Take Diabetes to Heart: New Subspecialty of Cardiometabolic Medicine?

Miriam E. Tucker

August 05, 2019

The epidemic of obesity, cardiovascular disease, and type 2 diabetes has prompted a call for a new internal medicine subspecialty: cardiometabolic medicine.

As proposed, the field would include elements of endocrinology, cardiology, and primary care and would address the needs of a large patient population that is now being seen by multiple specialists.

"Yet to be clarified is who becomes the physician of record when patients who are obese, have type 2 diabetes mellitus treated with metformin, and glycosylated hemoglobin of 8.2% are hospitalized for acute coronary syndrome," say endocrinologist Robert H. Eckel, MD, of the University of Denver, in Colorado, and preventive cardiologist Michael J. Blaha, MD, of Johns Hopkins University, Baltimore, Maryland, in a commentary published online earlier this year in the American Journal of Medicine.

The recent availability of glucose-lowering drugs that have additional benefits has blurred the lines between specialties. Glucagonlike peptide–1 receptor agonists provide both cardiovascular and weight-loss benefits, and the sodium-glucose cotransporter–2 inhibitors reduce both rates of heart failure and cardiovascular mortality.

"Although the mechanisms for these cardiovascular benefits remain unclear, they extend well beyond glycemic lowering, and therefore are probably best considered diverse 'cardiometabolic' pharmaceuticals rather than simply type 2 diabetes drugs," Eckel and Blaha write.

In an interview with Medscape Medical News, Eckel commented, "This is an area that's gaining some momentum. I think it's very much needed.... We're thinking of something very formalized in terms of taking care of these patients, not just a certificate training program. I think it's going to be healthcare saving, because these patients aren't going to be juggled back and forth between their internist, their endocrinologist, and their cardiologist. I think this is the subspecialty we need."

He acknowledged that "this is not a quick fix. It will take a decade or two to develop, because we have to develop training programs and define the curriculum."

Need Is Clear, but Is Subspecialty the Right Solution?

Indeed, Furman S. McDonald, MD, senior vice president for academic and medical affairs for the American Board of Internal Medicine (ABIM), told Medscape Medical News, "I don't argue at all the importance that obesity, diabetes, and cardiovascular disease are linked and that treating those well is important, and the science is advancing on how to treat them. That would be impossible to argue against.

"But the theoretical demand alone is not enough to be recognized as a subspecialty. There are a coalescence of factors that go into it," he emphasized.

McDonald said that in general, "The special expertise precedes the attestation and certification. The discipline grows first, and the doctors then need to distinguish their expertise that they have developed from that of others."

Nathan D. Wong, PhD, professor and director of the Heart Disease Prevention Program in the Division of Cardiology at the University of California, Irvine, told Medscape that he "applauds the authors for a well-thought out proposal for a new subspecialty."

However, he also believes that "cardiometabolic" medicine "bears some similarities" to the also-proposed subspecialty of preventive cardiology.

"I completely agree that care of these patients with cardiometabolic risk is inadequate at present and not sufficiently addressed by endocrinologists or cardiologists.

"But I think it will be important to sort out how such a specialty might be distinguished from preventive cardiology and whether the latter should be a subspecialty of cardiology only, requiring one to have already completed a 3-year cardiology fellowship," he said.

The "Cardiometabolic Medicine" Proposal

As outlined by Eckel and Blaha, the specialized training would begin with 2 to 3 years of focused general internal medicine house-staff training, followed by 3 years of training involving selected elements of endocrinology and cardiology.

The endocrine side would include extensive training in the management of obesity, metabolic syndrome, type 1 and type 2 diabetes, lipid/lipoprotein disorders, hypertension, and lifestyle.

It would not include other areas of endocrinology, such as disorders of the thyroid, the hypothalamic-pituitary-adrenal axis, reproductive endocrinology, or metabolic bone disease.

The cardiology component would focus on primary and secondary prevention of atherosclerotic cardiovascular disease, electrocardiogram and echocardiography interpretation, coronary CT interpretation, stress testing, and inpatient cardiology consults.

It would omit training in critical care medicine, interventional cardiology, electrophysiology, advanced heart failure, and cardiac transplant.

In addition, "a substantial component of cardiometabolic medicine training would be advanced concepts in lifestyle" that would "go far beyond inquiring about diet, exercise, tobacco, alcohol, and illicit drug use," according to Eckel and Blaha.

"The cardiometabolic physician would gain expertise in smoking cessation including cessation pharmacology, novel tobacco products, advanced concepts in nutrition and diet, and use of mobile health technology to promote general physical activity and individualized exercise goals," they write.

The lifestyle component is extremely important, Wong said. "People going into a cardiometabolic or preventive cardiology specialty would need to obtain substantial training in lifestyle medicine as part of the curriculum, much more than is offered in current endocrinology or cardiology training. No physician subspecialty has adequate training in lifestyle medicine."

Wong also believes that because practitioners of family medicine care for a significant proportion of patients who have cardiometabolic disorders, they should also be eligible for the proposed "cardiometabolic" subspecialty, rather than limiting the subspecialty to those with general internal medicine training, as Eckel and Blaha have proposed.

What Does It Take to Become an Internal Medicine Subspecialty?

The ABIM currently certifies 20 official subspecialties of internal medicine, as well as a "focused practice in hospital medicine maintenance of certification program."

The most recent one to be recognized was adult congenital heart disease, in 2015.

Since 2006, the ABIM has followed criteria established in the Final Report of the Committee on Recognizing New and Emerging Disciplines in Internal Medicine – 2 for assessing whether a proposed subspecialty should be granted certification.

According to that document, the candidate discipline must

  1. Have a unique body of knowledge that cannot be fully incorporated into the parent discipline;

  2. Have clinical applicability to be practiced in a form that is distinct from the parent discipline;

  3. Contribute to the scholarly generation of new information and advance research in the field;

  4. Have an important social need, with evidence that its practice improves patient care;

  5. Require supervision and direct observation provided in formal training settings in order to achieve competence in the scope of practice;

  6. Have a minimum 12-month training period for demonstration of competence needed for certification;

  7. Commonly involve complex technology or specific site-of-care opportunities for learning that are best provided in the training setting;

  8. Have a positive value of certification that outweighs any negative impact on the practice of general internal medicine or an existing subspecialty or on the basic education in the core competencies of internal medicine.

"I always point people to the criteria," McDonald said. "I think there's pretty sound rationale behind them. If you take any of the current subspecialties, it's easy to see how they all fulfil these criteria.

"If something can't fulfil them, it's not quite ready."

Regarding item 5, McDonald noted that when a discipline is first formed, there's a period of about 6 years during which the individual clinicians who created it can become certified without a training period. After that, they need formal training by a program accredited by the Accreditation Council for Graduate Medical Education.

Typically, he said, organizations and societies develop around the topic and develop the training for unaccredited fellowships initially.

"Fellowships, journals, papers, advancing science...those help make the case for certification.... The expertise develops before the certification recognizes the expertise, not the other way around," he said.

Sleep medicine, established in 2007, and hospice/palliative medicine, established in 2008, are examples that evolved this way.

"Long before the ABIM discipline, the American Academy of Sleep Medicine had credentials," McDonald notes.

Another subspecialty, geriatric medicine, may also serve as a model for cardiometabolic medicine in that it was cosponsored in 1988 by the ABIM and the American Board of Family Medicine, so that a clinician could start from either of those disciplines.

McDonald explained, "If enough doctors start practicing cardiometabolic medicine...and they meet the criteria and make the proposal, then it could happen."

Eckel and Blaha believe now is the time for what they propose.

"The cardiometabolic medicine physician would be a new type of board-certified specialist poised to address issues related to the major global health problem of the 21st century," they conclude.

Eckel has received funding from the National Institutes of Health (NIH) and Endece and has served on scientific advisory boards for Merck, Sanofi/Regeneron, Novo Nordisk, and Kowa. Blaha has received funding from the NIH, the US Food and Drug Administraiton, the American Heart Association, Amgen, and Aetna and has served on scientific advisory boards of Amgen, Sanofi/Regeneron, Medicure, Novartis, and Novo Nordisk. McDonald has received compensation as an author from the Mayo Clinic Scientific Press, which was paid to Mayo International Health Program. Wong has received research grant support from Amgen, Boehringer-Ingelheim, Novo Nordisk, and Amarin and serves as a consultant for Amarin and AstraZeneca.

Am J Med. Published online March 11, 2019. Full text

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