Continuous glucose monitoring
Data continue to accumulate that this form of glycemic self-monitoring is effective to reduce HbA1c levels and minimize hypoglycemia in both type 1 and type 2 diabetes. The most important change to the 2022 American Diabetes Association (ADA) standards of care is recognizing CGM as level A evidence for those receiving basal insulin without mealtime insulin.5 There are four CGMs on the market, but most of the market uses the Dexcom G6 or the Libre 2. Both of these devices will be updated within the next few months to newer generation sensors.
While there are similarities and differences between the two devices, by late 2022 and early 2023 changes to both will reduce the dissimilarities.
The next generation Libre (Libre 3) will be continuous, and “scanning” will no longer be required. For those unable to get insurance to cover CGM, the Libre will continue to be more affordable than the Dexcom. Alerts will be present on both, but the Dexcom G7 will be approved for both the arm and the abdomen. The Dexcom also can communicate with several automated insulin delivery systems and data can be shared real-time with family members.
For clinicians just starting patients on this technology, my suggestion is to focus on one system so both the provider and staff can become familiar with it. It is key to review downloaded glucose metrics, in addition to the “ambulatory glucose profile,” a graphic overview of daily glycemia where patterns can be identified. It is also helpful to ask for assistance from endocrinologists who have experience with CGMs, in addition to the representatives of the companies.
COVID-19 and new-onset diabetes
From the beginning of the COVID 19 pandemic in 2020, it was clear that stress hyperglycemia and glucose dysregulation was an important observation for those infected. What was not known at the time is that for some, the hyperglycemia continued, and permanent diabetes ensued.
In one study of over 2.7 million U.S. veterans, men infected with COVID-19, but not women, were at a higher risk of new incident diabetes at 120 days after infection compared to no infection (odds ratio for men = 2.56).6
Another literature review using meta-analyses and cross-sectional studies concluded new-onset diabetes following COVID-19 infection can have a varied phenotype, with no risk factors, presenting from diabetic ketoacidosis to milder forms of diabetes.7
The current thought is that COVID-19 binds to the ACE2 and TMPRSS2 receptors which appear to be located on the beta-cells in the islet, resulting in insulin deficiency, in addition to the insulin resistance that seems to persist after the acute infection. Much more needs to be learned about this, but clinicians need to appreciate this appears to be a new form of diabetes and optimal treatments are not yet clear.
Dr. Hirsch is an endocrinologist, professor of medicine, and diabetes treatment and teaching chair at the University of Washington, Seattle. He has received research grant support from Dexcom and Insulet and has provided consulting to Abbott, Roche, Lifescan, and GWave. You can contact him at imnews@mdedge.com.
References
1. American Diabetes Association Professional Practice Committee. Pharmacologic approaches to glycemic treatment: Standards of Medical Care in Diabetes-2022. Diabetes Care. 2022;45(Suppl 1):S125-S143.
2. Rosenstock J et al. Efficacy and safety of a novel GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1): A double-blind, randomised, phase 3 trial. Lancet. 2021;398:143-55.
3. Frias JP et al. Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes. N Engl J Med. 2021;385:503-15.
4. Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387:205-16.
5. American Diabetes Association Professional Practice Committee. Diabetes technology: Standards of Medical Care in Diabetes–2022. Diabetes Care. 2022;45(Suppl 1):S97-S112.
6. Wander PL et al. The incidence of diabetes in 2,777,768 veterans with and without recent SARS-CoV-2 infection. Diabetes Care 2022;45:782-8.
7. Joshi SC and Pozzilli P. COVID-19 induced diabetes: A novel presentation. Diabetes Res Clin Pract. 2022 Aug 6;191:110034.