Chicken Little

Clinical studies can be designed in a number of ways. The ease and cost of these studies differ dramatically, as does the confidence of the findings.

The most confident way to design a clinical study is to tell neither the participants nor the investigator(s) what treatment is being offered, then to administer treatment or placebo. Neither the people doing the research nor the participants know what they are receiving. Of course, there needs to be some way to find out what was given at the end of the study in order to analyze the outcome.

This is called a “double-blind, placebo-controlled” clinical study. While not perfect since it tends to examine a treatment phenomenon in isolation (e.g., the effects of a single drug in a select group of people), it is the best sort of study design that is most likely to yield confident results, both negative and positive. This sort of design is followed, for instance, for most prescription drugs.

There are pitfalls in such studies, of course, and some have made headlines lately. For instance, beyond tending to examine single conditions in a select group of participants, a double-blind, placebo-controlled study can also fail to uncover rare effects. If a study contains 5000 participants, for instance, but a rare complication develops in 1 person out of 20,000, then it’s unlikely such an ill-effect will be observed until larger numbers of people are exposed to the agent.

Another pitfall (though not so much of study design, but of human greed) is that study outcomes that are not favorable can be suppressed by simply failing to publish the results. This has undoubtedly happened numerous times over the years. For this reason, a registry has been created for all human clinical trials as a means to enforce publication of outcomes, both favorable and unfavorable.

Despite its weaknesses, the double-blind, placebo-controlled study design remains the most confident way to show whether or not some treatment does indeed yield some effect. It is less prone to bias from either the participant or the investigator. Human nature being what it is, we tend to influence results just to suit our particular agenda or interests. An investigator who knows what you are given, drug or placebo, but owns lots of stock in the company, or is hoping for special favors from the pharmaceutical company sponsor, for instance, is likely to perceive events in a light favorable to the outcome of the study.

Now, most studies are not double-blind, placebo-controlled studies. These are notoriously difficult studies to engineer; raise lots of ethical questions (can you not treat a person with an aggressive cancer, for instance, and administer a placebo?); often require substantial numbers of participants (thousands), many of whom may insist on payment for devoting their time, bodies, and perhaps even encountering some risk; and are tremendously expensive, costing many tens of millions of dollars.

For this reason, many other study designs are often followed. They are cheaper, quicker, may not even require the active knowledge or participation of the group being studied. That’s not to say that the participants are being tricked. It may simply be something like trying to determine if there are more heart attacks in people who live in cities compared to rural areas by comparing death rates from heart attack from public records and population demographic data. Or, a nutritional study could be performed by asking people how many eggs they eat each week and then contacting them every month for 5 years to see if they’ve had a heart attack or other heart event. No treatment is introduced, no danger is added to a person’s established habits. Many epidemiologic studies are performed this way.

The problem is that these other sorts of study designs, because they generate less confident results, are not generally regarded as proof of anything. They can only suggest the possibility of an association, an hypothesis. For real proof to occur, a double-blind, placebo-controlled may need to follow. Alternatively, if an association suggested by a study of lesser design might, by reasons of a very powerful effect, be sufficient. But this is rare. Thalidomide and catastrophic birth defects are an example of an association between a drug and fetal limb malformation that was so clear-cut that no further investigation was required to establish a causative association. Of course, no one in their right mind would even suggest a blinded study.

Where am I going with this tedious rambling? Lately, the media has been making a big to-do about several studies, none of which are double-blind, placebo-controlled, but were cross-sectional sorts of observations, the sorts of studies which can only suggest an effect. This happened with Dr. Steve Nissen’s study of Avandia (rosiglitazone) for pre-diabetes and risk for heart attack and the recent study suggesting that cancer incidence is increased when LDL cholesterol is low. Both were observations that suggested such associations.

Now, those of you following the Heart Scan Blog or the www.cureality.com website know that we do not defend drug companies nor their drugs. In fact, we’ve openly and repeatedly criticized the drug industry for many of its practices. Drugs are, in my opinion, miserably overused and abused.

But, as always, I am in the pursuit of truth. Neither of these studies, in my view, justified the sort of media attention they received. They are hypothesis-generating efforts—that’s it. You might argue that the questions raised are so crucial that any incremental risk of a drug is simply not worth it.

Despite the over-reaction to these studies, good will come of the fuss. I do believe that heightened scrutiny of the drug industry will result. Many people will seek to avoid prescription drugs and opt for healthy changes in lifestyle, thus reducing exposure to costs and side-effects.

But beware of the media, acting as our Chicken Little, reporting on studies that prove nothing but only raise questions.

Comments (1) -

  • jpatti

    9/11/2007 10:26:00 AM |

    There's another issue with double-blind studies, for things other than drugs or supplements, they're impossible.  

    Your example of the number of eggs in a person's diet is a good example; there's no "placebo" for eggs.  Similarly, if I increase my level of exercise, I notice that - it can't be blinded.  For diet and other lifestyle changes, we will never be able to gain the amount of evidence as for drug trials.

    I think this is why many doctors don't think so much about prescribing these types of things, except for a cursory instruction to "eat better, lose weight and exercise," they're just not as strongly convinced of the benefit of these changes because they can't be proven as strongly.  But... not being able to prove something doesn't mean it's not important to health!  

    As a diabetic, I measure my bg multiple times a day and make changes to my food intake, exercise and medication dosage to hit established bg goals.  While I think tightly-controlling bg is probably the number one thing I can do for my heart health, it can never be proven in a double-blind study.

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Trains, planes, and heart scans

Trains, planes, and heart scans

A Heart Scan Blog reader posted the following question:

It is not clear to me why getting a cardiac scan is the necessary first step, if in fact the next step would be to bring down small LDL particles which is revealed on a NMR lipoprofile or VAP test. Why isn't the NMR or VAP test the first thing?

Good question. Think of it this way:

Lipoproteins, as measured via VAP (Vertical Auto Profile) or NMR (Nuclear Magnetic Resonance), provide a snapshot of risk from a metabolic viewpoint at that moment. Lipoproteins shift with the tides of age, menopause, weight changes, even what you ate last evening for dinner (especially small LDL). There are also other factors that cause coronary plaque, as well, not revealed through lipoprotein testing, such as vitamin D deficiency, smoking, high blood pressure, phosopholipase A2, lipoprotein(a), inflammatory factors, thyroid dysfunction, omega-3 fatty acid deficiency, etc.

A heart scan, providing a coronary calcium score, provides an indirect measure of coronary plaque that is the sum total of lipoprotein and other plaque-causing factors that have accumulated up to the time of your scan--regardless of the cause.

It means that two females, each 60 years old, with 70% small LDL, HDL 42 mg/dl, triglycerides 150 mg/dl, and mild hypertension, have identical markers for potential coronary risk, but can have widely different heart scan scores. One might have a score of zero, while the other might have a score of 300.

Why would the same panel of causes measured at one moment yield wildly different quantities of plaque? Several reasons:

1) The lifestyles, eating habits, and weight of each woman differed during their earlier years, not currently reflected in this moment's lipid or lipoprotein patterns. Perhpaps one experienced several years of extraordinary stress from a failed marriage, or suffered through two years of depression that caused her to smoke and overeat.

2) There are hidden factors that affect coronary plaque growth that we are presently not able to detect, e.g., vitamin D receptor genotype, cholesteryl-ester transfer protein variants, variation in inflammatory factors. If we can't measure it, we won't know whether it might influence coronary plaque risk.


With all the changes that occur over a person's life, with the uncertainties of yet-to-be-identified causes for coronary plaque, how can you possible know what your risk for heart disease truly is? Yup--a heart scan. Do it and you will know.

Comments (10) -

  • Anonymous

    9/6/2009 6:22:50 PM |

    So now the question is, how would your treatment differ for these two women?

    BTW I had thought the NMR/VAP were the lipoprotein equivalent of the HbA1c for blood sugar -- oh well!

  • Lou

    9/6/2009 10:38:43 PM |

    Hi Dr Davis

    I have just discovered your brilliant site.

    I saw on another post that you have some Track you plaque members from other countries. Do you have any idea if the blood tests you recommend are available to patients outside of the States (specifically in the UK or Europe)?

    Thanks
    Lou

  • Anonymous

    9/7/2009 1:45:12 AM |

    Hi Dr. Davis,

    Do you find an earlobe crease to be a reliable determinant of coronary calcium?  I have one and notice you have one as well (on your pic).

    Thanks,
    Dan

  • Heart Scan

    9/7/2009 6:12:51 AM |

    Isn’t it natural for us to believe we are healthy and not suffering from any disease? I had a similar thought process until my physician asked me to get a heart scan done after he found that my basic cardiograms were not perfect. I discovered that there were calcium deposits in my coronary arteries and I was at a serious risk of a heart attack. I was shocked and went ahead with the Cardiologist's suggestion of an advanced diagnostic scan. Though it’s always tough to undergo such experiences, I was not at any kind of discomfort at the Elitehealth.com advanced heart scan facility. I am not an expert in medical appliance and machines but could feel that the equipment was world-class and I was in safe hands. That feeling is really very important for me and that’s how it actually went on. The facilities for Full Body Scan were as good as they can get.

  • Dr. William Davis

    9/7/2009 2:13:21 PM |

    Anony--

    Easy. A woman with a zero score might make some efforts to correct her lipid/lipoprotein patterns to less strict endpoints, though she should still supplement vitamin D, iodine, and omega-3 fatty acids. The other woman should follow our Track Your Plaque endpoints if her goal is to stop plaque growth.


    Lou--

    Sorry, but I am not familiar with the availability of lipoproteins worldwide. I do know that people from outside the U.S. have managed, but it differs in every country. Please let us know if you have any success.

  • Anonymous

    9/7/2009 3:21:15 PM |

    I had a heart scan 7 years ago at  Hopkins, how often should it be done? I didn't have any calcium- I  was 49 at the time but I have high levels of small particle LDL and HDL.

    Incidentally they called a week after reporting the results of the heart scan and said I had a bunch of 'spots' on my liver which requires CAT scans and Ultra sounds to further investigate. Turned out to be something rather normal- I forget what they are called- just it involved a bunch of tests during a four week period and a lot of worrying.

    Anytime you do a body scan be prepared to find other stuff- which may or may not be a good thing depending on your frame of mind and it you are the type of person who needs to know everything.

    C'est la vie

  • Anonymous

    9/9/2009 1:42:12 PM |

    Actually, I can think of at least one scenario where getting a VAP or similar test WOULD be the first step... youth.


    I am inelligible for a heart scan because of my age (female under 40), yet I have a strong family hx of heart disease and have already presented with some signs of risk.  IMO, a VAP test would be the best thing for someone under 40 who is concerned about heart disease.

  • Materialguy

    9/15/2009 5:21:02 PM |

    I'm looking at "The New Heart Disease Handbook" by Christopher Cannon MD and Elizabeth Vierck 2009. They mention calcium score and calcium scan a few times. Their wording focuses on the calcium scan being useful in identifying areas of plaque buildup. There are probably only a total of 300 words on the subject all totaled. Sounds like progress slowly inching along.

  • Carolyn

    9/23/2009 6:11:03 PM |

    Wheat bran and any other dry whole grain puts my digestive tract in acid overdrive.

  • Female heart attack

    9/24/2009 10:06:31 AM |

    We all have heard of heart attacks. Among women, menopausal women are more prone to heart attacks due to lower levels of estrogen. Some symptoms of female heart attacks are: pressure felt in the chest area, feeling weak, low energy, uncommon symptoms are: nauseous sensation, giddiness, etc. Women often put themselves in the last list because they have many responsibilities, but as soon as any women notice such symptoms, should go for checking.

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