabetes are two to four times more likely to develop cardiovascular disease than people without diabetes, and cardiovascular disease is the most common cause of death in people with diabetes.

Research has long shown that statins reduce heart risks among people with type 2 diabetes. For example, one study published more than a decade ago in Diabetologia examined the effect of statins on 589,091 people with type 2 diabetes. Before statin therapy, 94 percent of them had at least a 10 percent chance of experiencing an event like a heart attack or stroke in the next decade. After four months on statins, the proportion with this level of cardiovascular risk dropped by 7 percent.

“People with diabetes should definitely take statins, because the benefits of statins in terms of reducing cardiovascular events far exceeds any potential risk of the statin,” Dr. Newman says.

As for people without type 2 diabetes, concern about developing this condition shouldn’t stop them from taking statins, either, Newman adds.

“Statins increase the risk of newly diagnosed diabetes in a small percentage of patients,” Newman notes. “However, studies show that those patients who develop diabetes have multiple preexisting risk factors for diabetes, such as prediabetes and metabolic syndrome, and would generally develop diabetes in the long term even if they didn’t take statins.”

Learn more about statin therapy in Diabetes Daily's article "Diabetes and Statins."