Vioxx, Celebrex, Naproxen, and Aspirin

[billroper]

I've tried some cursory web browsing to see if I can find an answer to this question and have failed utterly. So, absent data, I post speculation which is probably wrong, but which is an entertaining thought.

Recent studies have shown that taking Vioxx, Celebrex, or Naproxen tend to increase the user's risk of heart attack and stroke, according to press reports. This leads to the next question: "Relative to what?"

See, I recall research that indicates that taking aspirin will reduce your chance of heart attack and stroke. If you're among the experimental group in a study taking high doses of an anti-inflammatory, you're not likely ever to take any aspirin, because you're on enough similar pain medication to choke a horse.

But what about the control group? Did they take aspirin now and again? Is it possible that what this research has done is to measure not an increased risk of heart attack and stroke among the experimental group, but a decreased risk of heart attack and stroke in a control group that took the occasional aspirin?

This inquiring mind would like to know.

Comments

[tigertoy.livejournal.com]

In light of how much money the makers of the branded Cox-2 inhibitors stand to lose, you can be very sure they've looked over the studies very carefully to find any confounding factors. I think to make this theory stick, you would have to posit a conspiracy on the part of the control group, not just to use aspirin, but to lie by not reporting it to the people doing the study.

I heard something on the radio to the effect that science was aware that there was something about Cox-2 drugs that made platelets slightly stickier, tending to promote blood clots; however, before these studies there wasn't evidence that it was medically significant. So, given that there seems to be an actual mechanism, and that so many different studies have seen an effect, it's probably really there. The big question is how big the risk really is compared to the benefit -- and even if the benefit is worth the risk medically, whether the manufacturers will still sell the drugs in light of the potential financial liability.

[billroper]

I don't think there necessarily has to be a conspiracy. It may just be a question of how little aspirin you can take and have a therapeutic effect. And how well controlled the control group is, of course.

[huskiebear.livejournal.com]

Actually, most of the randomized trials were done against other antiinflammatories (scientists having *some* degree of pity for suffering patients), and the patients would be told to report any other meds they were using during the study. There is a known cardio-protective effect of Naproxen, but a meta-study of published trials and observational studies that just came out in the Lancet found the effect to be not statistically significant, and not large enough to explain the findings in the Vioxx study. So yes, They did think of that...


Disclaimer: I'm not a real doctor. I have a Master's Degree... in SCIENCE!

[billroper]

Scientists? Pity? :)

Seriously, thanks for the data from Lancet.

[tigertoy.livejournal.com]

Hey, most scientists aren't like Dermot.

[sdorn.livejournal.com]

It's a good question to ask—sometimes relative-risk estimates are in comparison to the total sample (more likely in economics) and sometimes to an omitted category (more likely in sociology, demography, and epidemiology).

huskiebear makes a good explanation of why it's the latter in medical studies. I'm not sure why there are different traditions in the social sciences.