Effect of Flash Glucose Monitoring on Glycemic Control, Hypoglycemia, Diabetes-Related Distress, and Resource Utilization in the Association of British Clinical Diabetologists (ABCD) Nationwide Audit

Abstract

Objective: The FreeStyle Libre (FSL) flash glucose-monitoring device was made available on the U.K. National Health Service (NHS) drug tariff in 2017. This study aims to explore the U.K. real-world experience of FSL and the impact on glycemic control, hypoglycemia, diabetes-related distress, and hospital admissions.

Research design and methods: Clinicians from 102 NHS hospitals in the U.K. submitted FSL user data, collected during routine clinical care, to a secure web-based tool held within the NHS N3 network. The t and Mann-Whitney U tests were used to compare the baseline and follow-up HbA_1c and other baseline demographic characteristics. Linear regression analysis was used to identify predictors of change in HbA_1c following the use of FSL. Within-person variations of HbA_1c were calculated using [Formula: see text].

Results: Data were available for 10,370 FSL users (97% with type 1 diabetes), age 38.0 (±18.8) years, 51% female, diabetes duration 16.0 (±49.9) years, and BMI of 25.2 (±16.5) kg/m² (mean [±SD]). FSL users demonstrated a -5.2 mmol/mol change in HbA_1c, reducing from 67.5 (±20.9) mmol/mol (8.3%) at baseline to 62.3 (±18.5) mmol/mol (7.8%) after 7.5 (interquartile range 3.4-7.8) months of follow-up (n = 3,182) (P < 0.0001). HbA_1c reduction was greater in those with initial HbA_1c ≥69.5 mmol/mol (>8.5%), reducing from 85.5 (±16.1) mmol/mol (10%) to 73.1 (±15.8) mmol/mol (8.8%) (P < 0.0001). The baseline Gold score (score for hypoglycemic unawareness) was 2.7 (±1.8) and reduced to 2.4 (±1.7) (P < 0.0001) at follow-up. A total of 53% of those with a Gold score of ≥4 at baseline had a score <4 at follow-up. FSL use was also associated with a reduction in diabetes distress (P < 0.0001). FSL use was associated with a significant reduction in paramedic callouts and hospital admissions due to hypoglycemia and hyperglycemia/diabetic ketoacidosis.

Conclusions: We show that the use of FSL was associated with significantly improved glycemic control and hypoglycemia awareness and a reduction in hospital admissions.

Figure 1

Study schematic showing data for HbA_1c, Gold score, and DDS score in the ABCD nationwide audit of FSL. Study outline shows the number of patients recruited in the study and sample size of those with follow-up for HbA_1c, Gold score, and DDS score.

Figure 2

Indications for starting FSL in the ABCD nationwide audit of FSL. Multiple indications for FSL initiation in the study population are shown. Hypo, hypoglycemia; SMBG, self-monitoring of blood glucose.

Figure 3

Distribution of HbA_1c change pre- and post-FSL use in the ABCD nationwide audit of FSL in the study population (A) and in those with a baseline HbA_1c of ≥69.5 mmol/mol (B).

Figure 4

DDS score (DDSC) before and after use of FSL in the ABCD nationwide audit of FSL. Shown is the change in the two components of the DDS score before and after FSL initiation. The DDS2 asks respondents to rate on a six-point scale the degree to which the following items caused distress: 1) “feeling overwhelmed by the demands of living with diabetes,” and 2) “feeling that I am often failing with my diabetes regimen.”

Figure 5

Total number of paramedic callouts, severe hypoglycemia, and hospital admissions during the 12 months before and the 7.5 months of follow-up using FSL in the ABCD nationwide audit. This image shows the change in type 1 diabetes–related resource utilization following FSL initiation.