Intermittent-scanned continuous glucose monitoring with low glucose alarms decreases hypoglycemia incidence in middle-aged adults with type 1 diabetes in real-life setting

Abstract

ObjectiveThere is limited real-life data demonstrating that hypo-/hyperglycemic alarms added to continuous glucose monitoring (CGM) improve metabolic control in adults with type 1 diabetes (T1D).We evaluated the usefulness of switching from a flash or intermittent-scanned continuous glucose monitoring (is-CGM) device without low or higher glucose alarms to a is-CGM device with alarms to prevent hypoglycemia in adults with T1D. MethodsIndividuals with T1D and fearful of hypoglycemia, prone to hypoglycemia unawareness, and/or experiencing severe hypoglycemia while using is-CGM Free Style Libre 1 (FSL1) were switched to FSL2 with individually-programmable low glucose alarms. The primary endpoint was the changes in % time below range (TBR%) <70 mg/dl [3.9 mmol/l] and <54 mg/dl [3.0 mmol/l] after 12 weeks on FSL2 compared with FSL1. Secondary endpoints were changes in % time in range (TIR% 70–180 mg/dl [3.9–10.0 mmol/l]), % time above range (TAR%) >180 [10.0 mmol/l], mean interstitial glucose, glycemic management indicator (GMI), interstitial glucose coefficient of variation (CV%), hemoglobin A1c, and sensor's scans/day. ResultsWe included 108 individuals (57.4 % men), aged 58.2 ± 17.3 [95 % CI: 55.0 to 61.5] years, with mean diabetes duration 25 ± 14.6 [95 % CI: 22.1 to 27.7] years. Among individuals, 40 (37.0 %) had hypoglycemia awareness with Clarke's score ≥4 and 19 (17.5 %) had a history of severe hypoglycemia. The median low glucose alarm threshold was 70 [IQR: 65–70] mg/dl (3.9 [IQR: 3.6–3.9] mmol/L). By comparison of first 12 weeks on FSL2 vs. last 12 weeks on FSL1, TBR% <70 mg/dl decreased from 4.5 ± 4.4 to 2.3 ± 2.8 % (p < 0.001), TBR% <54 mg/dl decreased from 1.4 ± 2.2 to 0.3 ± 0.9 % (p < 0.001). TIR% was not significantly different (51.5 ± 14.9 vs. 52.9 ± 16 % (p = 0.13)), nor was TAR% (43.8 ± 16.2 vs. 44.7 ± 16.5 % (p = 0.5)). CV% decreased from 39.4 ± 6.9 to 37.9 ± 6.1 % (p < 0.001). Those at risk for hypoglycemia (TBR >4 % and >1 %, respectively, at baseline) showed a significant decrease in the incidence of hypoglycemia <70 and <54 mg/dl (p < 0.0001). Patients' satisfaction with hypoglycemia alarms was high, since all individuals opted to pursue using individual alarm beyond the study period. ConclusionSwitching from FSL1 to FSL2 with low glucose alarms reduced the frequency of hypoglycemia in middle-age adults with T1D, particularly in those who were prone to hypoglycemia awareness or severe hypoglycemia.