β-blockers, “800’000 deaths” and the Truth Behind the Headlines

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A couple of weeks ago, the results of a large-scale clinical trial were published online. What has followed since has been a brilliant example of how the media can destroy the credibility of science and scientific research through attention-grabbing headlines and a complete disrespect for the facts. The study in question was focused on β-blockers, a heart-rate slowing family of drugs, and their use before and shortly after certain surgical procedures.

The Daily Telegraph got the ball rolling with its frenzy over the study, publishing headlines that cited there had been “800’000 unnecessary deaths” due to the use of β-blockers before surgery. The story presented here certainly whipped up a storm, but in doing so it has needlessly scared many people, including those who take  β-blockers as a routine medication for conditions such as hypertension. Getting behind the headlines is always important with science and medicine-based news so let’s take a look at the trial itself…

The research, called POISE (Perioperative Ischaemic Evaluation) was carried out jointly by several organizations, including the British Heart Foundation, AstraZeneca (who supplied the drug) and the Canadian Cardiovascular Research Authority. The multi-centre, randomized trial was carried out between October 2002 and July 2007 and involved 8’351 participants in 190 hospitals in 23 countries across the commonwealth. Around half of participants were given a standard dose of the study drug and the other half was given a placebo. Entrance criterion was strict- participants must be over 45 years of age, about to receive non-cardiovascular surgery and were expected to have a hospital stay longer than 48 hours. They must also have a history of heart disease, or about to have vascular surgery, or have 3 out of 7 risk factors. All of these things would mean they would be probably be given B-blockers before their surgery, under normal circumstances. Individuals were excluded for many reasons, especially those with a low heart rate, heart block, asthma, allergies to certain medications and those who had bypass surgery and had previously taken β-blockers or verapamil (a heart-slowing drug).

The AstraZeneca drug being administered, metoprol succinate, is not licensed in the UK. The results of this trial showed that those people who received the study drug had a significantly reduced risk of cardiac arrest after surgery when compared to the placebo group. However, they were a third more likely to die within a month of surgery and twice as likely to suffer a stroke.

It is important to remember here that β-blockers are not given as a matter of routine in the UK. When they are administered before surgery it is because that individual is suffering from cardiovascular disease (or similar) that is expected to complicate surgery. Risks and benefits are at the forefront of every medical practitioners mind when assessing a patient for surgery. However, there is a huge difference between an informed decision and a misinformed one, and the reporting on this trial by the popular press has been ill-judged, sensationalist and downright dangerous.

These results are extremely important and no doubt further research will take place now to assess the risk further. β-blockers are a vitally important class of drugs and their treatment for conditions such as hypertension and cardiovascular stress has saved huge numbers of lives over the years. Their ability to slow the heart rate and increase the function of the heart muscle means that they are also very important during times of surgical stress. If this research leads to their use being more strictly controlled, in this particular circumstance, that is no bad thing but it is important that each situation is treated on its own merits.

If you want to get behind the headlines and read the real story, click here:

http://esciencenews.com/articles/2008/05/13/metoprolol.around.time.surgery.increases.risk.death.and.stroke.poise.trial

http://www.nhs.uk/news/2008/05May/Pages/Betablockersurgeryrisk.aspx

http://www.sciencedaily.com/releases/2008/10/081020171233.htm

Image of β-blockers is provided courtesy of http://www.heartconsult.com

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