Those taking statin medications to lower cholesterol need not reduce levels to any specific point, rather they just need to take the correct dose, according to newly released recommendations from the American College of Cardiology and the American Heart Association, The New York Times reports. This news is of particular relevance to people with HIV, who have a raised risk of high cholesterol.

However, these guidelines have run into immediate trouble as news has surfaced that the online risk calculator people can use to determine if they should take statins may be flawed, far overestimating risk. Steven Nissen, MD, chief of cardiovascular medicine at the Cleveland Clinic and the former president of the ACC, has even called to block the new guidelines as a result.

The new guidelines stipulate that those who have a high risk of heart attack or stroke—because they have a condition such as diabetes, have an LDL (“bad”) cholesterol level of 190 or above, or have had a heart attack before—should in almost all cases take a statin. The traditional directive for them to bring their LDL levels down to 70 has been removed from the guidelines. In the past, clinicians may have prescribed additional drugs, for example the cholesterol absorption inhibitor Zetia (ezetimibe), to those who failed to lower their cholesterol sufficiently; this is no longer advised as there is no evidence that such medications prevent heart attacks or strokes.

Statins should be considered for someone who has a 7.5 percent or higher risk for a heart attack or stroke over the next decade. Among the contributing factors to this risk calculations are blood pressure, age and total cholesterol level.

Adding stokes to the risk calculations is new and should open up the possibility for new groups of people to receive statins.

As for the online calculator, the source of its troubles may have been the use of outdated health data from the 1990s in creating a mathematical model to predict how risk factors might lead to a heart attack or stroke. The problem is that health demographics have already shifted significantly since that decade: Smoking prevalence has dropped, and people tend to have strokes and heart attacks at older ages.

While acknowledging the imperfections in the online calculator, officials from the AHA and ACC have stated they still feel it is representative of progress. They resolved to push forward with the guidelines, stressing that people should follow the recommendation to consult with their doctors about statin use.

To read the Times story on the risk calculator, click here.

To read the Times story on the guidelines, click here.

To download a copy of the guidelines report, click here.

To download the risk calculator, click here.