Obesity and CVD: New Review Highlights Where Tools and Meds Fall Short

The number of people with a double diagnosis of obesity and cardiovascular disease is on the rise, making it imperative that cardiologists are aware that the tried-and-true diagnostic and therapeutic tools they typically rely on may have important limitations in patients with obesity, according to the authors of a new review.

“As cardiologists, we see a number of challenges that our cardiac patients with obesity face as we try to treat their heart conditions, but also some challenges with cardiac conditions in patients with obesity when they try to lose weight,” senior author Francisco Lopez-Jimenez, MD (Mayo Clinic, Rochester, MN) told TCTMD. “It works both ways. The presence of one makes the treatment of the other more difficult, and vice versa.”

According to a recent Centers for Disease Control and Prevention snapshot, nearly 42% of Americans are obese, up from 30.5% two decades ago. In his practice, Lopez-Jimenez estimates that roughly half of his patients are obese, a proportion that would likely be even higher for cardiologists practicing in states with a higher obesity prevalence.

Twenty-five years ago, “obesity wasn't really in the mind of clinicians as a medical problem,” he said. The first US guidelines for identifying and managing obesity were published in 1998, but it took decades for cardiology journals to start publishing research on the topic, he said. Even then, many seemed to do so reluctantly, reflecting a broader resistance in cardiology to acknowledge the interplay between the two conditions. Earlier work by Lopez-Jimenez and colleagues, for example, revealed that among patients with body mass index (BMI) over 35 who’d suffered a myocardial infarction, obesity wasn’t mentioned anywhere in their medical record as a potential contributing or complicating factor in their MI.

By publishing a state-of-the-art review of obesity in a cardiology journal, the authors, led by Rosana Bianchettin, MD (Mayo Clinic), hoped in part to remind physicians that there are treatments available today for helping their patients lose weight, but also sought to make them aware of the many ways that their standard approaches to diagnosis and care may need to be altered in this complex and growing patient population.

The review was published online January 31, 2023, in the Journal of the American College of Cardiology.

Tests and Treatments

The paper opens with a comprehensive review of common diagnostic tests in CVD and the challenges posed in an obese patient. “For many, many cardiology tests—electrocardiograms, echocardiograms, CT, MRIs, nuclear scans—the accuracy is not as good as it is in patients without obesity,” Lopez-Jimenez said. “And the more obese the patient is, many times the less accurate the test is, and that's important to keep in mind as we see patients with significant obesity and cardiovascular conditions, because we might think that the patient is ‘normal’ according to this or that but might be very abnormal. It’s just that the test cannot capture that.”

A second section summarizes the therapeutic challenges in people with a dual diagnosis of CVD and obesity. “One of the things that we really emphasize in the paper is that a lot of the guidelines for management and diagnosis in cardiology have not necessarily clarified the unique circumstances that relate to patients with obesity in terms of whether [a given] treatment is effective in patients with obesity, particularly more serious, medically complicated obesity than in others,” Lopez-Jimenez said. “Some treatments actually might not be very effective in patients with obesity, whereas other treatments might even become dangerous because patients with obesity might not metabolize those medications as well as patients without obesity.”

The more obese the patient is, many times the less accurate the test is. Francisco Lopez-Jimenez

Additional sections of the paper delve into the so-called obesity paradox (concluding that obesity does not directly protect against death in certain cardiovascular diseases) as well as the challenges and opportunities in CVD diagnosis in patients with high BMI.

One key takeaway should be that in patients with the double diagnosis of obesity and cardiac conditions, it is particularly challenging to lose weight, Lopez-Jimenez noted. “For example, a patient with heart failure has many dietary restrictions and also gets winded as soon as he or she starts walking around. This person will have a hard time exercising or sticking to an exercise program. . . . There are also some medications, like beta-blockers, that can actually make the patient gain weight or make it more difficult to lose weight. And yet we typically use those medications in many patients with heart disease.”

Other common advice may also prove problematic, he continued. Patients are always urged to stop smoking, particularly after a cardiovascular disease diagnosis, but “when people stop smoking, they generally gain weight or certainly have a very hard time losing weight,” he noted.

Humility and Hope

Historically, noted Lopez-Jimenez, obesity has made many physicians uncomfortable: they’re not sure how or when to address it, or they feel there’s little hope they can convince a patient to lose weight.

“I think it matters how we define success,” he said. “If the definition of success is taking a patient who weighs 300 pounds and bringing that patient down to a normal BMI, which might be, for that person, 160 pounds . . . it would be very hard to be successful in that regard. But if we consider that 10 pounds or even a 5% weight loss makes a huge difference in terms of health and outcomes, then that’s a different thing and there are different chances of success.”

Many cardiologists may need to rethink some of their preconceived notions around obesity treatments, most notably bariatric surgery, which has proven effective for weight-loss but which Lopez-Jimenez believes is underused. They could also be more aggressive about prescribing weight-loss drugs. He is particularly optimistic about the use of GLP-1 inhibitors for obesity, even in patients without diabetes.

Cardiologists and other caregivers need to also consider obesity as a lifelong disease requiring lifelong care. “We claim that obesity is not treatable because as soon as you stop the intervention, whether it is diet or medication, the patient regains the weight, but isn't that the case for blood pressure or diabetes, too? Chronic problems many times require chronic treatments,” Lopez-Jimenez observed.

He’s hopeful that cardiologists will increasingly embrace obesity as part of their scope of care and do more to help their patients lose weight, with an eye to the unique ways in which this impacts a patient’s cardiovascular needs. Also, he’s optimistic they’ll invest time and energy into learning more.

“For medicine to advance, we need to humbly recognize our limitations,” Lopez-Jimenez said. “I don't think that we have really accepted and recognized that when it comes to obesity, we don't really understand the underpinning of the physiopathology of obesity very well because if we did, we would have the cure already, or we’d have more solutions for the population in general.”