Obese, Overweight Fare Better Post-PCI Than Leaner Counterparts

Patrice Wendling

July 07, 2017

STOKE-ON-TRENT, UK — Obese and even overweight patients have better survival and fewer major adverse cardiovascular and bleeding events after PCI than their normal-weight or lean counterparts[1].

In addition, these benefits persist up to 5 years after PCI and were seen in both stable and more acute settings, new research suggests.

"There needs to be more work to look at why this is the case, but it's important for patients to adopt healthy lifestyles and certainly not to eat foods that are calorific to gain weight, because we know obesity is detrimental to their longer-term health outcomes," senior study author Dr Mamas A Mamas (Royal Stoke Hospital, University Hospital of North Midlands, Stoke-on-Trent, UK) told theheart.org|Medscape Cardiology.

The study, published in the July 10, 2017 issue of JACC: Cardiovascular Interventions, follows a new National Cardiovascular Data Registry analysis[2], in which older STEMI patients who were mildly obese were 30% more likely to survive and spent fewer days in the hospital than those of normal weight or who were extremely obese.

The so-called obesity paradox, or protective effect of being overweight, is so well supported by studies in cardiovascular diseases that researchers have previously suggested, "it isn't a paradox at all but should be moved to a paradigm," said Dr Laurence Sperling (Emory Heart Disease Prevention Center, Atlanta, GA), who was not involved with either study.

He said obese and overweight patients with CVD and other chronic diseases such as cancer may have greater reserves to be able to withstand the demands of a chronic condition. Another possibility is that physicians may catch obese patients "at a point in time when they appear metabolically healthy because their blood pressure is normal, their glucose is normal, various markers of health look good, but the majority are on their way to being metabolically unhealthy and obese."

The investigators, led by Dr Eric W Holroyd (Royal Stoke Hospital), examined the relationship between BMI and adverse outcomes in 345,192 participants in the British Cardiovascular Intervention Society registry who underwent PCI between 2005 and 2013. Based on BMI, 3007 were classified as underweight (BMI <18.5 kg/m2), 87,279 as normal weight (18.5–24.9 kg/m2), 146,517 as overweight (25–30 kg/m2), and 108,190 as obese (>30 kg/m2).

Obese patients were significantly younger than overweight, normal-weight, or underweight patients (62.4 vs 64.8 vs 67.1 vs 69.6 years) but were more likely than patients with normal BMIs to have features of the metabolic syndrome, including hypertension (62% vs 49%), hypercholesterolemia (61% vs 53%), and diabetes (29% vs 13%). Radial access was also more common in obese than normal-weight patients (48% vs 44%), although use of drug-eluting stents was similar.

Patients who were obese or overweight compared with normal-weight or underweight had lower unadjusted mortality at 30 days (1% vs 1% vs 2% vs 4%), 1 year (3% vs 4% vs 6% vs 14%), and 5 years (19% vs 20% vs 28% vs 53%; P<0.001 for all).

After adjustment for relevant covariates, mortality was significantly lower in patients with elevated BMIs up to 5 years post-PCI. Similar mortality advantages were seen in overweight patients when analyzed based on clinical presentation (stable angina, unstable angina or non-STEMI, and STEMI), by patient subgroups, and in inverse probability weighting by propensity-scores analysis.

Adjusted Odds (95% CI) of Adverse Outcomes by BMI Group

  <18.5 kg/m2 18.5–24.9 kg/m2 25–30 kg/m2 >30 kg/m2
30-d mortality 1.23 (0.98–1.54) 1.0 (reference) 0.86 (0.80–0.93) 0.90 (0.82–0.98)
1-y mortality 1.85 (1.63–2.10) 1.0 (reference) 0.70 (0.67–0.73) 0.73 (0.69–0.77)
5-y mortality 2.48 (2.16–2.85) 1.0 (reference) 0.78 (0.75–0.81) 0.88 (0.84–0.92)
MACE 1.02 (0.81–1.29) 1.0 (reference) 0.96 (0.90–1.02) 0.95 (0.89–1.02)
Major bleeding 1.24 (1.00–1.54) 1.0 (reference) 0.92 (0.86–0.97) 0.87 (0.81–0.93)

The reduction in in-hospital major bleeding in overweight and obese patients was likely driven in part by the higher rates of radial access. Also, a lack of appropriate weight-based anticoagulation dosing could have led to possible overdosing in patients with low BMIs, particularly in the acute setting, Mamas said.

"This leads to greater complications, and it's been consistently shown in the literature that low-weight patients are much more likely to have more bleeding complications probably related to anatomical reasons but also pharmacological reasons," he added.

The study's biggest limitation is that BMI is not a great measure of obesity, Mamas said. "For example, very muscular individuals can have an elevated BMI, and yet we wouldn't know whether the high-BMI cases here are just heavily muscular people or obese or overweight people."

Conversely, people could have had a relatively normal BMI but have quite significant central adiposity, and "waist-to-hip ratio is known to be a better marker of future cardiovascular risk than BMI."

Other limitations include the inability to capture recent weight loss and frailty as well as use of guideline-recommended medical therapy or postdischarge secondary-prevention therapies. Mamas observed that Australian researchers have shown that overweight and obese patients undergoing PCI are more likely to be prescribed secondary-prevention therapies, and "we know that aggressive medication is associated with better outcomes."

In an accompanying editorial[3], Drs Debabrata Mukherjee and Chandra Ojha (Texas Tech University, El Paso) agree that "BMI may not be the most accurate measure of adiposity" and point instead to the critical role cardiorespiratory and physical fitness play in the relationship between obesity and CVD outcomes.

They note, for example, that a recent study in men with known or suspected CVD[4] reported that cardiovascular fitness greatly modifies the relation of adiposity to outcomes, with a higher risk of all-cause mortality associated with low physical fitness across normal-weight and class I, II, and II obese individuals.

In a second study of patients with systolic heart failure[5], no obesity paradox was observed in those with high cardiorespiratory fitness.

"The editorial makes some important points about fatness and fitness and how that relationship is really important as we think about obesity in chronic disease states," Sperling said. "You are much better off being fatter and fitter than a skinny couch potato."

In the immediate PCI setting or even longitudinally following up, he said physicians may want to be less emphatic about the need for weight loss, but that the message needs to be individualized.

"You may have someone who's obese, has sleep apnea, and poorly controlled hypertension, and for those patients, modest weight loss might be indicated. I don't think you can give a blanket statement 'Don't worry about it,'   " he said.

"It's a complex message and some patients may embrace this and say it's okay to be fat," Sperling said. "The messaging should be fitness first, healthy dietary patterns as a supportive approach because we know a Mediterranean dietary pattern can reduce cardiovascular events by about 30%, and then working within a physician-patient partnership to talk about goals and objectives related to that patient's weight as it relates to their personal medical care."

The study was supported by the University Hospitals of North Midlands Charity. The authors have reported that they have no relevant financial relationships. Sperling, Mukherjee, and Ojha reported no relevant financial relationships.

Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org, follow us on Twitter and Facebook.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.