(Reuters Health) - Black people in the U.S. are less likely than whites to take statins recommended to lower their cholesterol, and mistrust of the drugs and of doctors may partly explain the disparity, a recent study suggests.

Even when black patients are prescribed statins, they are more likely than white patients to be prescribed lower doses than experts recommend to get their cholesterol levels under control.

Statin drugs reduce the amount of cholesterol manufactured in the body and how much of it circulates in the bloodstream. Millions of American adults are eligible for statin therapy because they have high enough levels of low-density lipoprotein (LDL), the “bad” cholesterol that builds up in blood vessels and can lead to blood clots and heart attacks.

“We have a wealth of clinical research demonstrating that high LDL cholesterol confers an increased risk of cardiovascular disease and patients at high risk for cardiovascular disease can significantly reduce their risk by taking statins,” said lead study author Dr. Michael Nanna of Duke University Medical Center in Durham, North Carolina.

In 2013, U.S. cardiology groups recommended expanding use of statins to include certain people without a history of heart disease who had some signs they might be at risk for complications like heart attacks in the future - including obesity, smoking, high blood pressure, diabetes, high cholesterol and older age.

Under these guidelines, four groups of people are eligible for statins: adults aged 21 years and older with LDL cholesterol levels of at least 190 milligrams per deciliter of blood (mg/dL); people 40 to 75 years old without heart disease or diabetes with LDL of 70-189 mg/dL and at least a 7.5 percent chance of developing coronary artery disease in the next decade; adults 40 to 75 years old with diabetes and LDL of 70 to 189 mg/dL; and people up to 75 years old who have coronary artery disease.

For the current study, researchers examined data collected in 2015 on 5,689 adults who already had coronary artery disease or had a high risk of developing it in the future.

All of these patients should have been taking statins under current treatment guidelines, researchers note in JAMA Cardiology. But just 75 percent of white patients and 71 percent of black patients took statins.

Most people on statins took doses that were too low, however. Just 33 percent of black patients and 44 percent of white patients were on doses high enough to comply with treatment guidelines for statin therapy.

“There was significant room for improvement in the treatment of both African American and white patients eligible for statin therapy,” Nanna said by email.

When statins are taken at too low a dose, they are less effective at lowering cholesterol. In the study, half of the black patients on statin therapy had LDL cholesterol of 97 mg/dL or less, compared with 85 mg/dL or less for at least half of white people on statins.

Part of the problem may be that black patients are more likely than white patients to mistrust doctors or to believe that statins are unsafe or ineffective, so they refuse statin therapy.

Researchers found that while 94 percent of white patients said they trusted their physicians, only 82 percent of black patients did.

Just 36 percent of black patients in the study and 57 percent of white patients thought statins were safe; only 70 percent of black patients and 74 percent of white patients thought statins were effective.

The study wasn’t a controlled experiment designed to prove which factors explain the racial disparities in statin use.

The study also lacked data on why doctors decided not to prescribe statins or gave patients a lower dose than recommended, the authors note. Side effects including muscle damage lead some patients to discontinue statins.

Even though some doctors disagree about whether all patients covered by statin guidelines should actually be treated with the drugs, the current study offers evidence of under-treatment even in cases where there’s little controversy about the benefits of statins, said Dr. Emily Bucholz, a researcher at Boston Children’s Hospital and Boston Medical Center who wasn’t involved in the study.

“While it is true that statin treatment recommendations have changed in the last decade with some concern for overtreatment, there are a few absolute indications for statin therapy,” Bucholz said by email. “Even among those with known atherosclerotic cardiovascular disease, black patients were less likely to be taking guideline-recommended statins.”

SOURCE: bit.ly/2KwbtH7 and bit.ly/2KqjSsa JAMA Cardiology, online June 13, 2018.