Checking The Math in New Statin Guidelines
Today’s piece is an interlude in the Cholesterol Mistake series (parts 1 [https://researchtranslation.substack.com/p/the-first-cholesterol-mistake], 2 [https://researchtranslation.substack.com/p/cardiologys-nonfatal-fatal-mistake], 3 [https://researchtranslation.substack.com/p/cholesterol-the-big-mistake], and 4 [https://researchtranslation.substack.com/p/cholesterol-what-went-wrong]) which was inspired by the new AHA lipid guidelines. I got sidetracked by the figure below from those guidelines, and ended up in the weeds—deep enough to go much longer than normal. Apologies for length, hope the payoff is worthy. Next week part 5, back to brevity!
“He says the chest pain started suddenly an hour ago, it feels ‘tearing’, and radiates to his back, shoulders, and arms.”
Jeff, my senior resident, raised an eyebrow as he presented the case of a 48 year-old man. “He’s in a lot of pain, too. I ordered dilaudid—he says that’s worked for him in the past—and I put him first in line for CT.”
Jeff ended with a question, “So, maybe I’ll call surgery?”
I nodded. “Let me talk to him first” I said, walking toward room 3.
“Ok,” Jeff hesitated. “I feel like we should hustle, you know? I think he’s dissecting.”
A tear in the wall of the body’s main artery—aortic dissection—can be rapidly fatal.
“I get it. Give me two minutes.”
Turning the corner, I glimpsed the man in room 3. He was well dressed and appeared comfortable. In the room I examined him carefully and listened intently to his story. It was a good story for aortic dissection.
Too good.
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Parts of the new AHA Lipid Guideline remind me of the man’s act. One was highlighted [https://www.sensible-med.com/p/guidelines-evidence-based-medicine] recently by the wonderful Adam Cifu of Sensible Medicine [https://www.sensible-med.com/] (which I read religiously for honest, often fearless commentary from the front lines).
Last week Cifu wrote [https://www.sensible-med.com/p/guidelines-evidence-based-medicine] about Figure 4 in the new AHA guideline. He lamented how poorly such graphs translate in the exam room because humans have preferences, and quirks, and rarely if ever fit the average numbers envisioned by guidelines.
What he did not discuss—and we will—is the veracity of the math in those graphs.
This is not a small matter. Figure 4 is titled, “The Logic For Defining…” 3% or more as the 10-year risk threshold for starting statins. Indeed it is the only place in the 123-page document where they show us how they arrived at this number.
Again, this is not academic. The 3% threshold recommends statins for an additional 25 million U.S. adults. They deserve to know why.
So let’s find out.
Both graphs plot cardiac risk versus benefit. The x-axis (bottom line of the graphs) shows a person’s 10-year heart risk, which anyone can get from the AHA’s online calculator [https://professional.heart.org/en/guidelines-and-statements/prevent-calculator].
The y-axis (vertical) shows possible benefits of statins expressed as Numbers Needed to Treat, or NNT. For those new to the concept, NNTs get smaller as benefits get bigger because fewer people ‘need to be treated’ for one of them to experience a benefit. This is nicely illustrated by the graph’s red curve which shows NNT dropping (i.e. benefits getting bigger) as the risk of heart problems rises. That’s because the bigger the chance of a benefit the lower the NNT; and the higher a patient’s risk the more likely they’ll benefit.
The dotted vertical line in Panel A represents someone with a 3% risk of a heart problem—the new threshold. Wording above the graph tells us that statins reduce risk by 35%, or about a third. When a 3% risk drops by about a third, it’s dropping by 1%. That means exactly 100 people ‘need to be treated’ for 1 to benefit, which is why the dotted line and the NNT curve converge at 100.
Crucially, they tell us an ‘NND’, which is the same as NNT but refers to statin-induced diabetes. Their “NND=100” means they assume exactly 1% of people will get diabetes from 10 years of statins—the same as the chance of benefit at 3% coronary risk.
What’s it all mean? They are saying (obtusely and indirectly) that a 1% diabetes rate and a 1% coronary benefit is a break-even point and it happens at a 3% risk of heart problems. Anyone with less risk will see less benefit, and thus statins will more likely harm than help. Anyone at higher risk sees more benefit and is more likely helped than harmed.
Get it?
And again, to be explicit: This is the only place in their guideline where they explain the new 3% threshold. Which suggests to me that the committee likely saw this graph and agreed it should drive the new recommendations.
All of which makes the assumption of 1% for the diabetes number a little weird. The guideline’s most cited source on diabetes is an 2024 analysis [https://www.thelancet.com/journals/landia/article/PIIS2213-8587(24)00040-8/fulltext] that found statins cause diabetes at 0.12% per year. For 10 years that’s 1.2% (not 1%), which means harms are greater than benefits at the new threshold.
But you know what? Whatev. Let us not quibble. Perhaps they estimated downward to 0.1% per year, and although it shifts the graph (their threshold should be 4%) who cares?! It’s only 8 million more people mistakenly recommended for statins.
It’s cool, it’s cool. We won’t panic.
Until Panel B.
Panel B is the same calculation, only for high-dose statins. Here the AHA says 3% get diabetes from the drugs after ten years. The break-even point is a 7% risk, because they say high-dose statins reduce risk by 45%, turning 7 into 4—a 3% drop, matching the increase in diabetes.
Get it?
But this time their diabetes estimate departs from the data by a lot. The guideline’s preferred source [https://www.thelancet.com/journals/landia/article/PIIS2213-8587(24)00040-8/fulltext] found that high-dose statins cause diabetes in 1.27% per year, or 12.7% after ten years.
Where did they get 3%, pray tell? It may come from their last guideline [https://www.ahajournals.org/doi/10.1161/01.cir.0000437738.63853.7a] 13 years ago, which used the 3% number but cited a single 2010 study as their evidence source. That would be strange because the updated 2024 analysis includes data from 23 trials and is plainly the new guideline’s go-to source, cited and quoted throughout the document.
So why didn’t they use it? Shrug. Inexplicable.
In any case, using their logic—that diabetes is the one harm worth calculating, and the benefit of high-dose statins is a 45% risk reduction—the correct break-even point would not be at 7% coronary risk, but 28%.
Which is interesting because very few without heart disease have a risk that high. Levels above 20% are seen overwhelmingly in secondary prevention. Based on this corrected calculation, therefore, the AHA should be cautioning against high-dose statins in primary prevention.
Again, that is using their numbers and logic, but correcting the outdated input for statin-induced diabetes.
But of course, it is not just that they forgot to update their diabetes numbers. There are lots of other flaws in the AHA logic. For instance, that diabetes is the only downside. As Adam Cifu points out, “There is the cost of the medication, the monitoring, the visits, and the turning an enormous swath of the population into patients.”
Not to mention muscle pain and damage in at least 5% [https://www.ahajournals.org/doi/full/10.1161/CIRCULATIONAHA.112.136101], or 1 in 20 (which is certain to be an under-count).
And then there’s the prickly issue of ‘benefits’.
Last week in part 4 [https://researchtranslation.substack.com/p/cholesterol-the-big-mistake] we walked through the raw numbers to better define statin benefits. Briefly, in the AHA graphs above the benefit consists of three parts: roughly 45% nonfatal MI, 25% nonfatal stroke, and 30% death.
But as we discussed there is no proven reduction in death at risk levels <20%. The 2012 paper—the AHA’s source—shows clearly that in this risk group mortality was unaffected (see the figures and tables in part 4 [https://researchtranslation.substack.com/p/cholesterol-the-big-mistake]).
And yet the guideline is quietly counting deaths as a benefit. That is, to put it mildly, inconsistent with the evidence. If we therefore remove this portion of the benefit and recalibrate, the AHA’s treatment threshold shifts from 3% to 5%.
Then we make the big move.
Now we remove what patients don’t take statins for: to prevent ‘nonfatal MI’. As discussed in part 2 [https://researchtranslation.substack.com/p/cardiologys-nonfatal-fatal-mistake], this endpoint is a historical mistake, and in modern trials often represents little more than a lab abnormality. This explains why it is proven [https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2785560] not to be associated with death or disability, the two outcomes people actually take statins to prevent.
When we remove nonfatal MI, leaving nonfatal stroke as the one proven, patient-centered benefit, the new break-even point occurs at a 14% baseline coronary risk.
Below is a table showing mathematically correct break-even points using the AHA’s logic (diabetes is the one harm; statins reduce risk 35% and 45%), both with and without their outdated inputs.
The table suggests that, by their own framework, the AHA should recommend only moderate-dose statins, and only for those at >14% risk. High-dose statins, meanwhile, are more likely to harm than help virtually everyone in primary prevention.
But it gets worse.
Presumably, the AHA agrees that patients should also be informed about common, established harms like muscle pain and damage. If those are incorporated into the same break-even framework, the picture changes again:
Essentially, no one in primary prevention would be eligible—and few in secondary prevention.
At this point, however, the model itself should be questioned. The AHA’s framework assumes that all harms and benefits carry equal weight—that a 1% reduction in coronary risk perfectly offsets a 1% increase in diabetes, or a 1% increase in muscle injury. That is not how people feel outcomes.
Rather than impose those values, we can simply show people the numbers and let them decide. For someone at a 14% baseline risk considering moderate-dose statins, the likely effects look like this:
* Mortality: None
* Avoiding a nonfatal stroke: 1 in 83
* Getting diabetes from the drug: 1 in 83
* Muscle pain and damage: 1 in 20
This—finally—is the conversation we should be having. People decide what matters most using their values. Not the AHA’s, or their doctor’s, or mine. But theirs.
When I examined my possible dissection patient I found no signs of illness—the third red flag. The first was a request for opiates, the second was an unlikely story.
Skeptical, I dug one layer deeper, offering him non-opiate pain control and a full work-up for possible aortic dissection. But alas, the lack of opiates was a deal breaker for the man and he walked out. While flipping me the bird.
The AHA guideline is, in my opinion, littered with red flags.
One is a blind faith in the Lipid Hypothesis. Another is an unlikely story—that low risk healthy people should take cholesterol drugs for the rest of their lives. And one more is a graph with data inputs that don’t match their own citations.
All of which should make us dig deeper. And Figure 4 is where ‘X’ marks the spot.
What is most striking about the graphs, to me, is that they’re offered as the scientific justification for a major expansion in treatment—and yet the underlying assumptions are opaque and untraceable.
Why wouldn’t they show us their work?
The answer, it seems, is that their model uses numbers that can’t be reconciled with the underlying data, obscures key calculations, and relies on outcomes that people taking statins don’t care about.
This is not how science fails. It is how it drifts—quietly, incrementally, until the appearance of rigor replaces the thing itself. The guideline sounds good, looks good, and has fancy, science-y graphs that blind and confuse.
Figure 4 is, in this sense, the centerpiece of the illusion—a masterstroke of form over function, style over substance, and spectacle over science.
Which is why their conclusions look convincing, even when they are not.
And why people considering statins might want to dig a layer deeper.
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