The True Benefits vs. Side Effects of Statins

The True Benefits vs. Side Effects of Statins
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A Mayo Clinic visualization tool can help you decide if cholesterol-lowering statin drugs are right for you.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“Physicians have a duty to inform their patients about the risks and benefits of [whatever they prescribe]. However, physicians rarely communicate [the absolute risk numbers], such as numbers needed to treat”—in other words, how many people are actually helped by the drug; “numbers needed to harm”—in other words. how many people are actually hurt by the drug; “or prolongation of life”—how much longer will it enable to you to live—“despite patients wanting all this information.”

If doctors inform patients only about the relative risk reduction, for example telling patients a pill with cut their risk of heart attacks by 34 percent, 9 out of 10 agree to take it. Give them the same information framed as absolute risk reduction, though, “1.4 percent fewer patients had heart attacks,” and those agreeing to take the drug drops to only 4 out of 10. And use the number needed to treat, and only 3 in 10 patients would agree to take it. So, if you’re a doctor, and you really want the patient to take the drug, which statistic are you going to use?

The use of relative risk stats to inflate the benefits and absolute risk stats to downplay any side effects has been referred to as “statistical deception.” To see how one might spin a study to accomplish this, let’s look at an example. Here’s the incidence of heart attack over five years in those randomized to a placebo, compared to those getting the drug—a significantly lower risk. If you wanted statins to sound good, you’d use the relative risk reduction: 24 percent lower risk. If you wanted statins to sound bad, you’d use the absolute risk reduction, and just say 3 percent fewer heart attacks.

Then you could flip it around for the side effects. For example, they found that 0.3 percent, 1 out of the 290 women in the placebo group, got breast cancer over those five years, compared to 4.1 percent, 12 out of 286, in the statin group. So, a pro-statin spin on this study would be like a 24 percent drop in heart attack risk, and only 3.8 percent more breast cancers, whereas an anti-statin spin could be like only 3 percent fewer heart attacks compared to a 1,267 percent higher risk of breast cancer. Both portrayals are technically true, but you can see how easily you could manipulate people if you picked and chose how you were presenting the risks and benefits. So ideally, you’d use both: the relative risk reduction and absolute risk reduction stats.

In terms of benefits, when you compile a bunch of statin trials together, it looks like the relative risk reduction is 25 percent. So, if your 10-year risk of a heart attack or stroke is 5 percent, then taking a statin could take that down from 5 percent to 3.75 percent, for an absolute risk reduction of 1.25 percent, or a number needed to treat of 80, meaning there’s like a 1 in 80 chance that you’d avoid a heart attack or stroke taking the drug over the next 10 years. As you can see, as your baseline risk gets higher and higher, even though you have that same 25 percent risk reduction, your absolute risk reduction gets bigger and bigger. And by 20 percent baseline risk, you have a 1 in 20 chance of avoiding a heart attack or stroke over the subsequent decade if you take the drug.

So those are the benefits. In terms of risk, that breast cancer finding appeared to be a fluke. Put all the studies together, and there was no association between use of statins and risk of cancer. In terms of muscle problems, estimates range from just 1 in 1,000 to closer to 1 in 50.

If all those numbers are just blurring together, the Mayo Clinic developed a great visualization tool. For those at average risk, considering a statin over the next 10 years, of 100 people doing nothing, 10 may have a heart attack. If all 100 took a statin every day for those 10 years though, eight would still have a heart attack, but two will have been spared, so there’s like a 1 in 50 chance taking the drug would help you avert a heart attack over the next decade.

What are the downsides? The cost and inconvenience of taking a pill every day, which can cause some gastrointestinal side effects, muscle aching and stiffness in maybe 5 percent, reversible liver inflammation in 2 percent, and more serious damage in perhaps 1 in 20,000 patients.

Now note these two happy faces represent heart attacks averted, not lives saved. The chance a few years of statins will actually save your life if you have no known heart disease is about 1 in 250.

If you want a more personalized approach, the Mayo Clinic has an interactive tool that also lets you calculate your 10-year risk. You can get there directly by going to bit.ly/statindecision.

Please consider volunteering to help out on the site.

Video production by Glass Entertainment

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“Physicians have a duty to inform their patients about the risks and benefits of [whatever they prescribe]. However, physicians rarely communicate [the absolute risk numbers], such as numbers needed to treat”—in other words, how many people are actually helped by the drug; “numbers needed to harm”—in other words. how many people are actually hurt by the drug; “or prolongation of life”—how much longer will it enable to you to live—“despite patients wanting all this information.”

If doctors inform patients only about the relative risk reduction, for example telling patients a pill with cut their risk of heart attacks by 34 percent, 9 out of 10 agree to take it. Give them the same information framed as absolute risk reduction, though, “1.4 percent fewer patients had heart attacks,” and those agreeing to take the drug drops to only 4 out of 10. And use the number needed to treat, and only 3 in 10 patients would agree to take it. So, if you’re a doctor, and you really want the patient to take the drug, which statistic are you going to use?

The use of relative risk stats to inflate the benefits and absolute risk stats to downplay any side effects has been referred to as “statistical deception.” To see how one might spin a study to accomplish this, let’s look at an example. Here’s the incidence of heart attack over five years in those randomized to a placebo, compared to those getting the drug—a significantly lower risk. If you wanted statins to sound good, you’d use the relative risk reduction: 24 percent lower risk. If you wanted statins to sound bad, you’d use the absolute risk reduction, and just say 3 percent fewer heart attacks.

Then you could flip it around for the side effects. For example, they found that 0.3 percent, 1 out of the 290 women in the placebo group, got breast cancer over those five years, compared to 4.1 percent, 12 out of 286, in the statin group. So, a pro-statin spin on this study would be like a 24 percent drop in heart attack risk, and only 3.8 percent more breast cancers, whereas an anti-statin spin could be like only 3 percent fewer heart attacks compared to a 1,267 percent higher risk of breast cancer. Both portrayals are technically true, but you can see how easily you could manipulate people if you picked and chose how you were presenting the risks and benefits. So ideally, you’d use both: the relative risk reduction and absolute risk reduction stats.

In terms of benefits, when you compile a bunch of statin trials together, it looks like the relative risk reduction is 25 percent. So, if your 10-year risk of a heart attack or stroke is 5 percent, then taking a statin could take that down from 5 percent to 3.75 percent, for an absolute risk reduction of 1.25 percent, or a number needed to treat of 80, meaning there’s like a 1 in 80 chance that you’d avoid a heart attack or stroke taking the drug over the next 10 years. As you can see, as your baseline risk gets higher and higher, even though you have that same 25 percent risk reduction, your absolute risk reduction gets bigger and bigger. And by 20 percent baseline risk, you have a 1 in 20 chance of avoiding a heart attack or stroke over the subsequent decade if you take the drug.

So those are the benefits. In terms of risk, that breast cancer finding appeared to be a fluke. Put all the studies together, and there was no association between use of statins and risk of cancer. In terms of muscle problems, estimates range from just 1 in 1,000 to closer to 1 in 50.

If all those numbers are just blurring together, the Mayo Clinic developed a great visualization tool. For those at average risk, considering a statin over the next 10 years, of 100 people doing nothing, 10 may have a heart attack. If all 100 took a statin every day for those 10 years though, eight would still have a heart attack, but two will have been spared, so there’s like a 1 in 50 chance taking the drug would help you avert a heart attack over the next decade.

What are the downsides? The cost and inconvenience of taking a pill every day, which can cause some gastrointestinal side effects, muscle aching and stiffness in maybe 5 percent, reversible liver inflammation in 2 percent, and more serious damage in perhaps 1 in 20,000 patients.

Now note these two happy faces represent heart attacks averted, not lives saved. The chance a few years of statins will actually save your life if you have no known heart disease is about 1 in 250.

If you want a more personalized approach, the Mayo Clinic has an interactive tool that also lets you calculate your 10-year risk. You can get there directly by going to bit.ly/statindecision.

Please consider volunteering to help out on the site.

Video production by Glass Entertainment

Motion graphics by Avo Media

Doctor's Note

This is the third video in a four-part series on statins. Missed the first two installments? See Who Should Take Statins? and Are Doctors Misleading Patients About Statin Risks and Benefits?.

How Much Longer Do You Live on Statins? That’s coming up next and rounding out the series.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

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