Fresh evidence in stent debate

Peter W. Groeneveld of Penn Medicine

Photo credit: Candace diCarlo

Approximately 10 million Americans have received drug-coated coronary stents since the devices were introduced several years back. But even though numerous clinical studies have been conducted on the stents since, the medical community has struggled to determine whether these drug-coated stents are any more effective than the more traditional, and cheaper, bare-metal stents.

If a new study from Penn researcher Peter W. Groeneveld is any indication, however, that debate may soon be settled.

Groeneveld, an assistant professor in Penn’s Division of General Internal Medicine, recently used Medicare data to survey the cases of 72,000 patients treated with drug-eluting stents in 2003. Then, by comparing the long-term health results of those patients against a control group who received bare-metal stents, Groeneveld and his team were able to show a “clear survival benefit” to the drug-coated stents.

In fact, the team reports that they saw a statistically relevant benefit to the drug-coated stents at 90 days, one year and two years after implantation. Their results were published in the May 27 edition of the Journal of the American College of Cardiology.

“There have been questions as to how effective [the drug-coated stents] really are as opposed to the old technology,” Groeneveld says. “There’s still a lot of controversy about which ones to use. Basically the drug-eluting stents have been on the market for only five years, and the outcome data as far as clinical use is only starting to roll in now.”

By putting that data to use, Groeneveld was able to take a much more broad, sweeping view of the stent controversy than those who have conducted more focused, and much smaller, clinical studies. The breadth of information included in this study, Groeneveld says, is what makes it so important to the debate.

“I had 150,000 patients in my cohort, as opposed to what would be considered a large clinical trial of maybe 800 patients,” he says. “Even if you were to combine a bunch of clinical trials, you might have a couple thousand. But we were able to take a look at issues such as mortality … and we were able to find that there is a statistically major difference [between the drug-coated stents and bare-metal stents].”

Groeneveld points out he isn’t questioning the importance of randomized clinical studies. He simply believes his study provides context that those studies can’t.

“There are things you just can’t learn in randomized clinical trials—such as what happens to patients who aren’t in randomized trials,” he says. “On one hand, you can say the patients [in my study] weren’t randomized. That’s true, they weren’t. But that’s the nature of observational research. You observe. You don’t control. ... You can always say that we didn’t control for something, but at the same time, this is a fairly big effect [we found]. It’s not subtle.”

Groeneveld’s work didn’t end there.

In a related study, he has shown drug-coated stents are also more cost-efficient than bare-metal stents. In that study, set to be published in the June edition of the American Heart Journal, Groeneveld reports that while drug-coated stents cost more than traditional stents, the drug-coated stents were more reliable in the first year after being implanted.

Groeneveld and his colleagues said they found patients who received drug-coated stents ended up needing additional stents 12 percent of the time; those who received bare-metal stents needed additional stents 15 percent of the time. The team also found that patients who received bare-metal stents were twice as likely to need bypass surgery in the first year after getting their stents. All told, the team estimated that the use of drug-coated stents delivered an average savings of $1,350 per patient within the first year of implantation.

Of course, even with the publication of these studies, the stent debate is likely to continue. And Groeneveld figures to remain an important voice.
To follow up on his most recent work, Groeneveld says he hopes to soon gain access to additional Medicare data—data that may allow him to learn even more about how patients fare years after receiving stents.

“I am very eager to be able to look at these outcomes for three and four years later,” he says. “I’m just waiting for that data.”

Originally published on June 12, 2008