Real-time continuous glucose monitoring or continuous subcutaneous insulin infusion, what goes first?: results of a pilot study

Dual devices allow both continuous subcutaneous insulin infusion (CSII) and real-time (RT) continuous glucose monitoring (CGM). Patients usually start with CSII, adding RT-CGM later (CGM post-CSII). Lack of use of RT-CGM is the main limiting factor of dual device results. Initiating RT-CGM before CSII (CGM pre-CSII) could increase RT-CGM frequency use and further improve glycemic control.

In this 26-week pilot study, we randomly assigned, via sealed envelopes, 16 CSII and RT-CGM to naive patients 14 years of age or older with type 1 diabetes mellitus (T1DM) to CGM post-CSII or CGM pre-CSII. The Paradigm® Veo™ (Medtronic Inc., Northridge, CA) was the dual device used in all patients. The primary end point was frequency of use of RT-CGM between both groups at week 26.

We detected a significant higher RT-CGM frequency use in the CGM pre-CSII group at week 26 (78.4±10.9% vs. 56.0±40.8%; P=0.01), although we did not detect hemoglobin A1c level differences. In addition, CGM pre-CSII patients presented less time in hypoglycemia (average daily area under curve <70 mg/dL per 24 h, 0.87±1.02 mg/dL/day vs. 3.32±2.19 mg/dL/day; P=0.021), and no severe hypoglycemia events were detected during 26 weeks in this group.

CGM pre-CSII is effective in increasing RT-CGM frequency use in T1DM patients. This is accompanied by a significant reduction in time in hypoglycemia.