Non-HDL Cholesterol and The New Cholesterol Guidelines

If non-HDL cholesterol was viewed as a key predictor of cardiac disease risk (on par with apoB or LDL particle testing), why was it abandoned in the new November 2013 cholesterol guidelines?

This is something I’ve been thinking about for a while.  Because for those with diabetes or high triglycerides, it was considered vital to know non-HDL cholesterol. (Do You Know Your Non-HDL Cholesterol? explains why, and how easy it is to calculate from just a standard cholesterol lipid blood test.)

Let me start with a brief, very non-technical definition (for more technical info click blog post link above).  Non-HDL cholesterol is a measure that estimates the level of ALL the bad types of cholesterol in the blood.  Think of it this way: subtracting HDL (good) from total cholesterol yield the non-HDL cholesterol number, which is a measure of all the ‘bad’ cholesterol in the blood. That means it’s a measure of all LDL: the ‘regular-old’ LDL (bad) cholesterol number, which is the number that appears on a report, plus all the other carriers of ‘bad’ cholesterol, such as VLDL (very low density lipoprotein) and IDL (intermediate density lipoprotein) – which are not included in the regular-old LDL cholesterol measurement listed on a cholesterol lipid panel report.

Though it was not as widely known/used by doctors as regular-old LDL cholesterol, it’s true that non-HDL-C was  proven to be a better indicator of cardiac disease risk than just LDL cholesterol.

Indeed, as explained in the Mayo Clinic’s Cardiovascular Risk Assessment Beyond LDL Cholesterol: Non-HDL Cholesterol, LDL Particle Number, and Apolipoprotein B, non-HDL-C  is a better measure of cardiac risk than LDL cholesterol:

“Several known limitations make LDL-C a less accurate marker of cardiovascular risk than either non-high-density lipoprotein cholesterol (non-HDL-C), LDL particle number, or apolipoprotein B (apoB).”

“Advocacy for non-HDL-C began following widespread recognition of its superiority over LDL-C as a measurement of vascular event risk and demonstrated equivalency to apoB or LDL particle number in some clinical trials.”

If it was widely accepted in the medical community that non-HDL-C was a better predictor than LDL alone – and indeed, a good proxy for apoB or LDL particle testing, why were BOTH the LDL and the non-HDL-C measures abandoned in the new guidelines?

The answer seems to be that there is no rationale for setting a specific number target for either LDL or non-HDL-C.

I get it for LDL cholesterol. LDL was used as a key measure to determine whether someone should take a statin, even though there was no real rationale for a specific LDL number as a goal (which is crazy but is basically what’s been the case for many years now). Thus, the committee recommended a new risk assessment measure that was based on research – and eliminated the ‘random’ LDL goal.

Makes sense.

And yet.

If it is/was widely accepted and studies have shown that apoB and LDL particle size are predictive of cardiac risk, and non-HDL-C is an easy, cost-effective way to approximately measure apoB and LDL particle size (because non-HDL is calculated from a typical cholesterol test – not a whole new test like apoB) then it seems to me that knowing your Non-HDL-C is a good idea.

But hey, I’m no doctor. (And I don’t even pretend to play one on TV). So I could be wrong.

That said, I’m concerned. The new guidelines say I’m (suddenly, now) very low risk for cardiac disease. But my non-HDL cholesterol is significantly higher than the old “goal” of 130 for those with high triglycerides.

And I get that the 130 figure is not, in and of itself, a meaningful target.

I do.  Truly.

But it seems clear since my non-HDL-C is “high” compared with ‘normal’ or a lot of other people, that this might indicate a potential problem. And thus warrant action.  Not treatment – I get that it doesn’t make sense to recommend a statin based on a goal number that’s not grounded in research.

But to me, it seems that if non-HDL-C is greater than 130 then further testing could be indicated.

Again, I’m no doctor.

But I think it’s important to ASK about this.  Perhaps the fact that my non-HDL is high indicates the need apoB and/or particle size testing – or one or several of the tests the AHA now indicates for those who might be at risk: see New Cholesterol Guidelines – An App For That.

Good thing I’m due for my annual checkup soon.  I will ask my doctor about these tests. AGAIN.