Effect of Prior Glucose Monitoring on Glycemic Outcomes With a Hybrid Closed-Loop System

Adolescents and adults with type 1 diabetes who both have and have no experience using a continuous glucose monitoring system (CGM) would benefit similarly from using the US Food and Drug Administration (FDA)-approved MiniMed™ 670G hybrid closed-loop (HCL) system therapy, according to a 3-month pivotal trial published in Diabetes Technology & Therapeutics.¹

To examine how prior CGM experience influences glycemic outcomes, researchers compared hemoglobin (Hb) A1c levels and the percentage of sensor glucose (SG) values in low (≤70 mg/dL), high (>180 mg/dL), and in-target (71-180 mg/dL) ranges in 78 patients with prior CGM experience with 46 patients with no prior CGM usage.¹ Compared with baseline values, the researchers found that HbA1c values in patients with prior CGM experience decreased from 7.4%±0.9% to 6.9%±0.7%, and for patients without prior CGM usage these values declined from 7.5%±0.9% to 6.8%±0.5%.

The mean percentage of in-target SG values increased from 66.9%±12.5% to 72.6%±9.1% in patients with prior CGM experience and from 66.6%±11.7% to 71.5%±8.5% in patients without prior CGM usage. Similar improvements in low and high SG values were observed for both groups.

A limitation of the study was that the duration of time for prior CGM usage was not collected from patients that reported having used a CGM system.¹ However, previous studies comparing sensor-augmented pump therapy or conventional insulin pump use with HCL or CL system use have also reported improved in-target SG values, SG variability, and HbA1c values.^2-7

The investigators concluded that, “The comparison of glycemic outcomes between participants with and without CGM experience, before entry into the Medtronic MiniMed 670G HCL system pivotal trial, showed no significant difference in HbA1c reduction or direction and magnitude of improved time in target glucose range, hypoglycemia and hyperglycemia levels.”¹

References

1. Cordero TL, Garg SK, Brazg R, et al. The effect of prior continuous glucose monitoring use on glycemic outcomes in the pivotal trial of the MiniMed™ 670G hybrid closed-loop system [published online November 17, 2017]. Diabetes Technol Ther. doi:10.1089/dia.2017.0208
2. Kovatchev B, Cheng P, Anderson SM, et al. Feasibility of long-term closed-loop control: A multicenter 6-month trial of 24/7 automated insulin delivery. Diabetes Technol Ther. 2017;19:18-24.
3. Leelarathna L, Dellweg S, Mader JK, et al.: Day and night home closed-loop insulin delivery in adults with type 1 diabetes: three-center randomized crossover study. Diabetes Care. 2014;37:1931-1937.
4. Bally L, Thabit H, Kojzar H, et al.: Day-and-night glycaemic control with closed-loop insulin delivery versus conventional insulin pump therapy in free-living adults with well controlled type 1 diabetes: An open-label, randomised, crossover study. Lancet Diabetes Endocrinol. 2017;5:261-270.
5. Tauschmann M, Allen JM, Wilinska ME, et al.: Day-and night hybrid closed-loop insulin delivery in adolescents with type 1 diabetes: A free-living, randomized clinical trial. Diabetes Care. 2016;39:1168-1174.
6. Thabit H, Tauschmann M, Allen JM, et al.: Home use of an artificial beta cell in type 1 diabetes. N Engl J Med. 2015;373:2129-2140.
7. Nimri R, Bratina N, Kordonouri O, et al.: MD-logic overnight type 1 diabetes control in home settings: a multicentre, multinational, single blind randomized trial. Diabetes Obes Metab. 2017;19:553-561.