New insulin questioned; carbon emission price proposed

Readers address insulin dosing and propose going further on climate change.

Insulin clarified

I read with great interest the article “New insulins present benefits, challenges” in the July/August 2016 ACP Internist, which covered a talk at Internal Medicine Meeting 2016 given by Lillian Lien, MD, ACP Member. I would humbly challenge the statement that with Toujeo, higher concentration does not mean clinicians should lower the dose.

Photo by iStock
Photo by iStock

The article states, “Specifically, when switching to Toujeo from Lantus, use the same unit-for-unit dose.” In my own clinical practice, we have found profound hypoglycemia (as low as 20 mg/dL) with patients on Toujeo who have significant renal impairment when using the 1:1 dosing recommendation. Whether this is due to the effect of increased circulating insulin with reduced clearance or to some alternate mechanism remains to be explored and could potentially be the basis of further interesting research.

Anna Lim, MD, ACP Member
Fort Wayne, Ind.

Dr. Lien responds: I thank Dr. Lim for bringing up the important issue of managing patients with renal disease. I fully acknowledge her concern that insulin dosing in patients with renal disease must be done cautiously.

I can only speculate that the technical recommendation of using “1-to-1” or “unit-for-unit” conversion from older long-acting insulins to newer concentrated insulins assumes that the original dose of long-acting insulin was conservatively chosen in the first place. Unfortunately, there are many reasons why the original dose may be excessive, in which case a dose reduction is certainly appropriate when starting the newer insulins. For example:

  • Patients on twice-a-day, high doses of a long-acting insulin may in fact not have been entirely adherent to the twice-a-day dosing, so they may have actually been taking less than the reported daily dose.
  • Patients with advanced chronic kidney disease should generally be on less basal insulin than normal, i.e., even as little as 0.1 or 0.2 units/kg of basal insulin per day, depending on severity.

If the original insulin dose was possibly excessive, then there is no question that the new dose should be reduced for safety. Certainly, if Dr. Lim has experienced cases where the original basal insulin dose was as low as 0.1 or 0.2 units/kg per day and the switch to the newer concentrated insulins still led to hypoglycemia, then that is important anecdotal evidence for all of us to know. I suggest that we all continue to report our experiences and use particular caution in patients with renal disease.

Editor's note: Dr. Lien disclosed that she is a consultant for insulin manufacturers Sanofi-Aventis, Merck, Eli Lilly, and Novo Nordisk.

Climate change

We applaud ACP for its recent position paper on climate change and health (published online April 19 by Annals of Internal Medicine) and the cogent summary of the findings and recommendations provided by ACP President Nitin S. Damle, MD, MS, FACP, in the July/August 2016 ACP Internist (“Internal medicine can slow climate change, improve health”).

Photo by iStock
Photo by iStock

Both the paper and Dr. Damle's column provide excellent overviews and calls to action on the most existential issue of our lives. The College has provided a superb toolkit with talking points for physicians, a fact sheet for patients, and a PowerPoint presentation for us to educate each other and our communities, as well as recommendations and resources for greening our practices and institutions.

These efforts aimed at individual physicians and medical institutions are all necessary and laudable. By themselves, however, they are insufficient to combat the urgency and scale of the problem. They are like diet and exercise for severe uncontrolled diabetes, necessary but inadequate when what we need is a strong dose of insulin to drive down the glucose quickly. What we need next to combat climate change is a concerted national policy to rapidly drive down greenhouse gas emissions.

A nationwide price on carbon emissions is like insulin. Ninety percent of economists agree that carbon pricing is the best mitigation policy because it harnesses the entire economy, using market forces to rapidly reduce greenhouse gases. Although what to do with the money collected from the fees is a legitimate and important political question, the need for carbon pricing itself transcends politics. Given the overwhelming health impacts, physicians have a legitimate interest in discussing policy, just as they do for health insurance.

The most effective, equitable, cost-efficient, and transparent way to put a price on carbon, one that could actually gain the support of both progressives and conservatives, is a carbon fee and dividend. By putting a steadily increasing price on carbon emissions at the source and then returning all funds to each household, we can achieve the needed CO2 reductions while creating 2.8 million jobs and saving hundreds of thousands of lives here in United States, not to mention the millions of lives that would be saved worldwide. The medical community should use its substantial individual and joint influence to encourage Congress to pass a carbon fee and dividend measure as soon as possible.

Linda Karl, MD, ACP Member
Tucson, Ariz.
Cynthia Mahoney, MD
Contra Costa, Calif.

Editor's note: Drs. Karl and Mahoney write on behalf of the Tucson and Contra Costa Chapters of the Citizens' Climate Lobby.

Dr. Damle responds: I thank Drs. Karl and Mahoney for their thoughtful and intriguing idea of a carbon tax with dividend. Although ACP's position paper did not mention this specific mitigation effort, ACP does support exploring this measure along with others in our call to action on climate change and health. The benefits of health economics are an important factor in the movement toward clean energy. The health effects are real, and occurring as we speak. The health benefits of reductions in greenhouse gas emissions and air pollution will decrease the incidence of multiple health problems, from better respiratory health to food insecurity.