Concept In Cardiology Of “Lives Saved” Is Totally Misleading

[Guest guest]

http://www.redflagsweekly.com/kendrick/2004_aug18.html

 

MALCOLM KENDRICK, MD

 

THE CONCEPT IN CARDIOLOGY OF “LIVES SAVED” IS TOTALLY

MISLEADING

 

It Inflates The Benefits Of Drug Treatment and Is

Intellectually Dishonest

 

By Red Flags Columnist Dr. Malcolm Kendrick

 

(email - malcolm)

 

How is it that cardiologists save lives, when

oncologists only manage to increase median survival?

Okay, not the snappiest question ever. But you try

engaging in a discussion on median survival rates

without creating instant narcolepsy.

 

Here is another question for you. If I were to use a

defibrillator on a man having a heart attack, and I

get his heart beating normally again, have I saved his

life?

 

Is this a trick question? In a way. Perhaps you would

say that it all depends how much longer he lives. If

he only lives an extra five minutes, then dies, did I

save his life? No, yes, maybe? Did I increase his

lifespan? Yes, of course, if only by five minutes.

 

What if he lives for another year? Did I save his

life?

 

The reality, of course, is that you cannot actually

stop anyone from dying. You can only give them more

time. How much more? Well, you’re never going to know

unless you keep track of them for the rest of their

life.

 

‘So what,’ I can hear you cry. So quite a lot,

actually. Because cardiologists talk about saving

lives all the time. Superficially this may seem

reasonable. However, in reality, this represents a

statistical sleight of hand that results in a massive

distortion of the results of clinical trials,

stretching benefits to breaking point – and beyond. It

makes the bogus use of relative risk figures fade into

insignificance. You probably think this is a bit of an

exaggeration, but bear with the argument.

 

Moving back to oncologists for a moment. They

recognised early on, I am not quite sure how or why,

that their drug treatments rarely cure cancer (a

moment of unexpected humility from the medical

profession). Anti-cancer agents zap tumors, but they

most often do not get rid of the cancer altogether, as

it often returns.

 

Therefore, in most cases, all that a new drug

treatment in cancer can achieve is an increased length

of survival. Thus, when they do a clinical trial on a

new drug treatment, oncologists normally report their

studies according to the increase in median survival.

Median survival means the time at which fifty per cent

of patients are still alive – or fifty per cent have

died.

 

Why don’t they use the average? Because, gentle

reader, if you want to know the average lifespan, you

have to wait until almost everyone has died before you

can do the calculation. As some patients may actually

be cured by the treatment, you might have to wait for

fifty years before they die. Which is a bit long for

any clinical trial.

 

Anyway, in cancer treatment, if they did a trial in

which one hundred more of the ‘treated’ patients were

alive at the end of, say, two years, no-one would

dream of claiming that one hundred lives had been

saved.

 

Yet cardiologists have no hesitation in claming that

lives can be saved. The home page of the Heart

Protection Study (HPS), starts with the quote, ‘Tens

of thousands of lives could be saved each year by

changing prescribing guidelines for statins,’ says Dr

Rory Collins, lead investigator of the HPS study.

 

The implication here is that every extra person who

has not died, has been cured, and will live out a full

and healthy life. But this is complete nonsense. The

reality is that drug treatment, at best, slows disease

progression, and may give you some extra time.

 

Therefore, when Rory Collins says ‘Tens of thousands

of lives could be saved, what he actually should say

is that, tens of thousands of people may have their

lives extended by about six months to a year by using

statins (and only if you treat more than one million

people).

 

Why doesn’t he say this? I suspect you may already

know the answer to this question. He doesn’t say this

because – if you claim that you are saving lives – the

benefits sound fantastic. However, if you claim that

you are merely delaying disease progression – it seems

rather less wonderful.

 

I will just try to feed some real figures into this

theoretical discussion, to give you a better idea of

the level of distortion achieved.

 

A study published in May 2003, in the Journal Of The

American Medical Association,

 

looked at all clinical trials on blood pressure

lowering. Nineteen of these trials looked at drug

treatments (various) versus placebo. There were 42,972

patients in all these trials and they lasted, on

average, three and a half years or so. In total,

therefore, these trials represented 133,741 years of

drug treatment.

 

Adding the results from the trials together, there

were 1453 deaths in the placebo group, and 1303 in the

treated patients. Which means that there was a grand

total of one hundred and fifty more people alive in

the treated groups.

 

Now, if each of the one hundred and fifty people who

survived was ‘cured’ and lived an extra thirty years

this wouldn’t be too bad a result. I don’t think.

 

To work out the exact benefit, you could do a

calculation as follows:

 

150 lives saved x 30 extra years = 4,500 extra years

of life.

 

As it took nearly one hundred and forty thousand years

of drug treatment to achieve four and a half thousand

extra years of life, this means that each extra year

took about thirty years of drug treatment. Not

brilliant, but not too bad. Although I don’t think it

would convince me to take a tablet each day, for the

rest of my life.

 

If, however, you know that no-one was actually cured,

and all you have done is delay death by about a year

(max), the equation looks rather different.

 

150 lives increased by one year = 150 extra years of

life

 

At 140,000 years of drug treatment, this means you

need almost one thousand years of drug treatment to

gain one year of extra life. In my opinion this

changes the result from ‘not bad’ to ‘a complete waste

of time and money.’ Especially when you consider that

all drugs have side effects. Some worse than others.

 

You could add, if you were a troublemaker like me,

that in reality it takes about one thousand years

worth of side-effects to create one extra year of

life. And, at about $1,000/year for the drugs, it also

costs almost one million dollars per year.

 

Perhaps you could put this another way. According to

the figures, the average person taking a blood

pressure lowering medication for thirty years will

gain 30/1000th of a year of extra life – or about nine

days. Thirty years of treatment for nine days extra

life! Whoopee! Raise the flags and fire a cannon in

the air. There have got to be better ways of spending

money to improve health than this.

 

To be frank, I am not sure if the cardiology community

is even aware that the concept of ‘lives saved’ is

utterly misleading. It is so ingrained into the

thinking that no-one even questions it. Most

cardiologists would (I know I’ve tried it) just look

at you in bemusement if you suggested that talking

about lives saved hugely inflates the benefits of drug

treatment and is therefore intellectually dishonest.

 

They cannot, or will not, see that there is a problem

here. And I am sure that, until you read this, you

perhaps didn’t realise there was even an issue, let

alone a problem. ‘Saving lives, sure, that seems

reasonable, what’s wrong with that.’

 

Maybe I should try to arrange a meeting where

oncologist and cardiologists discuss how they set-up,

then present, the results of drug trials. Although, I

suspect that the oncologists may be seduced by the

cardiologists, rather than the other way round. ‘You

mean you’ve found a way to make the benefits of

treatment seem three thousand per cent better….wow…

way to go.’