STEVE INSKEEP, HOST:
If you ever get surgery, you will want to know how effective the procedure is going to be. Is it going to fix your problem? And if it does, for how long? New research compares two medical procedures that are used to treat heart disease, and it finds a hidden element might explain why one procedure has better outcomes than the other. The hidden element is you and how you behave afterward. Let's figure this out with NPR's Shankar Vedantam, who comes by each week to share interesting social science research. Hi, Shankar.
SHANKAR VEDANTAM, BYLINE: Morning, Steve.
INSKEEP: OK, the procedures are what?
VEDANTAM: The two procedures are angioplasty and heart bypass surgery. They're very commonly used to treat blockages in the arteries in heart disease. In angioplasty, the artery is opened by inserting and inflating a balloon to push open the blockage. In bypass surgery, the patient's chest is opened and a new bypassed artery is built around the blocked artery.
INSKEEP: OK, so in both cases you're trying to get a clear path for blood, but one of them is way more invasive than the other.
VEDANTAM: That's right. Now patients getting bypass surgery tend typically to be sicker than the patients getting angioplasty. That's why the more invasive procedure is often recommended to them. But that leads us to a puzzle.
I spoke with Jason Hockenberry. He's a health policy expert at Emory University. He told me that once you get past the immediate complications of the surgery, the bypass patients tend to do better than the patients who get angioplasty. And this is puzzling because these were the patients who were the sicker ones to begin with.
JASON HOCKENBERRY: Traditionally, the physicians sort of attributed this to the mechanical advantage of bypass surgery, meaning that it was restoring blood flow more effectively than the angioplasty would.
VEDANTAM: Now, Hockenberry said, let me take a closer look at that. And what he and his colleagues have just done is they've done a massive analysis. And they think something else might be driving those different outcomes.
VEDANTAM: What they did was they linked survey data about people's behavior with Medicare data about whether they received one procedure or the other. And what they find is that patients who get the bypass surgery become far more likely to quit smoking than patients who get the angioplasty. There's also preliminary evidence that patients who get the bypass start exercising more - they get fitter - and that these changes might explain the differences in outcome.
Now, at the face of it, Steve, this is a real puzzle. And it doesn't make sense, because every patient who gets treated for heart disease today is told to quit smoking. So the question is why are some patients taking that message, you know, to heart?
INSKEEP: Get out of here. No, go on, go on. It's fine.
VEDANTAM: Well, let me have Hockenberry explain it to you.
HOCKENBERRY: What we hypothesized for this paper was that patients who received a more invasive treatment - meaning they got bypass surgery. Because of the nature of the surgery, they would have a big scar on their chest. It would be painful in the weeks immediately following to do something like to take a puff from a cigarette and that this would change their behavior differentially from those that received less invasive treatment.
INSKEEP: OK, so I suppose maybe the thing to do would be to do the angioplasty, which is less invasive, but also give people a scar?
VEDANTAM: Steve, I think that might be a very dangerous and risky smoking cessation program. And even if you say we should give people the bypass surgery because that'll get them to quit smoking, that has risks associated with it, because it's serious surgery. If Hockenberry's research is replicated, I think what this really suggests is we need more effective programs to get people to quit smoking, because that's where the real benefit might lay.
But at a broader level, I think this also points to the importance of integrating human behavior into studies of medical effectiveness. I mean, the underlying idea in the study has been replicated many times in other settings. When people pay more for a car, for example, they're more likely to take better care of it. So if you look only at breakdown statistics, you might say more expensive cars are always better than less expensive cars. But what we're missing is the human element, which is when you take better care of a car, it's going to last longer.
INSKEEP: Shankar, high-priced social science correspondent, we'll take good care of you.
VEDANTAM: (Laughter) Thank you, Steve.
INSKEEP: I'm glad you came by. That's NPR's Shankar Vedantam. You can follow him on Twitter at @HiddenBrain. You can follow this program at @MorningEdition and at @NPRinskeep. Transcript provided by NPR, Copyright NPR.