Friday, April 27, 2012

The VIOXX hysteria

There is a ridiculous article here which claims, in effect, that the executives of Merck & Co should have been hanged, drawn and quartered for releasing the anti-arthritis drug Vioxx.

It is all rather water under the bridge now so I won't go into great detail but but I believe Vioxx was unfairly impugned and should still be available to the many people it helped.

The attack on it was underpinned by a practice that I have often criticized on this blog:  Looking at relative risk to the exclusion of absolute  risk.  If the absolute risk is tiny, the relative risk seems of only academic interest to me.  There are risks in everything we do so something that has only a tiny absolute risk attached to it should be one of our better options in life, it seems to me.

Anyway, I will comment here only on the one big study that was most used to condem Vioxx.  The VIGOR study compared Vioxx with an accepted "safe" drug in its class: Naproxen.

And it found that using  Vioxx raised the absolute risk of a heart attack by one third of one percent -- from .01 to .04%  I would have interpreted that finding as showing that both drugs were low risk with only trivial differences between them but medical researchers love their relative risk statistics.  Without a heavy focus on RR, most of their findings would be trivial so RR is almost a religion with them. 

So they treated these essentially trivial results in a most frightening way: saying that Vioxx was FOUR TIMES as likely to give you heart attacks as its alternative.  And if you ignore that all the risks involved were tiny, that does sound alarming.  In fact, however, it was the usual medical research practice of making mountains out of molehills.  My recommendation from the data would have been that VIOXX is safe, except perhaps for  people with known heart problems

But that's not all.  While the heart attack rate  with Vioxx was elevated, the overall mortality was not!  In other words, Vioxx was not more likely to kill you than its control.  It may have led to a few more heart attacks but it REDUCED your risk of dying from other causes.  So even in relative risk terms it is a safe drug.  When you're dead you're dead.  It does not matter what you died of -- so overall mortality should have been the dominant criterion for evaluating Vioxx.  That it was essentially ignored just shows how hysterical people can get about drug companies.  They pick on trivialities to bring down what they hate as "Big Pharma".

Merck was unfairly persecuted by small minds and Vioxx should still be available to those it helped.  Arthritis is a most disabling condition and for some people Vioxx gave better relief than other drugs in its classs.

I could go on and discuss the other nitpicking associated with the VIGOR study but Humpty Dumpty is now well and truly off his wall so I see no point in going further.  I do however feel very sorry for the people at Merck and also sorry for the people who were   denied the chance to continue with something that was best for their disability.  Vioxx would not have once been so widely used without it being a very helpful drug.

LOL!  Health supplements 'could cause cancer': Study finds some products may increase chance of getting disease

Is the anti-oxidant religion fading at last?

Millions of people who take dietary supplements to ward off cancer may be toying with a ‘two-edged sword’ that might do them harm, experts have warned.

People were being misled by ‘messages from supplement manufactures’ stressing the health benefits of their products, including cancer prevention, according to a team of U.S. scientists.  They said there was no good evidence that supplement pills and capsules reduced the risk of cancer in healthy individuals.

They pointed out that antioxidants such as beta carotene, and vitamins C and E might even have biological effects that promote cancer.

Antioxidants are believed to counter the destructive effects of rogue oxygen molecules called free radicals.  Oxidative stress by free radicals, which attack cell membranes, proteins and DNA, has been linked to cancer and heart disease.

But the U.S. authors, writing in the Journal of the National Cancer Institute, argue that the supposed benefits of antioxidant supplements are largely a myth.

The panel of five experts, led by Dr Maria Elena Martinez, from the University of California at San Diego, wrote: ‘Undoubtedly, use is driven by a common belief that supplements can improve health and protect against disease, and that at worst, they are harmless.  ‘However, the assumption that any dietary supplement is safe under all circumstances and in all quantities is no longer empirically reasonable.’

Health supplements are booming in the U.S., with annual sales estimated at £18.6 billion, said the scientists, who assessed the evidence relating to several supplements including antioxidants, folic acid, vitamin D and calcium.

A number of animal, laboratory and observational studies had appeared to show that dietary supplements could lower cancer risk, they said.  However, these findings were not confirmed by the ‘gold-standard’ in evidence-based medicine, randomised controlled trials (RCTs).

Only a small number of RCTs had been carried out to test the effectiveness of dietary supplements, said the experts - and several of these had reported increased risks.

‘Supplementation by exogenous anti-oxidants may well be a two-edged sword,’ the scientists wrote. ‘These compounds could, in vivo (outside the laboratory), serve as pro-oxidants or interfere with any number of protective processes such as apoptosis induction.’ Apoptosis, or programmed cell death, causes malfunctioning cells effectively to ‘commit suicide’.

Experimental studies had shown that different tissues with different cancer-triggering pathways may not respond the same way to a particular nutrient.  ‘In fact, a nutrient may be associated with protection in one tissue and harm in another,’ said the experts.

They added that supplement users were ‘sometimes quick to discredit caution’ and distrustful of mainstream science which they suspected of being corrupted by links to the drug industry.

Users may also assume the supplements they bought to be as well regulated as over-the-counter medications.

‘These beliefs underscore the need for efforts by scientists and government officials to encourage the public to make prudent decisions based on sound evidence with respect to use of dietary supplements for cancer prevention,’ the scientists concluded.


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