An updated American Heart Association scientific statement on the role of obesity in cardiovascular disease provides the first new guidance in 15 years, drawing on evidence that’s emerged in that time to clarify the potential of newer drug therapies and interventions like bariatric surgery and lifestyle modifications to curtail cardiovascular disease risks.
Dr. Tiffany M. Powell-Wiley
“The timing of this information is important because the obesity epidemic contributes significantly to the global burden of cardiovascular disease and numerous chronic health conditions that also impact heart disease,” said Tiffany Powell-Wiley, MD, MPH, chair of the volunteer statement writing group.
“One of the big takeaways that I hope people get from the statement is really making it clear that obesity is a complex disease, and that it is multifactorial,” Dr. Powell-Wiley said in an interview. “There are not just biological reasons why individuals have obesity, but there are environmental, psychosocial, and really multilevel factors that contribute to the development and course of obesity.”
Most significantly, Dr. Powell-Wiley said, “we want to emphasize that we really want to have cardiologists think about and focus on abdominal obesity in particular.”
A metric for cardiovascular risk that seems to gain credibility in the statement is the relationship of waist circumference to height regardless of overall weight. “That is a very important finding that we can now really think of waist circumference as an important measure in our clinical practice,” said Dr. Powell-Wiley, chief of the Social Determinants of Obesity and Cardiovascular Risk Laboratory in the division of intramural research at the National Heart, Lung, and Blood Institute. “We want to get across to providers that this is something that should be measured and should be followed over time, based on data from the last 15 years that waist circumference and abdominal obesity are associated with higher cardiovascular risk regardless of body mass index.”
The statement provides potentially groundbreaking advice on atrial fibrillation as a consequence of weight, noted Dr. Powell-Wiley. “Up until recently, we haven’t really thought about weight management as a part of managing Afib [atrial fibrillation],” she said. “This statement highlights the need to think about weight management in addition to anticoagulation as part of the pieces for managing Afib.”
Evidence on interventions
The statement, published in Circulation, also dives into the evidence surrounding the varied interventions for managing weight.
American Heart Association
“The biggest area where there’s much more data is bariatric surgery,” said Dr. Powell-Wiley. “There’s clear evidence that bariatric surgery lowers cardio mortality and all-cause mortality for patients, but we’ve also seen data around lifestyle interventions, with the Look AHEAD trial, which showed that while there were improvements in CV [cardiovascular] risk factors, we didn’t see the reduction in CV mortality that we wanted to see.”
The statement noted that the Look AHEAD trial (for Action for Health in Diabetes) of people with type 2 diabetes failed to show a significant reduction in major adverse cardiac events or CV mortality after almost 10 years of an intensive weight-loss intervention. Dr. Powell-Wiley added that the result seemed to be related more to the lack of weight loss with lifestyle interventions when compared with bariatric surgery.
The statement also addressed the effectiveness of drug treatments for weight control in managing CV risk, and while the evidence supporting pharmacotherapy specifically for weight loss has been mixed, emerging treatments have shown promise, Dr. Powell-Wiley said. “I think we now have some bright spots with new therapies that have been developed for diabetes and heart failure, such as the SGLT2 inhibitors as well as the GLP-1 agonists, and how they can also appear to improve weight and likely will improve CV mortality in patients with obesity.”
The “obesity paradox,” which Dr. Powell-Wiley noted is “definitely a controversial topic,” is also addressed in the statement. “We try to explain what it is and what we know about it right now,” she said. “We know for instance that patients with obesity, particularly those who have class 1 obesity or patients who are overweight, seem to do better in the short term in relation to coronary artery disease and heart failure, but the reasons for that are not necessarily clear.”
The statement also provides evidence-based insights on the use of diagnostic tools, including stress echocardiography and cardiac MRI as well as coronary angiography, and the clinical significance of specific echocardiographic changes in obese patients.
The writing committee also identified areas that need future research. “It’s really important to emphasize what we learned about the complexity of obesity over this time period,” Dr. Powell-Wiley said. “But again, we don’t have all the answers; there’s a lot more work to be done to understand what type of lifestyle intervention might be most beneficial, especially with addressing abdominal obesity, and how these new therapeutics around heart failure and diabetes may be useful in patients with obesity.
Obesity in adolescents is another area that needs further research, Dr. Powell-Wiley said. “How do we prevent obesity in those populations when we know they’re at risk for so much as they get older? Once you have obesity it’s hard to change that trajectory.”
The scientific statement was prepared by the volunteer writing group on behalf of the AHA’s Council on Lifestyle and Cardiometabolic Health, the Council on Cardiovascular and Stroke Nursing, the Council on Clinical Cardiology, the Council on Epidemiology and Prevention, and the Stroke Council. Committee vice chair Paul Poirier, MD, PhD, reported financial relationships with Abbott, Amgen, AstraZeneca, Bausch Health, Bayer, Boehringer Ingelheim, Eli Lilly, Janssen, Novartis, Novo Nordisk, Sanofi, Servier, and HLS Therapeutics. One committee member disclosed a financial relationship with AstraZeneca. Dr. Powell-Wiley and the other committee members have no relationships to disclose.