Simon Murray, MD: Who Should Be Treating Patients with Diabetes?

In the last of our 3-part series examining the idea of a cardiometabolic subspecialty, Simon Murray, MD, offers his thoughts on who should be treating patients with type 2 diabetes.

From the desk of Simon Murray, MD:

“The art of medicine is keeping the patient amused while the disease runs its own course.”

If this quote, attributable to Voltaire, made you think of diabetes, you wouldn’t be wrong… until the last decade. Recently, new advances in diabetic medicines have improved the outcomes for people with diabetes, particularly those with cardiovascular disease.

Trends show declining mortality from diabetes with patients with cardiovascular disease in wealthy countries.1 SGLT2 inhibitors developed for type 2 diabetes have shown a cardioprotective effect due to reduction of plasma volume from continuous urine glucose excretion without activating renin-angiotensin system and sympathetic nervous system—recent trials demonstrate this improvement in heart failure risk is even seen in nondiabetic patients.

Due to previous failures among glucose-lowering medications, the US FDA mandated that new diabetes medications undergo trials for cardiac safety in 2008. The unexpected benefit of this was the discovery of several new diabetic medicines that worked by unique mechanisms other than simply lowering glucose levels. Traditional hypoglycemic drugs through various mechanisms of action lower blood glucose and effectively reduce microvascular target end-organ damage like retinopathy, nephropathy, and neuropathy. However, they do not improve macrovascular end organs like coronary arteries. Worse yet, some agents like thiazolidinediones increased the risk of congestive heart failure and myocardial infarction.

A pair of landmark trials, CANVAS and EMPA-REG outcome, both showed reductions in all-cause mortality, cardiac mortality, and admissions for congestive heart failure using SGLT2 inhibitors.2 The demonstrated benefit was independent of the favorable effect on serum glucose levels, and the low risk of hypoglycemia.

Glucagon-like peptide 1 (GLP-1) analogues are a class of injectable hypoglycemic drugs that activate the endogenous GLP-1 receptor. They promote glucose-dependent insulin release, inhibit glucagon secretion, and delay gastric emptying.3 The LEADER trial showed that liraglutide was superior to placebo in reducing the primary composite outcome of CV death, MI, and stroke (13% vs 14.9% in placebo; P=.01). The reduction in the primary endpoint was driven by significantly lower CV mortality (4.7% vs. 6%; P=.007). Moreover, liraglutide reduced all-cause mortality as well (8.2% vs. 9.6%; P=.02).4 SUSTAIN-6, also showed composite CV event reduction (6.6% vs 8.9%; P=.02) with semaglutide, which was driven by a significant reduction in strokes (1.6% vs. 2.7%; P=.04) rather than CV mortality or MI.5

Since most of the risk reduction is due to cardiac disease reduction, it raises the question: who should manage diabetes?

Several studies have shown that patients with diabetes fare better when treated by endocrinologists compared to primary care doctors. A retrospective, 4-year study was done comparing several measures of compliance with diabetes guidelines between primary care doctors and endocrinologists. In this study, the endocrinologists were better on every measure.6 That study came as no great surprise since endocrinologists are better trained to treat diabetes.

Changing views about diabetes have begun to shift the focus on diabetes care from merely controlling blood sugar to treating all the metabolic dysfunctions that accompany diabetes. The protein adipsin, which is produced in body fat, helps protect insulin-secreting cells called pancreatic beta cells from destruction in type 2 diabetes, according to a study by researchers at Weill Cornell Medicine and New York-Presbyterian. By targeting this protein, beta cell function could be preserved, and insulin would remain normal.

So, should diabetes be managed by cardiometabolic specialists?

In practice, most people with diabetes are treated by their primary care doctor either by default or with whom they have a long-term relationship. They are better able to spot status changes and keep better track of complications. Shouldn’t the internist oversee managing diabetes? The following medical axioms may shed some light on this mostly theoretical discussion.

  1. Good doctors treat people, not diseases. It makes the case that maybe we are all different and there is no right choice.
  2. Patients do better with physicians they know and trust and who make them comfortable. People with long term relationships with primary care doctors generally live longer.
  3. Until recently, the outcome in type 2 diabetes was dismal and many physicians, including some endocrinologists, didn’t want to treat diabetes. It is time-consuming and pays poorly. The outcome of people with type 1 diabetes changed dramatically in 1922 with the discovery of insulin but results for type 2 diabetes stagnated for decades. An endocrinologist told me the worst thing that happened to the treatment of Type 2 diabetics was insulin discovery. We thought insulin would solve all our problems, not realizing that T1D and T2D are completely different diseases and lowering blood glucose was not the only way to prevent complications. Four decades passed before new research into the pathophysiology of diabetes began. We now think of diabetes as a cardiometabolic syndrome, not just a blood sugar issue.
  4. There are 6400 endocrinologists in the US with 123 new graduates every year. The supply is shrinking. These doctors are the best trained to treat diabetes, but they can’t do it and some may not want to treat diabetes. The CDC reports there are 25 million Americans with diabetes in the US and 79 million more with prediabetes. Endocrinologists are the lowest paid of all Internists, and it is challenging to attract top American students.
  5. Cardiologists in the US are, generally, more interested in interventions than the prevention of cardiac disease. I know that comment may be unsettling to some, but, unfortunately, in my experience it is true. How will the cardiologist deal with a patient with urinary frequency, blurred vision, or unexplained weight loss? The answer is most likely that the patient will be referred to a urologist, an ophthalmologist, or a gastroenterologist, respectively, and all three of those conditions are common symptoms in diabetes.

The person most likely to see the big picture is the primary care doctor. People with diabetes get all kinds of odd symptoms, involving many organ systems. They are best managed by being seen by the same physician regularly with scheduled monitoring of the toenails, circulation in the feet, the urine albumin, the health of the retina, sexual functioning, body fat, mental status, blood pressure, lipoproteins, Adiponectin, TMAO, A1c, dietary habits, the 46 miles of nerves that feel like fire or being stung by a thousand bees when damaged, or the 6-8 meters of intestine that can be paralyzed by autonomic dysfunction. It’s a lot to remember and it takes regular follow-up—having the cooperation and trust of your patient will make this easier

Even asking which specialist should manage diabetes highlights the main problem facing people with chronic disease in our medical system. The question itself shows how little many physicians value collaboration and communication. Patients with diabetes ultimately see dozens of specialists who are slow to communicate their findings or quick to change medications and treatment plans, which fragments care and causes confusion. There has been a gradual deterioration in collegiality and respect between primary care and specialists. It is pervasive and real.

Many times, specialists communicate through a third party like a physician assistant or nurse practitioner because they are too busy to talk directly to the primary care doctor. There may not be any intentional disrespect, but I am offended when a doctor only speaks to me through a third party. If there were ever a disease that epitomized the need for all players to be on the same page, it’s diabetes. The patients do best with a primary care doctor for their quarterback who knows the game, understands the rules and cooperates, and communicates cohesively with his teammates of dieticians, nurse educators, psychologists, cardiologists, endocrinologists, and surgeons. No one can do it alone. Teamwork. That’s the way it works best.

There is one essential caveat. The primary care doctor must keep up with the quickly changing technology by reading, attending meetings, and asking questions. If the quarterback can’t call the right play at the right time, the game will indeed be lost. Diabetes is very patient and a rapacious predator that methodically destroys people’s lives right under the nose of the ill-informed physician; however, good his intentions.