Comparison of the FreeStyle Libre Pro Flash Continuous Glucose Monitoring (CGM) System and Point-of-Care Capillary Glucose Testing in Hospitalized Patients With Type 2 Diabetes Treated With Basal-Bolus Insulin Regimen

Abstract

OBJECTIVE We compared the performance of the FreeStyle Libre Pro continuous glucose monitoring (CGM) and point-of-care capillary glucose testing (POC) among insulin-treated hospitalized patients with type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS This was a prospective study in adult patients with T2D admitted to general medicine and surgery wards. Patients were monitored with POC before meals and bedtime and with CGM during the hospital stay. Study end points included differences between POC and CGM in mean daily blood glucose (BG), hypoglycemia <70 and <54 mg/dL, and nocturnal hypoglycemia. We also calculated the mean absolute relative difference (MARD), ±15%/15 mg/dL, ±20%/20 mg/dL, and ±30%/30 mg/dL and error grid analysis between matched glucose pairs. RESULTS Mean daily glucose was significantly higher by POC (188.9 ± 37.3 vs. 176.1 ± 46.9 mg/dL) with an estimated mean difference of 12.8 mg/dL (95% CI 8.3–17.2 mg/dL), and proportions of patients with glucose readings <70 mg/dL (14% vs. 56%) and <54 mg/dL (4.1% vs. 36%) detected by POC BG were significantly lower compared with CGM (all P < 0.001). Nocturnal and prolonged CGM hypoglycemia <54 mg/dL were 26% and 12%, respectively. The overall MARD was 14.8%, ranging between 11.4% and 16.7% for glucose values between 70 and 250 mg/dL and higher for 51–69 mg/dL (MARD 28.0%). The percentages of glucose readings within ±15%/15 mg/dL, ±20%/20 mg/dL, and ±30%/30 mg/dL were 62%, 76%, and 91%, respectively. Error grid analysis showed 98.8% of glucose pairs within zones A and B. CONCLUSIONS Compared with POC, FreeStyle Libre CGM showed lower mean daily glucose and higher detection of hypoglycemic events, particularly nocturnal and prolonged hypoglycemia in hospitalized patients with T2D. CGM’s accuracy was lower in the hypoglycemic range.

Implementation of Continuous Glucose Monitoring in the Hospital: Emergent Considerations for Remote Glucose Monitoring During the COVID-19 Pandemic

“…The CGM accuracy was lower for glucose values <70 mg/dL. 10 There are other factors to consider that may impact CGM accuracy and reliability. Reports of infections, skin reactions, or open wounds are rare.…”

“…In this commentary, we hope to provide practical advice to HCW trying to implement this technology in the hospital to preserve critical resources (PPE), reduce nursing burden, and reduce exposure risk. Our recommendations are based on our clinical and recent research experience with CGM in the hospital setting, [7][8][9][10] which includes ongoing clinical trials (NCT03508934 and NCT03877068).…”

“…6 Intravenous CGM devices may provide higher accuracy than SC devices, particularly during surgery, but implementation is more time consuming and complex. 18 The FreeStyle Libre may overestimate lower glucose levels in both ICU and non-ICU patients, 9,10,18 particularly in the perioperative period. 18 Similar findings have been observed in patients undergoing coronary artery bypass graft surgery with the G6 (FJP, personal communication).…”

Continuous Glucose Monitors and Automated Insulin Dosing Systems in the Hospital Consensus Guideline

“…94 A recent study of patients with T2DM admitted to general medicine and surgery wards and managed with basalbolus insulin therapy compared the FreeStyle Libre Pro (Abbott Diabetes Care, Alameda, CA, USA) 95 to POC BG testing. 96 This CGM system is a variant of the FreeStyle Libre 14-day system, where glucose readings are available to the HCP but not to the patient. The FreeStyle Libre Pro CGM, compared to POC BG testing, showed a tendency toward lower mean glucose with an estimated mean glucose difference of 12.8 mg/dL (confidence interval [CI] 8.3-17.2).…”

“…A Clarke error grid analysis showed acceptable clinical accuracy with 98.0% of glucose concentrations falling into Zones A (75.1%, n = 1184) and B (23.7%, n = 374). 96 Panelists reviewed CGM studies in the non-ICU in adult populations (Table 5). 40, 43, 93, 96 -103 Evidence suggests that initiating the use of CGMs in the non-ICU settings provides better glycemic monitoring, compared to standard 3-4 times daily POC BG testing, with improved detection and potential prevention of hypo- and hyperglycemic events.…”