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No evidence of obesity paradox after drug-eluting stent placement

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – Data from the German drug-eluting stent (DES.DE) Registry provide no evidence of the “obesity paradox” in the setting of percutaneous coronary intervention (PCI) and DES placement, researchers say.

Although overweight and obesity have traditionally been viewed as independent markers for coronary events, several recent studies have described an “obesity paradox” in patients undergoing PCI with bare-metal stents. These studies have reported similar or lower postoperative mortality in obese patients compared with normal weight patients.

“We think this is conceptually wrong and used the platform of the German DES Registry to show that the so called obesity paradox is not real (in modern interventional cardiology) and should probably be buried,” Dr. Christoph A. Nienaber from the Heart Center Rostock told Reuters Health by email.

In a report this month in JACC: Cardiovascular Interventions, the researchers report a comparison of clinical outcomes after PCI with DES implantation in 1,436 normal weight, 2,839 overweight, and 1,531 obese patients treated at 98 sites between 2005 and 2006.

At one-year follow-up, the three weight groups showed similar rates of all-cause death (3.3% vs. 2.4% vs. 2.4%, respectively; p=0.17), major adverse cardiac and cerebrovascular events (MACCE; 7.1% vs. 5.6% vs. 5.5%; p=0.09), and target vessel revascularization (TVR; 10.9% vs. 11.7% vs. 11.6%; p =0.56). There were also no differences in rates of myocardial infarction, stroke and stent thrombosis.

These similarities persisted after risk-adjustment for heterogeneous baseline characteristics of groups and were independent of the types of DES employed, the researchers note.

“The take home message is in brief that fatter is by no means better and any speculation on the so called obesity paradox should be left behind,” Dr. Nienaber told Reuters Health.

In their report, the researchers say the obesity paradox “may actually be a misnomer, or may not exist at all. Overweight and obese patients,” they point out, “are usually younger, with larger culprit vessel diameter than normal weight counterparts; their comorbidity index is usually higher without any differences in the extent of coronary artery disease.”

“Moreover, it is well established that younger patients have better clinical outcomes after acute MI regardless of reperfusion modality. Additionally, the presence of comorbidities in obese and overweight patients usually led to more aggressive therapy of cardiovascular risk factors likely to improve outcomes despite obesity,” the researchers write.

They acknowledge that their study suffers from the inherent limitation of an observational study and that potentially confounding factors such as physical inactivity, unintended weight loss, and socioeconomic factors were not analyzed and may have influenced the results. They also didn’t have data on waist circumference and waist-to-hip ratio.

“Prospective studies with long-term follow-up designed to confirm or refute the obesity paradox in the context of DES are required, focusing on fat distribution, central adiposity, temporal weight loss, and weight change,” the researchers conclude.


No Evidence of “Obesity Paradox” After Treatment With Drug-Eluting Stents in a Routine Clinical Practice

Journal of the American College of Cardiology: Cardiovascular Interventions, 2012;5:162-169.