Apples, oranges, and brightly colored machine tools
Clearly someone is looking out for me today. Here I am, getting my bad self bogged down in a high-flown assessment of the meaning of high health care costs in the U.S. – not my field, but who’s counting? – when a glance at the clock tells me it ain’t gonna happen. If I’m going to keep my promise to get something posted before a reasonable bedtime, I thought, best to shelve health care costs for now and find myself a nice, straightforward epidemiology target. And maybe mix a few metaphors while I’m at it.
And there it was in my news feeder, the first one on the list from the Center for the Advancement of Health: Fish Fatty Acids May Prevent More Sudden Deaths Than Defibrillators. And yes, it’s just as surreal as it sounds. (As in, “How many surrealists does it take to change a lightbulb? Answer: Two. One to hold the giraffe, and the other to fill a bathtub with brightly colored machine tools.”) To be fair to the CFAH writer, the news article is based on a soon-to-be-published article (October) in the American Journal of Preventive Medicine, by TE Kottke and colleagues, which I have not yet seen, so I am relying only on the news article.
OK. Without getting into the numbers, let’s just say they are estimates, not measurements on actual people. The population examined is a simulated population, because it is “difficult to compare their effectiveness across a [real] population.” But the respective effectiveness of omega 3’s and defibrillators at lowering cardiac death is known from research – albeit with some kind of range of uncertainty attached to each. That’s one thing I’d like to see acknowledged – is there some kind of lower and upper bound on the relative effectiveness of these two preventive agents? And where does that uncertainty come from? Yes, there are very good quality studies, such as intervention trials, showing that omega-3 fatty acids, those found in fish, lower heart disease risk, but the endpoint of cardiac death comes from somewhat lower-quality prospective cohort studies (with attendant uncertainty in dietary consumption estimates).
But really, my first thought when I read this article was, Show me the policy relevance of this article. Why are we comparing fatty acids in fish with defibrillators? Is there actually someone making a choice on behalf of a population between one and the other, some Wizard of Oz who gets to say, “Well, we do need to prevent cardiac deaths, but those defibrillators are too expensive and people aren’t trained to use them right; you shall eat salmon instead. I like salmon.”? In what universe? Or someone says, “I think I’m having a heart attack; someone give me an omega-3 supplement, quick!” Sorry, too late; we blew our defibrillator budget on canned fish, and a supplement is not going to help you at this point if you foolishly snuck all your tuna salad to the cat. I'm exaggerating a little here for effect; the authors did discuss an intervention of daily omega-3 supplements, not fish, but I think my point still holds. (Wait - do you think it makes a difference whether people eat fish or take supplements? Hmmm...)
Tomorrow I shall call the editorial office of the American Journal of Preventive Medicine and get a copy of the paper. If it clears up my confusion, I’ll let you know.
American Journal of Preventive Medicine
omega-3 fatty acids
sudden cardiac death