Previous studies have found an association between lower BMI and increased mortality among patients receiving CRT, but the reasons behind this link are not clear.
Dr. John W. Rikard and colleagues of the Cleveland Clinic Foundation, in Ohio, evaluated whether the survival advantage associated with obesity was related to left ventricular remodeling and improved LVEF in their study of 206 patients with normal BMI, 297 overweight patients (BMI, 25 to <35 kg/m2), and 301 obese patients (BMI, 35 kg/m2 or higher).
The mean increase in LVEF following CRT implantation did not differ significantly among normal-weight patients (8.1%), overweight patients (8.8%) and obese patients (9.3%).
Although CRT response, defined as an improvement of at least six percentage points of LVEF post-CRT, was significantly more common in obese patients (53%) than in overweight (49%) or normal weight (41%) patients, response to CRT was not affected by BMI in a multivariable analysis.
During a mean follow-up of 7.1 years, event-free survival was significantly higher among obese patients (47%) than among overweight (34%) and normal weight (26%) patients.
In multivariable analysis, higher BMI independently predicted better event-free survival, the researchers report in Circulation: Heart Failure.
"This suggests that otherwise appropriate CRT placement should not be avoided on the basis of elevated body weight," the authors note. "Furthermore, CRT response alone does not completely account for the event-free survival noted in patients with obesity. Reasons for this remain unclear."
"Further study is needed to ascertain the mechanism of this observation," they add.
Dr. Gregg C. Fonarow of Ahmanson-UCLA Cardiomyopathy Center, in Los Angeles, recently evaluated the link between BMI and outcomes of CRT in older patients with heart failure. That study, he told Reuters Health by email, "involving over 18,000 patients with heart failure receiving CRT-D devices in the U.S., found that men and women who were overweight or obese by body-mass index had improved survival compared to those in the healthy-weight category."
The new study's "findings further reinforce that obesity does not limit response to heart failure devices, like cardiac resynchronization therapy," he said.
"This study also is consistent with the so-called obesity paradox, where obesity is a risk factor for developing heart failure, but for patients with established heart failure, obesity itself is not associated with excess risk for poor outcomes," Dr. Fonarow said.
"Further studies are needed to determine if intentional weight loss in obese patients with established heart failure can improve or perhaps worsen outcomes," he said.
Dr. Rikard did not respond to a request for comments.
By Will Boggs MD
SOURCE: https://bit.ly/2TF9DXk Circulation: Heart Failure, online October 15, 2020.
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