Lies, damned lies, and statistics

In the last Heart Scan Blog post, I discussed the question of whether statin drugs provide incremental benefit when excellent lipid values are already achieved without drugs.

But I admit that I was guilty of oversimplification.

One peculiar phenomenon is that, when plaque-causing small LDL particles are reduced or eliminated and leave relatively benign large LDL particles in their place, conventional calculated LDL overestimates true LDL.

In other words, eliminate wheat from your diet, lose 25 lbs. Small LDL is reduced as a result, leaving large LDL. Now the LDL cholesterol from your doctor's office overestimates the true value.

Anne raised this issue in her comment on the discussion:

I eliminated wheat - and all grains - from my diet nearly three years ago (I eat low carb Paleo). My fish oils give me a total of 1680 mg EPA and DHA per day, and my vitamin D levels since last year have varied between 50 ng/ml and 80 ng/ml. However, my lipid profile is not like either John's or Sam's:

LDL cholesterol 154 mg/dl
HDL cholesterol 93 mg/dl
Triglycerides 36 mg/dl
Total cholesterol 255 mg/dl

My cardiologist and endocrinologist are happy with my profile because they say the ratios are good, no one is asking me to take a statin. My calcium score is 0.



However, if we were to measure LDL, not just calculate it from the miserably inaccurate Friedewald equation, we would likely discover that her true LDL is far lower, certainly <100 mg/dl. (My preferred method is the bull's eye accurate NMR LDL particle number; alternatives include apoprotein B, the main apoprotein on LDL.)

So Anne, don't despair. You are yet another victim of the misleading inaccuracy of standard LDL cholesterol determination, a number that I believe should no longer be used at all, but eliminated. Unfortunately, it would further confuse your poor primary care doctor or cardiologist, who--still believe in the sanctity of LDL cholesterol.

By the way, the so-called "ratios" (i.e., total cholesterol to HDL and the like) are absurd notions of risk. Take weak statistical predictors, manipulate them, and try to squeeze better predictive value out of them. This is no better than suggesting that, since you've installed new brakes on your car, you no longer are at risk for a car accident. It may reduce risk, but there are too many other variables that have nothing to do with your new brakes. Likewise cholesterol ratios.

Comments (8) -

  • Jeff

    4/18/2009 12:02:00 PM |

    I am in a similar boat.  I eliminated wheat, added cod liver oil(1-1.5 TBS or so per day), and take vitamin D supplements(gel caps around 4-5K IU per day).  Here were my results:

    TOTAL: 272
    HDL: 76
    LDL(calculated): 184
    Triglycerides: 62

    I strongly suspect the LDL is BS due to large particle size.  I will only be able to tell with the NMR, which I will do sometime this year.  I am not worried so I am in no rush.

  • arnoud

    4/18/2009 1:26:00 PM |

    Dr. Davis, thank you for providing such eye-opening insights in the interpretation of lipid testing results, and for explaining the limits of the usefulness of these measurements.

    However, in the typical doctor's office, the high (calculated) LDL prompts the doctor to push for treatment (including statins).  My doctor tells me that I need not avoid statins, as he is taking those himself, and he wouldn't if he'd think they were a problem.

    I can take my NMR Liposcience LDL particle count result to my doctor, and tell him that my real LDL number is 1/10th of the LDL particle count.  This actual number looks great!  How can I show my doctor that this calculation is correct (LDL particle count divided by 10), and that the standard Framingham calculated LDL should be ignored.   Is there a reference paper I can show my doctor, which explains the science behind the "LDL particle count divided by 10" rule?

  • john elfrank

    4/18/2009 1:35:00 PM |

    I had a coronary calcium scan a  few years ago. My score was about 350 with most of the calcium in the LAD.

    My Manhattan cardiologist responded by putting me on the treadmill and doing an eco stress test. I passed it with flying colors.


    I went to my internist who said  I should be concerned about that calcium score. I said my cardio won't give me any other tests. He said to go back and tell him I have chest pains. I did, got the angiogram and a stent for the 80% blockage in my "widow-maker" LAD.

    Now my lipid profile (I have dyslipidemia) is LDL 23, HDL 23, triglycerides 350 (1000 w/o meds). I had thyroidectomy in 1991 and take synthroid 200 mg.

    My combo thereapy is:
    2000 Niaspan, 40 Simvastatin, 200 Co-enzyme Q10, 1200 fish oil. It'a about as aggressive as my body can stand. Tricor and other fibrates interfere with synthroid absorption (I bet you didn't know that).

    My questions are:
    1. Would it be better for me to take the new combo Simvastatin/Niaspan drug rather than take them separately?

    2. Just passed a nuclear stress test. Should I insist on another angiogram soon?

    3. Would another calcium scan be useful?

    Thanks,

    John

  • sk

    4/18/2009 3:38:00 PM |

    this is absolutely spot on!  My numbers prior to NMR showed a total cholesterol of 150, HDL of 41, and TRG of 53.  Because of family history, my internist had me take NMR study and results showed that my particle number for LDL was 1795 and all small particles.  Since eliminating wheat and being on a statin my particle number is down to 1305,but still all small. Not sure that size can be changed, probably genetic.  
    Sadly, many out there think they have a fine profile from indirect measurement, and reality is that many probably do not.

  • Kiwi

    4/18/2009 10:05:00 PM |

    What is the recommended range for the ApoB test?
    My lab gives this:

    Male reference range 0.52 - 1.09 g/L
    Female reference range 0.49 - 1.03 g/L

    Using the Immunoturbidimetric method.
    VAP and NMR tests not available here.

    http://www.labnet.co.nz/testmanager/index.php?fuseaction=main.DisplayTest&testid=292

  • Dr. B G

    4/20/2009 9:42:00 PM |

    Anne,

    Those are FANTASTIC, phenomenal labs !!!

    You go GIRL!

    -G

  • Dr. B G

    4/20/2009 9:42:00 PM |

    Anne,

    Those are FANTASTIC, phenomenal labs !!!

    You go GIRL!

    -G

  • Ravi

    4/23/2009 9:42:00 AM |

    I strongly suspect the LDL is BS due to large particle size. I will only be able to tell with the NMR, which I will do sometime this year. I am not worried so I am in no rush.

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The myth of mild coronary disease

The myth of mild coronary disease

I hear this comment from patients all the time:

"They told me that I had only mild blockages and so I had nothing to worry about."

That's one big lie.

I guess I shouldn't call it a lie. Is it a lie when it comes from ignorance, arrogance, laziness, or greed?

"Mild coronary disease" is usually a label applied to coronary atherosclerotic plaque that is insufficient to block flow. Thus, having a few 20%, 30%, or 40% blockages would be labeled "mild." No stents are (usually) implanted, no bypass surgery performed, and symptoms should not be attributable to the blockages. Thus, "mild."

The problem is that "mild" blockages are no less likely to rupture, the eruptive process that resembles a little volcano spewing lava. Except it's not lava, but the internal contents of atherosclerotic plaque. When these internal contents of plaque gain contact with blood, the coagulation process is set in motion and the artery both clots and constricts. Chest pains and heart attack result.

So, the essential point is not necessarily the amount of blood flow through the artery, but the presence of coronary atherosclerotic plaque. Just having plaque--any amount of plaque--sets the stage to permit plaque rupture.

One thing is clear: The more plaque you have, the greater the risk for rupture. But the quantity of plaque cannot be measured by the "percent blockage." It is measured by the lengthwise extent of plaque, as well as the depth of plaque within the wall. Neither of these risk features for plaque rupture can be gauged by percent blockage.


Coronary atherosclerosis is a diffuse process that involves much of the length of the artery. It is therefore folly to believe that a 15 mm long stent has addressed the disease. This is no more a solution than to replace the faucet in your kitchen in a house with rotting pipes from the basement up.

The message: ANY amount of coronary plaque is reason to engage in a program of prevention--prevention of plaque rupture, prevention of further plaque growth, perhaps even regression (reversal). It is NOT a reason to be complacent and buy into the myth of "mild" coronary disease, the misguided notion that arises from ill-conceived procedural heart disease solutions.


Image courtesy Wikipedia.

Copyright 2008 William Davis, MD

Comments (27) -

  • Octavio Ricchetta

    1/19/2008 6:59:00 PM |

    Did you see the statins article in latest issue of BW? It is a MUST read!

    http://www.businessweek.com/magazine/content/08_04/b4068052092994.htm?chan=magazine+channel_top+stories

  • Anonymous

    1/19/2008 8:10:00 PM |

    I'd make it akin to pregnancy: ya either are or ya aint... no grey areas.  
    could be 9mos, could be 3mos but you're still pregnant.

    Scan and Track yourself...You either have a positive CAC score, lucky dude (or dudette) it's zero. If it's positive then Obliterate that Plaque (S.T.O.P.) with TYP and DR. Davis!

  • Anonymous

    1/19/2008 8:39:00 PM |

    And if you look 3mos pregnant (and you're male) there's a 100% chance you have plaque.
    And if you're female... and NOT pregnant, ditto because central obesity typically indicates Insulin Resistance the strongest plaque builder out there. 70% of the world's population are pre-diabetic or have type 2 diabetes (T2DM) and it's growing everyday.

  • Dr. Davis

    1/19/2008 10:08:00 PM |

    I can't tell you how many people have come to me and told me that a doctor told them statins were "magic" or a virtual "cure" for heart disease. Of course, they are not. They don't even come close.

    Yes, statins do provide a role. In a $26 billion industry, perhaps 20% of that is truly necessary.

  • Dr. Davis

    1/19/2008 10:09:00 PM |

    Well said.

    Maybe I should post a piece called "Are you a pregnant male?"

  • Anonymous

    1/20/2008 7:50:00 PM |

    A little off subject, but any comments on the latest report( I believe from the  Framingham study ) that says low vitamin D levels is a very definite cardiac risk factor ONLY in people with high blood pressure and not at all in anybody else?

  • Dr. Davis

    1/21/2008 1:43:00 AM |

    As with any observational study in which no intervention (e.g., treatment with vitamin D) was made, various factors as predictors of death and heart attack emerge only when powerful effects are likely.

    We see enormous effects from vit D replacement regardless of BP effects. Remember also that there is more to life and health than reduction of cardiovascular disease risk. Vit D also reduces risk of falls/fractures, osteoporosis, various cancers (esp. colon and prostate), reduces blood sugar, inflammatory responses, etc.

  • Anonymous

    1/21/2008 11:20:00 AM |

    I know this is probably not the right place to post this message but I do not know where else to. I live in the UK and I have had 'Track Your Plaque' on order for the past two weeks with Play.com (similar to Amazon). I queried why my order is taking so long and they said that the book is printed on demand. Is this correct ? If so please can you tell me when you are next doing a printing because I really do need the book before the beginning of February when I will be seeing my cardiologist and asking him for a referral for an EBCT scan. I want to go to my appointment armed with 'Track Your Plaque' !

    with kind regards,
    Anne

  • Dr. Davis

    1/21/2008 1:01:00 PM |

    Yes, this far out from its original printing, it is now printed only on demand.

  • Anonymous

    1/21/2008 1:38:00 PM |

    Dear Dr Davis,

    Have you any idea how long it takes to get a copy printed ? I have a bicuspid aortic valve with moderate stenosis and I think it would be a good idea for my cardiologist to refer me for a scan so that we can see why the stenosis is progressing if it is due to calcification of the valve - I don't see what else it could be - but he may take some convincing and I was hoping that if I had the book it would be helpful. If I don't get a referral it will be too expensive for me to pay for myself as an EBCT scan in the UK costs around £500 or $1000.

    with best wishes,
    Anne

  • Dr. Davis

    1/21/2008 1:43:00 PM |

    Hi, Anne-
    Unfortunately, a heart scan will not be very helpful for the question of aortic valve disease. Yes, it can quantify calcium on the valve, but this is not a factor in determining when replacement is necessary, nor does it help track progression, unlike in coronary arteries.

    Be sure to take a look at vitamin D--this is crucial in aortic valve issues.

  • Anonymous

    1/21/2008 2:04:00 PM |

    Dear Dr Davis,

    Oh, I see :-( My cardiologist is doing yearly echocardiograms to determine when to replace the valve, but, from my limited knowledge, I had been thinking that if I knew the exact extent of any calcification on the valve and took all steps necessary to reverse the calcification then I could reverse the progression of the stenosis and never have to have a valve replacement. I have started to take 5000iu of D3 per day yes Smile

    with best wishes,
    Anne

  • wccaguy

    1/21/2008 3:53:00 PM |

    Hi Dr. Davis,

    I have a friend whose wife has mitral valve prolapse.  Would Vitamin D3 supplementation be useful in treating this?

  • g

    1/21/2008 4:13:00 PM |

    anne,

    I bought 8 books -- and they arrived in < 1wk.  Once you read it, you'll want your best friends and family to get onboard too! Smile  No point in being immortal... ALONE.
    Also, if you're considering trackyourplaque.com membership, the TYP book is included!

    g

  • Dr. Davis

    1/21/2008 10:30:00 PM |

    Hi, WC--
    No. Vit D will not have any specific effect on mitral valve prolapse. However, it's still worth taking for all the other benefits, however.

  • trading

    1/22/2008 12:08:00 AM |

    I received a zero score in a coronary artery calcium screening. However, the clinic mailed me a report that had some comments related to mild ectasia of the ascending aorta and subtle calcification involving the descending aorta.  Any thoughts?

  • Dr. Davis

    1/22/2008 12:28:00 AM |

    Then it's likely that high blood pressure, vitamin D deficiency, and some other factors (see lipoproteins) are active issues.

  • trading

    1/22/2008 1:13:00 AM |

    Dr. Davis
    Thank you for the response. I am fascinated by your blog and will follow up on your suggestions.

  • Peter

    1/22/2008 11:20:00 AM |

    wccaguy,

    Re mitral valve prolapse: Is magnesium a factor? Bit of an obscure ref but Mg is pretty non toxic by mouth...

    Peter

  • Stan

    1/22/2008 6:35:00 PM |

    Magnesium depletion seems common also in diabetes.  Could perhaps Mg depletion and it's negative consequences, including valve damage as per Peter's reference, be caused by the excessive carbohydrate consumption as the primary factor?

    Stan (Heretic)

    http://www.chiro.org/nutrition/magnesium.shtml#carbohydrate_metabolism

  • Dr. Davis

    1/22/2008 8:49:00 PM |

    Yes, magnesium depletion can develop on high-carbohydrate diets, and it also aggravtes pre-diabetic tendencies.

    However, while magnesium supplementation can reduce some of the consequences of mitral valve prolapse (such as abnormal heart rhythms), it does not actually protect the valve.

    A bit confusing.

  • Stan

    1/23/2008 3:39:00 PM |

    Dr. Davis wrote:  However, while magnesium supplementation can reduce some of the consequences of mitral valve prolapse (such as abnormal heart rhythms), it does not actually protect the valve.

    Very interesting!  That would suggest that magnesium depletion may be a coincidental marker of something else that is the common cause of both heart damage and magnesium depletion. Much like in the serum cholesterol case, perhaps?

  • Anne

    2/1/2008 3:31:00 PM |

    Dear Dr Davis,

    You wrote: "Unfortunately, a heart scan will not be very helpful for the question of aortic valve disease. Yes, it can quantify calcium on the valve, but this is not a factor in determining when replacement is necessary, nor does it help track progression, unlike in coronary arteries."

    I've just found this article which suggests that the stenosis associated with bicuspid aortic valve can be reversed, and likens the progression of the calcification on the valve to that in atherosclerosis in arterial walls: http://content.onlinejacc.org/cgi/content/full/42/4/593

    Can you comment on this please because if it were true then the strategies employed in Track Your Plaque would work for valves too wouldn't they ?

    with best wishes,
    Anne

  • Dr. Davis

    2/1/2008 8:04:00 PM |

    Anne--

    The review you cite preceded publication of two studies that attempted to affect progression of aortic valve disease using high-dose Lipitor or Crestor. Lipitor had no effect; Crestor, 40 mg per day, did have a small effect.

    Because the Track Your Plaque program does not track aortic valve disease, I cannot say whether or not it has any effects. However, it is probably small to none--with the exception of vitamin D. I have great hopes for vitamin D's effect on slowing or reversing aortic valve disease. We are accumulating an experience with vit D, but it's too preliminary to publish.

  • Anne

    2/4/2008 8:05:00 PM |

    I saw my cardiologist today for my yearly echocardiogram. The pressure gradient across my bicuspid aortic valve has increased from 35mmHg to 38mmHg since last year which my cardiologist said was good....but he's going to refer me for an EBCT scan !  And because I have private health insurance I should be covered.....they don't do EBCT scans under the NHS here in the UK so I'm really lucky Smile

    all the best,
    Anne

  • Anne

    2/27/2008 4:38:00 PM |

    Dear Dr Davis,

    I had the results of my scan today. There's no calcification in the coronary arteries Smile But calcification showed up on the bicuspid aortic valve. My cardiologist said there's nothing I can do about that because of the turbulent blood flow, but I'm determined that I will be able to halt the calcification or reverse it and I will be watching your blog for anything you write about aortic valve disease, especially when you write about your work with vitamin D and aortic valves. I'm currently taking 4000iu D3.

    with best wishes,
    Anne

  • buy jeans

    11/3/2010 6:36:49 PM |

    Coronary atherosclerosis is a diffuse process that involves much of the length of the artery. It is therefore folly to believe that a 15 mm long stent has addressed the disease. This is no more a solution than to replace the faucet in your kitchen in a house with rotting pipes from the basement up.

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