I met a new patient recently who was quite concerned about his cholesterol after his last doctor suggested he go on a statin. After discussing this patient’s medical history and reviewing his labs, it became obvious that he does NOT have a cholesterol problem, and certainly not one that warrants medication. This is a common scenario I run into in clinical practice, so I thought it would be useful to take a few minutes to run through some of the thought processes that a doctor should take when evaluating a patient’s cholesterol.
Without further ado, let’s delve in. Here are a few key points that are important to understand when thinking about cholesterol. Read through them, and then I’ll come back to the patient.
Your Cholesterol is not the point. What I mean by this is simply that the only reason we care about cholesterol is because it can be a risk factor for developing a heart attack or stroke. There are no symptoms to having high cholesterol and no other known downside to it. If we had a crystal ball and could tell with 100% certainty that a particular patient would never suffer a heart attack no matter how long they live, we could confidently tell that person to ignore their cholesterol completely. And yet I routinely meet patients who are convincingly demonstrated to have very little risk for developing a coronary event (we’ll cover how in a moment) but are told nonetheless to take medicine to lower their cholesterol. This makes no sense. High cholesterol is not in and of itself a disease, it’s merely a risk factor (sometimes) for heart disease. Keeping this point clear in our minds is of the utmost importance.
Cholesterol is not even close to your most important risk factor for cardiac disease. I’m asked more often by patients “what is my cholesterol?” than about any other lab value. And yet, cholesterol isn’t even close to being the most important factor when it comes to developing heart disease. Your blood sugar, your metabolic health, your blood pressure, and whether or not you smoke are all vastly more predictive of your cardiac risk than your cholesterol is. If these factors are all in check, even if your cholesterol is quite high, you are probably at low risk for a cardiac event. By contrast, if you have one or more of these risk factors, even if your cholesterol numbers look “textbook” perfect, you are probably at an elevated risk.
Your total cholesterol doesn’t matter at all. I can’t stress this point enough. The idea that an elevated level of total cholesterol puts someone at risk for heart disease stems from the early days of cholesterol research, when the fact that there are different types of cholesterol in the bloodstream (e.g. LDL, HDL, etc) was not yet well known. Some of the early studies from the 1950s and 1960s did suggest that a high total cholesterol level was somewhat predictive of heart attacks and strokes, but numerous later studies in which the various subgroups of cholesterol were accounted for revealed that it was the levels of these different subgroups, not the total cholesterol, that mattered. We’ve known pretty convincingly for about fifty years now that there simply isn’t any clear relationship between your total cholesterol and your risk for cardiovascular disease. I ignore this number. Life insurance companies ignore this number. You should ignore this number.
HDL and Triglycerides are flip sides of the same coin. With vanishingly rare exceptions, as your HDL cholesterol goes up, your triglycerides go down, and vice versa. I’ll spare you the geeky science of why this is. But in a sense, this makes interpreting a cholesterol panel a bit simpler. You really can focus on two metrics: your LDL, and your HDL/Triglycerides.
Your HDL and Triglycerides are the most predictive numbers in your cholesterol panel. A standard cholesterol panel – the type you likely get every year at your routine checkup – gives four values: a total cholesterol (useless – see point three above); your LDL cholesterol (the so-called “bad” cholesterol); your HDL cholesterol (the so-called “good” cholesterol); and your triglycerides. All of these numbers are important, and as a general rule you want your HDL to be high, and your triglycerides and LDL to be low. That said, having high HDL and low triglycerides is a good marker for overall metabolic health, and this in turn is ultimately more predictive than LDL for cardiovascular disease. In other words, while it’s nice to have a low LDL, it’s better to have a high HDL and a low triglyceride level.
LDL responds to fat, HDL and triglyceride respond to carbs. This is where nutritional complexity starts to creep in. It’s true that reducing saturated fat in your diet reduces the level of LDL cholesterol. And taken in isolation, that’s probably a good thing. However, if you want to lower your triglycerides and raise your HDL, the best way to do that is to limit your intake of sugar and refined carbohydrates such as white bread, pasta, white rice, and sweet drinks. The “eat less fat” advice is therefore very bad advice for many people. Nutritional counseling really needs to be tailored to each individual patient. Many patients (not all!) will get more mileage from a higher fat/lower carb type of diet than they will by reducing their fat intake.
It’s helpful to calculate your risk for a cardiovascular event before doing anything else. Remember what I said in point one? The only reason we care about any of this is because poor cholesterol numbers might be a red flag that you are on your way to having a cardiovascular event. How can you tell if you are at risk for such an event? There are a few ways, but the quickest is to use the risk calculator created by the American Heart Association, which I link to here. Simply plug in your age, gender, blood pressure, cholesterol numbers, and a few other metrics such as whether or not you smoke, and it will estimate your risk for having a cardiovascular event in the next ten years. Is this perfect? Absolutely not. It’s simply using statistics to estimate your risk, and hence it’s no rock solid guarantee in either direction. But integrating this into your thought process is much more helpful than just looking at your cholesterol numbers in isolation, and gives you a great starting point for making further decisions about dietary changes, medication, additional testing, or any other “next steps.”
I’m going to stop here, in the interests of brevity. But there’s in fact way more to discuss about this topic. To really give a complete picture, we ought to discuss cholesterol particles, lipoprotein testing, and coronary artery calcium scanning – topics that I’ve briefly covered in a prior post, and which I’ll link to here – and which represent a more modern and accurate way to assess your risk for a cardiovascular event than anything you can glean from a cholesterol panel.
The fact remains however that, at most doctors offices, a standard cholesterol panel is as far as the testing goes. Too many patients – and stubbornly, still, too many doctors – have a very simplistic narrative of this lab result (high = bad, low = good), when in fact this is a very vast, complex, and nuanced topic that requires an individualized approach to each and every patient.
Which brings me back to the patient I mentioned at the start of my post. He saw his last primary care doctor for a routine physical and had the following numbers:
Total cholesterol: 260
HDL cholesterol: 81
Triglycerides: 74
LDL cholesterol: 164
His last doctor told him that his cholesterol was high, and therefore he should go on a statin. We took a different approach:
First off, I explained to him that total cholesterol doesn’t matter.
Next, eyeballing his numbers, I note that his LDL is a little high, which might be concerning, but that the more important HDL and triglyceride numbers were excellent, which implies a low overall risk.
Then I calculated his 10 year risk using the risk calculator: it was less than 2%. Meaning he has a better than 98% chance of NOT having a heart attack over the coming decade. Even the standard guidelines that are currently in place – which mind you were written with influence from the very pharmaceutical companies that make large profits selling cholesterol lowering medication – unequivocally state that a patient in such a low-risk category does NOT need to go on medication for their cholesterol.
For further evaluation, we then decided to test his lipoprotein numbers, and a CAC scan. The results were reassuring.
Based on all of this, we agreed that he doesn’t need medication now or anytime in the near future and that his best way to avoid a heart attack is to work on a healthy lifestyle and to have us repeat the above evaluation every few years to make sure we stay well ahead of any problems if they do develop.
