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Saturday, June 11, 2005Widely used painkillers may carry a significant risk of heart attack, according to a British analysis that raises questions about the safety of ibuprofen and other drugs in its class. ....."We think that enough concerns exist to warrant a reconsideration of the cardiovascular safety of all NSAIDs," said Julia Hippisley-Cox, lead investigator of the British study and a professor of epidemiology at the University of Nottingham. Her analysis is reported Saturday in the British Medical Journal. According to the news account, here's what they found: Now, researchers in Britain have found a 24 percent increased risk for a first heart attack among people taking ibuprofen and a 55 percent elevated risk among those taking the prescription NSAID diclofenac. The research also confirmed earlier U.S. studies about the risks of COX-2 inhibitors, showing a 21 percent increased risk for a first heart attack among patients on Celebrex and a 32 percent increased risk for those taking Vioxx. Naproxen, an NSAID sold as Aleve, showed a slight increase in heart-attack risk, but the data was not clinically significant, researchers said. But the study's real numbers aren't nearly as dramatic. It was one of the studies that takes a group of people with a disease, in this case heart attacks, and compares them to a comparable group of people without the disease then combs through their histories to find what about the two groups is different. The assumption - and the key word is assumption - is that the differing characteristic is responsible for the disease. It is, as I've pointed out before in this space, a very flawed approach to determining cause and effect. And, once again, the researchers did a poor job of matching their cases and controls. Twenty-eight percent of the cases smoked compared to only 18% of the controls. Thirteen percent of the cases had diabetes compared to only 7% of the controls. Thirty-nine percent of the heart attack patients had high blood pressure, but only 30% of the controls did. Those four factors alone would explain the heart attacks, irrespective of the drugs they were taking. But, it's the drug use that's the most interesting - and the most damning. Of the heart attack patients, 21% took ibuprofen sometime within the three years preceding their heart attacks. For the control group, the figure was 18%, a difference of 3 percentage points. This is the basis of the claim that ibuprofen causes heart attacks. But a look at the other drugs used by the heart attack patients and the controls reveals just how shoddy the work on this paper - and its conclusions - are. We know that aspirin prevents heart attacks. And, we've seen abundant statistics backing up the claim that statins reduce the incidence of heart attacks, at least by a 3 to 5 percentage points. And yet, 36% of the heart attack patients took aspirin within the three year study period compared to only 20% of the controls. By the standards the authors used to condemn ibuprofen, it would seem aspirin is an even bigger risk. And statins? Nineteen percent of the heart attack patients took them compared to only 9% of the controls. They, too, would appear to be more of a risk than ibuprofen. There's no reason to think we've been wrong all these years about the data for aspirin and statins, but there's plenty of reason to think that this study is intrinsically flawed. posted by Sydney on 6/11/2005 03:31:00 PM 0 comments 0 Comments: |
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