01.03.2016 Natural Health

Too Much Trust

Peter Dingle PhD asserts that our willingness to trust and our fear of statistics is leading to a wrongful and potentially deadly overuse of drugs.

For over a decade now, I have been raising people’s awareness over the use of medications that really are of no benefit to our health and may actually be doing us harm. In fact, many research-based estimates suggest the top 12 or even more medications we currently use fall into this category.

This is not a wild ambit claim but something which shows up consistently in the medical journals. That is, the medical system is so corrupted that we spend billions of dollars each year on drugs that do not help in any way. The classic example I frequently use are statin drugs, which are used to lower cholesterol (including statins like Pravachol®, Zocor® and Lipitor®). Statins are great at lowering cholesterol but that is not the disease. The disease is heart attack or stroke and these drugs have virtually no impact on them. Didn’t you watch the ABC Catalyst program on the topic before it was quickly whisked off the air due only to pressure from the pharmaceutical industry?

Statins are great at lowering cholesterol but that is not the disease.
The wrongful and potentially deadly overuse of these drugs comes down to statistics and trust.

Let’s start with trust. We trust our GPs know a lot about the drugs they prescribe and recommend and, in particular, they understand how to interpret statistics. As I will show you at length this is not the case. The next part of the trust problem is they rely on information from the drug companies who are involved in all the steps along the way, from doing the research to educating the GPs about the drugs. They provide the best possible scenario to convince the GPs that their drugs are effective and safe. Do you see where the problem lies, especially in the interpretation of statistics?

Our GPs and specialists are well trained but clearly they do not understand the use of statistics or they would not recommend many of the drugs they do. Let me give you an example on my pet drug, the statin.

Various independent studies in prestigious, peer-reviewed journals have shown that statin use in primary prevention - that is, to save lives - has minimal or no value in reducing mortality and certainly nothing that is considered anywhere near clinically significant to warrant their use. It does not matter how one manipulates the statistics, the results just aren’t there. In data gathered in 2009 from six trials, a review of the efficacy of statins in lowering the risk of death found virtually no difference between the treatment group and the control group. There are many more of these studies.

Relative Risk not Real Risk

The first problem with statistics is that the studies on drugs report “relative risk”, not “absolute risk” or “real risk”. The relative risk reduction is highly misleading, if not deceptive.

Here is an example of relative risk: if you have four people in a study who die in the placebo group (no drug) compared to three people who die in the drug treatment group - that is, four were expected to die but with the drug only three did - then there is a 25% relative risk reduction. However, to get this effect of saving one life you would have to treat 1,000 people and the real risk reduction is 0.1%.

Relative risk is like adding 1+1 to get 11 or 2+5 to get 25 or more. How can the pharmaceutical companies and the researchers working for them get away with this?

This is probably because (at least in my experience) most people are afraid of statistics.

Here is a real life example of how the stats are abused. Pravachol® (a statin drug) was promoted in the media, with much fanfare, as having a 22% drop (relative risk, not real risk) in mortality. However, when one looks at the numbers and statistics behind the calculations, treating 1,000 middle aged men who had high cholesterol and no evidence of a previous heart attack with the statin for five years resulted in seven fewer deaths from cardiovascular causes, and two fewer deaths from other causes than would be expected in the absence of treatment. The real risk reduction, however, was a mere 0.9% - less than 1% or nine lives out of 1,000 when treated for five years. The research was sponsored by Bristol-Myers Squibb Pharmaceutical.

Number Needed to Treat (NNT)

Now if this is hard to understand then there is an even simpler number, which is used in medicine, the Number Needed to Treat (NNT). This is how many people you need to treat to stop one negative outcome occurring. The negative outcome might be heart attack, stroke, cancer or even recurring ear infection. The NNT offers a measurement of the impact of a medicine or therapy by estimating the number of patients who need to be treated in order to have an impact on one person. In this case, the higher the number the worse it is and the lower the number the more effective the medication.

So an NNT of 1 is fantastic and an NNT of 100 is absolutely useless.

If a new drug reduced the death from heart attacks by say 50% (absolute statistics) then the number needed to treat is around 2 (NNT=2). So you only need to treat two people to have a benefit and save one life. This is great. If the new drug cuts the heart attack rate by only 25%, that is 1 in 4, then the NNT is 4. If the drug is only one percent effective which means of the 100 people given the drug it will only potentially (remember we are not even considering the side effects here) save one life, like the statin drugs, then the NNT is 100.


Fortunately, the NNT is well established in medicine but not widely promoted.

One website however TheNNT.com puts all this information in one place - even for the most sceptical GP and specialist - and it is available free to everyone.

Just as important, it is a group of physicians, medical doctors, who have collected the information. They only use the highest quality, evidence-based studies (frequently, but not always Cochrane Reviews), and they accept no outside funding or advertisements so they are independent of pharmaceutical companies.

In addition, for every therapy they review, they provide a color-coded summary for you to use (borrowed from the traditional stoplight). Unlike most sites, this group also reports harm that may be caused by the drug or the procedure and then they rate it into a colour-coded stoplight.

They have developed a framework and rating system to evaluate therapies based on their patient-important benefits and harms. The therapies rated green are the best you can get - there is clear evidence of benefits which clearly outweigh any associated harms. A good example is Steroids for Asthma Attack: if you give steroids to 8 patients with asthma attack in the emergency department, you prevent one from having to be admitted to the hospital. There are definitely side effects to steroids - high blood sugar, hyperactivity - but they are considered minor in comparison. The NNT for this treatment is 8. Remember the lower the number the better.

Therapies rated yellow require more study because they don't think the data is conclusive or substantial enough to be able to give a clear rating yet. So they are not recommended but if you do use them go with caution.

Red suggests that while there may be some benefits, they are far outweighed by the harms. One extreme example: if a medicine were to save 2% of people's lives, but cause strokes in 10% of people, it's hard to say that this medicine clearly is helpful overall.

Black is the "worst" or "lowest" rating. Therapies rated black have very clear associated harms to patients without any recognisable benefit.

What is frightening is that most of the major medications and procedures used for cardiovascular disease fit into the black.

Black list drugs

While there are many drugs and procedures listed I will start with some of the common procedures for cardiovascular disease as this is the biggest killer and there is just not enough space here to cover all the listings on TheNNT.com web site.

What is frightening is that most of the major medications and procedures used for cardiovascular disease fit into the black.

For Statin Drugs for Acute Coronary Syndrome, the NNT is 0% - in other words not one person who took the drug was helped (life saved, heart attack, stroke, or heart failure prevented); however, an unknown number were harmed (medication side effects/adverse reactions). This was put on the black list.

Statins Given for 5 Years for Heart Disease Prevention (With Known Heart Disease) was given an NNT of 83. In fact, they reported 96% saw no benefit while 1% were harmed by developing diabetes and 10% were harmed by muscle damage - just two of the side effects. This is also put on the black list as the harm outweighs any insignificant benefit of the drugs.

Statin Drugs Given for 5 Years for Heart Disease Prevention (for people who had no history of heart disease) was also put on the black list. The drugs have a NNT of 104 for non-fatal heart attack. However, they did not save a single life and 1 in 100 patients were harmed by developing diabetes and 1 in 10 had severe muscle damage.

In contrast, the Mediterranean Diet for Secondary Prevention After Heart Attack got the green light and a NNT of 30 for mortality and no negative side effects and 1 in 18 patients helped.

And this is not to mention benefits in other conditions such as cancer and diabetes.

Beta Blockers for Acute Heart Attack (Myocardial Infarction), also commonly prescribed by specialists, was put on the black list and listed with no benefit, but 1 in 91 harmed by cardiogenic shock.

Hormone Replacement Therapy for Cardiovascular Prevention of a First Heart Attack or Stroke, was black listed with no benefit found. However, 1 in 250 were harmed (heart attack due to HRT - oops, exactly what they were supposed to prevent), 1 in 200 were harmed (stroke due to HRT) and 1 in 100 were harmed (blood clot in the leg/lung). To support this, a recent study, which investigated 27 trials, found only one trial showing a 0.7% benefit and 26 trials that suggest no aggregate mortality benefit to beta blockers. All the more recent, and larger, trials that utilised double-blind techniques (COMMIT, 2004) found no benefit.

Even putting a stent (a little piece of artificial artery) in an artery got on the black list. In the case of Coronary Stenting for Non-Acute Coronary Disease Compared to Medical Therapy, none were helped - that is no life saved, no heart attack prevented, and no symptoms reduced. However, 1 in 50 were harmed including complications such as bleeding, stroke and kidney damage.

Even putting a stent (a little piece of artificial artery) in an artery got on the black list.

Coronary Artery Bypass Graft Surgery (Heart Bypass) for Preventing Death over Ten Years was marginally better. The NNT was 25 to prevent death. However as a result of the operation, 1 in 83 died, 1 in 100 had a stroke, 1 in 43 had kidney failure, 1 in 28 were harmed in the operation, 1 in 14 required extended life support and, get this, 1 in 3-5 had cognitive decline. Not such a good outcome if you look at the whole picture and any wonder it was put on the black list.

Green light for aspirin after heart attack

Aspirin Given Immediately for a Major Heart Attack (STEMI) got the green light. So if you have a heart attack, taking an aspirin straight away has some benefit. The NNT was 42 for mortality as 1 in 42 were helped (life saved), but 1 in 167 were harmed (non-dangerous bleeding).

However, with Aspirin to Prevent a First Heart Attack or Stroke, the NNT was 1667 for cardiac benefit, that is 1 in 1667 were helped (cardiovascular problem prevented), 1 in 2000 were helped (prevented non-fatal heart attack) and 1 in 3000 were helped (prevented non-fatal stroke). But no deaths were prevented and 1 in 3333 had a major bleeding event.

The NNT for Blood Pressure Medicines for Five Years to Prevent Death, Heart Attacks, and Strokes was 125, 1 in 67 prevented stroke, and 1 in 100 prevented heart attack. However, 1 in 10 had side effects and stopped taking the drug. Treatment of Mild Hypertension for the Primary Prevention of Cardiovascular Events was given the yellow light and there was no NNT as no benefit was found. However, 1 in 12 experienced medication side effects.

On a positive note, oral anticoagulants (warfarin) for primary stroke prevention (no prior stroke) got the green light and the NNT was 25 for prevented stroke and 1 in 42 were helped (preventing death from any cause). However, 1 in 25 were harmed (having bleeding), and 1 in 384 were harmed through intracranial hemorrhage.

It seems we spend billions, even trillions of dollars, on drugs and procedures that don’t work and are likely to be doing more harm than anything just because of trust and a lack of understanding of statistics. While I am likely to criticised for presenting this information and you might question your doctor or specialist, remember I am just the messenger presenting factual numbers. See for yourself at www.TheNNT.com.

DISCLAIMER: Peter Dingle PhD is a researcher, educator and public health advocate. He has a PhD in the field of environmental toxicology and is not a medical doctor.

Peter Dingle

Dr Peter Dingle (PhD) has spent the past 30 years as a researcher, educator, author and advocate for a common sense approach to health and wellbeing. He has a PhD in the field of environmental toxicology and is not a medical doctor. He is Australia’s leading motivational health speaker and has 14 books in publication.