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We can (mostly) stop worrying about triglycerides

If our goal is to prevent cardiovascular events, then focusing on the cholesterol particles that clog the heart’s arteries is the more useful strategy.

This article was originally posted in the Montreal Gazette.

Medicine has clearly become much more complicated than it once was. Even in healthy patients with no active issues, the sheer number of things you need to check and monitor seems to be growing with time. Which is why jettisoning the detritus of unnecessary tests is so important. Not only does it save money, it also saves time and reduces the information overload that can overwhelm both doctors and patients when it comes to reviewing someone’s medical history.

So here’s my resolution for the new year. I’m going to (mostly) stop worrying about triglycerides.

Triglycerides, a component of cholesterol, are often measured on routine blood tests. It may surprise people to learn that cholesterol is not one thing, but is made up of many different molecules that have many different roles. Though we often talk about “good” HDL and “bad” LDL cholesterol, there are many different varieties, only some of which show up on a routine blood panel.

The reason triglycerides get routinely measured is two-fold. First, triglyceride levels are needed to accurately calculate someone’s LDL cholesterol. While LDL can be measured directly, it is most often calculated using a mathematical formula that requires you to input someone’s total cholesterol, HDL, and triglyceride level. But, elevated triglycerides were also routinely measured because of the belief that lowering them prevented heart disease.

The belief had some basis. Early studies like the Helsinki Heart Study showed that triglyceride-lowering medications like gemfibrozil did in fact reduce the risk of heart disease. But the future was not kind to this class of medications and the development of statins and other newer medications has rendered them largely obsolete. In the post-statin era, studies like FIELD and ACCORD showed that medications like fenofibrate might lower triglycerides but offered little cardiovascular benefit. And now, the PROMINENT study which was recently presented at the American Heart Association, seems likely to put the final nail in the coffin. A new medication called pemfibrate was tested against a placebo in patients with high triglycerides but otherwise low cholesterol. While the mediation lowered triglycerides by more than 25 per cent, it did not prevent cardiovascular events.

Before statins were available, these medications probably did have some role in cardiovascular-risk prevention because they do help to lower LDL, the bad cholesterol, by a modest amount. However, statins are so much more potent that they have largely eclipsed most older medications. Pemfibrate and its predecessor have largely failed because while they lower triglycerides they don’t seem to affect the things that really matter. It is becoming increasingly obvious that lowering bad cholesterol is how you reduce cardiovascular disease and that triglycerides on their own don’t seem all that relevant.

The implications in this shift of thinking are manifold. First, in an era where taking multiple medications is becoming an increasing burden for many people, simplifying someone’s prescription profile has clear benefits. Second, many people were told for years that they needed to be fasting in order to accurately measure their cholesterol levels. This was done because triglycerides can fluctuate significantly based on when and what you last ate. But now we can assess cholesterol levels and particle numbers using blood tests like apoB that are unaffected by your last meal.

There is one reason why treating high triglycerides may be important. Very high triglyceride levels can lead to pancreatitis and there is some rationale for treating them in that context. But otherwise the evidence for treating hypertriglyceridemia is thin, at best. If our goal is to prevent cardiovascular events, then focusing on the cholesterol particles that are atherogenic and clog the heart’s arteries is the more useful strategy. Which means that for 2023, we can have one less thing to worry about.


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