AT ACC 15
SAN DIEGO (FRONTLINE MEDICAL NEWS) – Maintenance of long-term weight loss in obese or overweight individuals with atrial fibrillation was associated with nearly a sixfold greater likelihood of freedom from recurrent AF during nearly 5 years of active follow-up in the LEGACY study.
“The effect was dose dependent. The most important finding is that 46% of patients with at least a 10% weight loss were free from AF without the use of drugs or ablation procedures through nearly 5 years, versus 22% of those with 3%-9% weight loss, and just 13% with less than a 3% weight loss,” Dr. Rajeev K. Pathak said at the annual meeting of the American College of Cardiology.
LEGACY (Long-Term Effect of Goal-Directed Weight Management in an Atrial Fibrillation Cohort: A Long-Term Follow-Up Study) included 355 overweight or obese participants with paroxsymal or persistent AF who were offered the chance to participate in a dedicated weight-loss clinic. Regular participation in this clinic proved to be a key factor in losing weight, keeping it off, and reducing AF burden; the more frequently patients attended the quarterly sessions the better the outcomes, noted Dr. Pathak, a cardiologist and electrophysiology fellow at the University of Adelaide (Australia).
Of the 355 participants, 135 lost at least 10% of their body weight, 103 had a 3%-9% drop in body weight, and 117 had less than a 3% loss or a weight gain.
Year-by-year weight trends had a significant impact on outcome. The 141 patients with linear weight loss had a 76% AF-free rate with or without the use of drugs or ablation, compared with a 59% in the 179 patients with weight fluctuations and the 38% rate in those with no loss or a weight gain. Atrial fibrillation status was assessed by 7-day Holter monitoring at least annually.
Weight fluctuation – defined as a 1% or greater change in weight between two consecutive annual follow-ups – dampened the benefits conferred by weight loss. Patients who experienced more than a 5% weight fluctuation were 2.2-fold more likely to experience AF recurrence than were those without weight fluctuation.
Patients with a sustained 10% weight loss were 5.6-fold more likely to achieve long-term freedom from AF than were patients with lesser or no weight loss. The goal was 10% weight loss rather than a body mass index of 25 kg/m2 or less because once AF patients get down to a BMI below 27 kg/m2 the incremental benefit of each additional 1 BMI point in terms of freedom from AF becomes much smaller, said Dr. Pathak.
Weight loss also showed a dose-dependent effect on various cardiovascular risk factors. For example, mean systolic blood pressure fell by 18 mm Hg in subjects with at least a 10% weight loss, by 10 mm Hg with a 3%-9% loss, and by 7 mm Hg with a lesser weight loss. Triglycerides, LDL cholesterol, and glycemic control improved in similar fashion. In addition, weight loss showed beneficial effects on cardiac structure, with dose-dependent reductions in left atrial volume indexed for body surface area as well as interventricular septal thickness, Dr. Pathak continued.
He described the weight loss clinic as a “very simple” structured motivational and goal-directed program with face-to-face counseling.
“We have one patient, one physician, no props. We sit with the patient, discuss areas we can improve, then we devise a low-carb, low-fat, high-protein diet in consultation with the patient. Patients maintain a lifestyle journal where they log their meals and exercise. We prescribe at least 200 minutes of moderate-intensity activity per week. Eating is a behavioral pattern, and we have found this approach to be a very effective behavioral tool. Because the plan is developed in consultation with the patient, we’ve found patients tend to adhere to what they have planned,” he explained.
Discussant Dr. Bernard J. Gersh praised LEGACY as “a really wonderful study – very important.
“There are years of epidemiologic evidence suggesting that obesity contributes in a major way to the epidemic of atrial fibrillation, and you’ve taken it a step further,” added Dr. Gersh, professor of medicine at the Mayo Clinic in Rochester, Minn.
Playing devil’s advocate, he asked whether the observed reduction in AF might have nothing to do with weight loss, but could be explained simply by LEGACY perhaps having enrolled a highly compliant group of patients who agreed to attend a clinic and were more willing to take their medications.
Dr. Pathak rejected the compliance factor as an explanation for the results. He noted that while cardiovascular risk factors improved with greater weight loss, the need for antihypertensive, lipid-lowering, and antiarrhythmic medications decreased.
“The effect can’t possibly be due to increased compliance with medications, but rather it’s a true effect of the weight loss itself. So I think this is a true clinical effect and not an epiphenomenon,” he replied.
Dr. Pathak added that he and his coinvestigators are organizing a randomized controlled confirmatory study.
Dr. Prediman K. Shah , who chaired a press conference where the LEGACY study was highlighted, said the study provided him with one of the major take-home lessons from ACC 15.
“We can argue about the mechanism of atrial fibrillation till kingdom come, but the fact is that the association is very strong that weight loss is associated with a reduced burden of atrial fibrillation, and with a very robust magnitude of benefit. That’s one of the messages that I’ll take home with me from this meeting: The next time I see my fat patient with atrial fibrillation, I’m putting him on a weight-reducing diet as the first approach,” declared Dr. Shah, professor of medicine at UCLA and director of the Oppenheimer Atherosclerosis Research Center at Cedars-Sinai Medical Center in Los Angeles.
Dr. Pathak reported having no financial conflicts regarding this study, which was supported by university funds.
Simultaneously with Dr. Pathak’s presentation at ACC 15, the LEGACY study was published online ( J. Am. Coll. Cardiol. 2015 [doi: 10.1016/j.jacc.2015.03.002] )
