Cholesterol lowering medicines, also known as statins, are now widely thought to be massively overprescribed and of limited benefit worldwide. The media has started to report on this, I recall an article on the news recently about a major UK study that stated this finding. To understand why this is, we first need to first start with one of the most important concepts in medicine, the NNT number (Number Needed to Treat). The NNT number is available for virtually every prescription medicine, and it tells you how useful – or dangerous – a drug actually proved to be during human trials, before it was allowed on the market.
Here’s a scenario…
You visit your doctor. He or she prescribes you some medicine and says, “You know, 99 per cent of people I prescribe this to get absolutely no benefit whatsoever.” Would you still take the medicine? I know I wouldn’t! The second problem with taking medicine that doesn’t offer any real benefit is that you may still end up with unwanted side effects.
How does the NNT number work?
In simple terms, the NNT number just means: How many people (in the pharmaceutical company’s human clinical trial) did they need to give the medicine to, in order to successfully treat one person for a specific condition. Ideally, we want an NNT number for medicine to be as close to 1 as possible. An NNT number of 1 would mean that every person who takes the medicine is successfully treated. It’s a hypothetical situation, as no medicine is perfect. At the other end of the scale, an NNT number of 100 would mean that the medicine works for just one person in every 100 people, or that 99 per cent of people prescribed the medicine actually receive no benefit at all.
An example of a very useful pharmaceutical medicine
Antibiotics work very well, and are probably the most successful class of pharmaceutical medicines ever created. Antibiotics are prescribed for bacterial infections, and they work nearly all the time. For a common stomach ulcer that is caused by bacteria, the NNT number for an antibiotic is 1.1, and that means that for every 11 people given the antibiotic, 10 people recover. So as a treatment method, it gets a big tick!
Why are cholesterol lowering drugs prescribed?
Cholesterol lowering drugs (statins) are routinely prescribed to lower cholesterol. High cholesterol is thought to be a risk factor for heart attacks, so people take statins to reduce the chance of having a heart attack. My understanding is that several hundred thousand New Zealanders are on statins, but I doubt their doctors have ever told them what I am about to tell you. In fact, I doubt the pharmaceutical companies have ever accurately advised the doctors about the true effectiveness of the medicine.
Statin drugs are a ‘blockbuster’ category of pharmaceutical medicine. They are a category of medicine that earns pharmaceutical companies much of their profit. I understand statin sales to be a US$35 billion industry annually (NZ$43 billion). Most of the big pharmaceutical companies have their own statin medicine on the market.
How effective is statin medication in preventing heart attacks?
The evidence as to whether statin drugs work or not can often be found in the fine print of the companies own newspaper ads (in the United States anyway).
When pharmaceutical companies run a human trial, they need to compare a group of people who take their medicine, with a group of people who remain untreated (the untreated group are given a placebo, or a sugar pill). The idea is that none of the study participants know whether they are given the real medicine or a placebo. Both groups of people are selected because they share a similar problem – in this case high cholesterol.
An advertisement for the biggest-selling statin in the world indicated that use was associated with a 36 per cent reduction in chance of a heart attack over the three and a third years of a large human trial. But this claim had an asterisk, and the fine print said: “3 per cent of patients taking a sugar pill or placebo had a heart attack compared to 2 per cent of patients taking the statin.”
So if two people out of every hundred have a heart attack in the group prescribed the statin drug, and three people out of every hundred have a heart attack in the group that is given the placebo, then we can say the statin drug prevented just one heart attack out of every 100 people, over the time that the human trial ran. Sadly, that means that 99 out of every 100 people actually received no benefit from taking the statin medication for all of that time.
Misleading presentation of statistics
The confusion lies in the way the results are presented. Stating that a statin medicine is associated with a 36 per cent reduction in the risk of having a heart attack sounds a lot more compelling to consumers than telling them it has an NNT of 100 (meaning 1 person in 100 benefits from the drug).
One chart we found shows the real protection afforded to people who take statin medication, depending on their underlying health conditions. Click here to see chart
The sad reality is that pharmaceutical companies have become giant marketing machines, and they deliberately misuse statistics to mislead us into thinking that a given drug is more effective (or safer) than it really is. I cannot think of a better example of this than the marketing of statin drugs to consumers.
I provide you with this information to (hopefully) arm you with the right questions to ask your doctor. There are cases where some people get benefit from statin drugs, so if you are on them and you are concerned please talk to your doctor – don’t just stop taking prescription medication!
Daniel King MSc (Hons)
This is a very good article in Bloomberg Businessweek which provided some useful data.