Case for Continuous Glucose Monitoring in Youth-Onset Type 2 Diabetes

Continuous glucose monitoring (CGM) is well established in the management of type 1 diabetes (T1D), with studies showing improved glycemic control with the use of CGM in both children and adults with T1D.¹ A growing body of research is investigating the potential benefits of CGM for type 2 diabetes (T2D), and findings thus far have shown promise for its use in adults.

In a randomized controlled trial reported in 2012 in Diabetes Care, adult patients with T2D (n=100) who were not on prandial insulin were assigned to either intermittent real-time CGM or self-monitoring of blood glucose (SMBG) for a 12-week period.²

They were subsequently followed for 40 weeks. Diabetes care was delivered by each patient’s regular provider, with no involvement by the researchers.

The results revealed significant and sustained improvement in the mean unadjusted hemoglobin A1c (HbA1c) levels of the CGM group vs the SMBG group. At 12, 24, 38, and 52 weeks, levels had decreased by 1.0%, 1.2%, 0.8%, and 0.8%, respectively, in the CGM group, compared with 0.5%, 0.5%, 0.5%, and 0.2%, respectively, in the SMBG group (P =.04).

The researchers stated that CGM “provides important feedback about glycemic trends in response to meals, exercise, and insulin in [people with] type 1 [diabetes] and type 2 [diabetes] on prandial insulin with resultant improvement in overall glycemic control.” Various other studies have demonstrated HbA1c reductions ranging from 0.5% to 2.7% with the use of CGM.³

Based on such findings, professional organizations now encourage the use of CGM for people with T2D to guide clinicians in medication adjustment and as a research tool.^4,5 Although evidence supporting the benefits of CGM in adult patients with T2D continues to increase, data are scarce pertaining to the use of CGM in childhood-onset T2D, according to a review published in Current Diabetes Reports.³ This is an important gap, considering the increasing prevalence of childhood-onset T2D.

T2D is linked with numerous cardiovascular and metabolic complications in the pediatric population, along with higher rates of monotherapy failure and faster disease progression compared with adults.^6,7 These associations are “in no small part because those affected are predominantly from disadvantaged backgrounds with limited resources and socioeconomic challenges affecting their ability to manage their disease effectively,” wrote the review authors. “Furthermore, much remains unknown about the pathophysiology and natural history of youth-onset T2D. Ongoing studies are needed to determine which management strategies are optimal for preventing disease progression and complications.”

Studies using CGM in this group thus far have focused on CGM as a research tool — for example, to identify links between glucose patterns and diabetes risk — rather than for personal use by adolescents. The authors note that although this population may be likely to have low adherence rates to personal use of CGM, the professional use of CGM could offer providers a more comprehensive understanding of a patient’s glycemic patterns.

In a cohort study of 98 obese children and adolescents with or without prediabetes, even patients with normal HbA1c, fasting plasma glucose, and 2-hour oral glucose tolerance test were found to have higher levels of free-living glucose on CGM than previously observed in non-obese children and adolescents.⁸ The findings further showed that HbA1c and oral glucose tolerance test were associated with differing glycemic patterns.

“Given the greater burden of disease in youth with T2D, further studies are required to identify whether or not intermittent use of CGM directed by a healthcare provider may lead to glycemic improvements and how best to use the device” to guide treatment in this population, the review authors concluded.

To further explore the use of CGM in children and adolescents with T2D, Endocrinology Advisor spoke with Harvey K. Chiu, MD, a pediatric endocrinologist at UCLA Health.

Endocrinology Advisor: What are some of the potential benefits of using CGM in children and adolescents with T2D?

Dr Chiu: As is well recognized, adolescents are notorious for often being suboptimal in terms of checking their blood glucose levels, and CGM, to a degree, may allow a more passive means of collecting that glucose data that may be helpful for our population on an aggressive insulin regimen. CGM may be enlightening for our patients and families who believe that if they do not see a high blood glucose, often because they are not checking, then there is not a problem — akin to the ostrich putting its head in the sand.

CGM may also be able to provide forewarning of an impending low blood glucose — more of a problem with T1D, but always a potential in a patient with T2D on an aggressive insulin regimen with strenuous exercise, illness, or other potential concurrent factor.

Endocrinology Advisor: What role do you envision for the clinical use of CGM in pediatric patients?

Dr Chiu: As we incorporate more regimens used in the adult population with diabetes into the pediatric population with diabetes, CGM may offer insight into the times of glucose fluctuation and help us tailor our medical regimen accordingly. For example, with greater mealtime excursions, we may increase mealtime insulin dosing, or perhaps use oral agents used in the adult population that are particularly effective toward targeting those mealtime glucose excursions. Research into this area is a wide open arena that we are only beginning to explore.

References

1. Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group; Beck RW, Hirsch IB, Laffel L, et al. The effect of continuous glucose monitoring in well-controlled type 1 diabetes. Diabetes Care. 2009;32:1378-1383.
2. Vigersky RA, Fonda SJ, Chellappa M, Walker MS, Ehrhardt NM. Short-and long-term effects of real-time continuous glucose monitoring in patients with type 2 diabetes. Diabetes Care. 2012;35:32-38.
3. Chan CL. Use of continuous glucose monitoring in youth-onset type 2 diabetes. Curr Diab Rep. 2017;17:66.
4. Peters AL, Ahmann AJ, Battelino T, et al. Diabetes technology—continuous subcutaneous insulin infusion therapy and continuous glucose monitoring in adults: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2016;101:3922-3937.
5. Fonseca VA, Grunberger G, Anhalt H, et al; Consensus Conference Writing Committee. Continuous glucose monitoring: a consensus conference of the American Association of Clinical Endocrinologists and American College of Endocrinology. Endocr Pract. 2016;22:1008-1021.
6. D’Adamo E, Caprio S. Type 2 diabetes in youth: epidemiology and pathophysiology. Diabetes Care. 2011;34(Suppl 2):S161-S165.
7. Today Study Group; Zeitler P, Hirst K, Pyle L, et al. A clinical trial to maintain glycemic control in youth with type 2 diabetes. N Engl J Med. 2012;366:2247-2256.
8. Chan CL, Pyle L, Newnes L, Nadeau KJ, Zeitler PS, Kelsey MM. Continuous glucose monitoring and its relationship to hemoglobin A1c and oral glucose tolerance testing in obese and prediabetic youth. J Clin Endocrinol Metab. 2015; 100:902-910.