Benefits of a Switch from Intermittently Scanned Continuous Glucose Monitoring (isCGM) to Real-Time (rt) CGM in Diabetes Type 1 Suboptimal Controlled Patients in Real-Life: A One-Year Prospective Study §

Abstract

The switch from intermittently scanned continuous glucose monitoring (isCGM) to real-time (rt) CGM could improve glycemic management in suboptimal controlled type 1 diabetes patients, but long-term study is lacking. We evaluated retrospectively the ambulatory glucose profile (AGP) in such patients after switching from Free Style Libre 1 (FSL1) to Dexcom G4 (DG4) biosensors over 1 year. Patients (n = 21, 43 ± 15 years, BMI 25 ± 5, HbA1c 8.1 ± 1.0%) had severe hypoglycemia and/or HbA1c ≥ 8%. AGP metrics (time-in-range (TIR) 70–180 mg/dL, time-below-range (TBR) <70 mg/dL or <54 mg/dL, glucose coefficient of variation (%CV), time-above-range (TAR) >180 mg/dL or >250 mg/dL, glucose management indicator (GMI), average glucose) were collected the last 3 months of FSL1 use (M0) and of DG4 for 3, 6 (M6) and 12 (M12) months of use. Values were means ± standard deviation or medians [Q1;Q3]. At M12 versus M0, the higher TIR (50 ± 17 vs. 45 ± 16, p = 0.036), and lower TBR < 70 mg/dL (2.5 [1.6;5.5] vs. 7.0 [4.5;12.5], p = 0.0007), TBR < 54 mg/dL (0.7 [0.4;0.8] vs. 2.3 [0.8;7.0], p = 0.007) and %CV (39 ± 5 vs. 45 ± 8, p = 0.0009), evidenced a long-term effectiveness of the switch. Compared to M6, TBR < 70 mg/dL decreased, %CV remained stable, while the improvement on hyperglycemia exposure decreased (higher GMI, TAR and average glucose). This switch was a relevant therapeutic option, though a loss of benefit on hyperglycemia stressed the need for optimized management of threshold alarms. Nevertheless, few patients attained the recommended values for AGP metrics, and the reasons why some patients are “responders” vs. “non-responders” warrant to be investigated.

Comparison of the clinical effects of intermittently scanned and real‐time continuous glucose monitoring in children and adolescents with type 1 diabetes: A retrospective cohort study

“…Large glucose variability might increase oxidative stress and inflammation, which cause endothelial cell damage 25 and increase cardiovascular risk 26 . Several studies have shown that rtCGM is superior to isCGM in terms of reducing the TBR, and improving the TIR and HbA1c levels in adult patients with type 1 diabetes 7 , 8 , 9 , 10 , 11 . Reddy et al .…”

“… 7 and Préau et al . 10 reported that switching from isCGM to rtCGM reduced TBR and increased TIR in patients with type 1 diabetes, and suggested switching from isCGM to rtCGM as an alternative to changing the insulin delivery system in patients with suboptimal glycemic control. A 6‐month multicenter randomized controlled trial carried out by Visser et al .…”

“…CGM with isCGM using FreeStyle Libre, might show a higher frequency of TBR values than CGM with rtCGM using Dexcom G4, due to the difference in the accuracy of the two devices. Third, several reports have shown the hypo‐ and hyperglycemia alert systems and an alert system against excessive hypoglycemia available with rtCGM have beneficial effects 7 , 8 , 9 , 10 , 11 , 27 . In particular, the low‐glucose alert with rtCGM can greatly contribute to reducing TBR because patients can respond in a timely manner to hypoglycemia during exercise and in daily self‐management 9 , 10 , and during the night when they would otherwise be unaware of hypoglycemia 7 , 8 .…”

“…Several clinical studies have shown the superiority of isCGM and rtCGM to SMBG for glycemic outcomes and quality of life in patients with type 1 diabetes treated with multiple daily injections of insulin (MDI) or continuous insulin infusion 3 , 4 , 5 , 6 . In addition, some comparative studies have shown that rtCGM is better than isCGM at reducing hypoglycemia and improving glycemic control in adults with type 1 diabetes 7 , 8 , 9 , 10 , 11 .…”

Time in Range in Children with Type 1 Diabetes before and during a Diabetes Camp—A Ceiling Effect?

“…The ALERTT1 study showed that a switch from isCGM to rtCGM improved TIR in adults significantly after 6 months [ 9 ], while under sub-optimal control, such a switch leads to benefits in terms of hypoglycemia prevention but no significant reduction in hyperglycemia [ 10 ].…”