Dear Dr. Roach:
Recently, a cardiologist suggested I consider statins due to my “borderline” cholesterol levels. This led me to research statin therapy. I found that while statins may reduce the risk of cardiovascular events by nearly 50%, the actual impact seems quite small.
I shared this info with my cardiologist and opted against statin therapy, which he supported. I think it would be really helpful for your readers to understand this distinction better.
— T.G.
Dear T.G.:
The absolute risk reduction from a statin for someone without known heart disease largely hinges on that person’s overall risk factors, like age, sex, blood pressure, cholesterol, smoking habits, family history, and more. When heart disease is already present, the advantages of statins are significant enough that such detailed analysis often isn’t necessary.
Typically, the relative risk reduction from a statin is around 20%, though some may suggest a lower figure; achieving a 50% relative reduction isn’t currently feasible with existing medications.
I generally follow this methodical assessment with each patient considering statins, starting with an evaluation of their absolute risk. There are various calculators available for this; I often turn to tinyurl.com/PREVENTCalc and make modifications based on any relevant risk factors not included in the tool. Some patients prefer just to hear my opinion on the matter rather than delve into numbers, which is perfectly fine, but I like to collaborate closely with them.
For instance, take a 75-year-old man with a cholesterol level of 220 mg/dL, HDL at 45 mg/dL, and blood pressure reading 140/80 mmHg — which could all be viewed as “borderline.” Using the calculator, his estimated absolute risk stands at 19.4%. This represents how likely he is to develop some form of obstructive heart disease over the next decade, including risks of heart attack or mortality.
If he were to take a statin, we could reasonably estimate a 20% reduction in this absolute risk, leading to a new level of 15.5%. So, while the relative risk drops by 20%, the absolute reduction here would be 3.9%.
In contrast, consider a 50-year-old woman with the same risk profiles. Her absolute risk would be much lower at 3.6%. She’d still experience the 20% reduction, but this only translates to a 0.72% decrease, resulting in a new absolute risk of 2.88%.
Healthcare professionals often refer to a measure called the “number needed to treat” (NNT), which is influenced by the absolute risk reduction. In our earlier examples, approximately 26 75-year-old men would need treatment for ten years to prevent a heart attack or death, while around 139 50-year-old women would require treatment to see similar preventative benefits.
The advantage of statins—or any treatment aimed at decreasing heart disease risk—is contingent on a person’s initial risk level. Whether this makes sense for someone depends not only on the absolute reduction in risk but also on their feelings toward medication and concerns about heart disease.
In terms of cost, statins are generally quite affordable at around $5 to $10 a month. Serious side effects are rare; however, if they do occur, there are other alternatives available.
Readers can send questions to ToYourGoodHealth@med.cornell.
