More than twenty million Americans take cholesterol-lowering drugs known as “statins”—drugs with brand names such as Lipitor, Zocor, Pravachol, and Crestor and generic names of atorvastatin, simvastatin, pravastatin, and rosuvastatin. These drugs account for over 20 billion in sales annually and often figure prominently in discussions between doctors and patients. Using statins has been shown to reduce the 10-year risk of a heart attack or stroke by 20-30 percent. Based in part on these results, some groups have recommended that LDL (the so-called “bad” cholesterol) be kept below 130 in healthy people and below 100 in people with a history of diabetes, heart attack, or stroke. Some have advocated more ambitious goals of getting LDL cholesterol below 70 in higher-risk patients. Doctors are often scored against these goals when companies try to quantify the quality of care they provide and their pay is increasingly being tied to meeting these goals.
Evidence that statin use carries a risk of causing or exacerbating diabetes has been building for the last ten years since a trial known as the JUPITER trial showed a small but significant increase in diabetes. A large meta-analysis (or combination of multiple studies) including over 91,000 patients was published late last year and evaluated the degree to which this effect was seen in other studies. This analysis found that about 1 new case of diabetes was seen for every 255 patients treated with statins. For the more aggressive regimens with lower LDL goals, the number increased to 1 new case in every 125 patients. Based in part on this study, in late February 2012 the FDA has required that stain drugs carry a warning of the increased risk of diabetes.
Despite the overall positive data on the ability of statins to prevent heart disease or stroke, the benefits of stains are not the same for all people. For example, the risk of having a second heart attack in ten years after a first one is relatively high—roughly 30% or more depending on other risk factors. On the other hand, the risk of a heart attack in a forty year old male with no history of heart disease and few risk factors is 1%. In contrast, a fifty year old male smoker with no history of heart disease, a systolic blood pressure of 144mmHg, a total cholesterol of 250, and a HDL of 30 has a 28% risk of developing a heart attack in the next ten years. Although each of these people may experience a 20-30% risk reduction with statin therapy, the absolute benefit is going to be much higher in the 50 year old, going from 28% to 19% risk than the young person who may go from 1% to 0.7% risk.
The bottom line is that although statins have a well-deserved popularity because they can reduce the chance of dying from a heart attack or stroke, no drug is free from side effects and the choice of whether or not to use a statin should be personalized based on individual risk. On one hand these drugs are popular for a reason and the risk is indeed small. People who have already had a heart attack or stroke should not use this as a reason to stop statins as the benefit for them still outweighs the risk. On the other hand, people who have never had a heart attack or stroke may want to determine their baseline cardiac. There are free online calculators readily available from at the NIH (http://hp2010.nhlbihin.net/ATPiii/calculator.asp?user) or by googling “Framingham calculator” based on a large heart disease study. Knowledge of this risk can be used to start a discussion with your doctor. Although many patients may take this as a reason to avoid statins for fear of diabetes, the truth is that people put themselves at risk more from their choices about exercise and diet than from their choices about using statins. Many of the lifestyle choices that lead to high cholesterol are the same choices that lay the groundwork for diabetes. Many more people who take statins will develop diabetes as a result of these choices rather than the choice of statins. If the publicity of statins and diabetes lead people to reassess the choices they make on how they eat and live, they will have served a good purpose.