REFER investigated the impact of the FreeStyle Libre system on A1c in type 2 diabetes (T2D) managed with basal-bolus insulin treatment.1 Real-world data were collected in 3 parallel, retrospective, non-interventional chart review studies of type 2 diabetes patients using the FreeStyle Libre system at diabetes centres in Austria, France and Germany. In these real-world settings, using the FreeStyle Libre system for 3–6 months significantly reduced A1c levels in people with T2D managed with basal-bolus insulin therapy.
REFER study
FreeStyle Libre system in T2D with basal-bolus insulin
Evaluating the FreeStyle Libre system in type 2 diabetes managed with basal-bolus therapy
Study design and study population
REFER comprised 3 parallel, retrospective, non-interventional, single-arm chart review studies conducted in Austria, France and Germany (6 centres per country).
Inclusion criteria

- ≥18 years
- T2D
- On basal-bolus insulin regimen for ≥1 year
- Use of FreeStyle Libre system for ≥3 months at time of data collection
- Baseline A1c of 64–108 mmol/mol (8.0 %-12.0%)
- A1c measurement 3–6 months after initiation of device use
Key exclusion criteria

- Pregnancy
- Receiving dialysis treatment
- Participation in a conflicting study
Primary outcome
Subgroup analyses (all countries)
Baseline A1c
<75 mmol/mol (<9.0%)
≥75 mmol/mol (≥9.0%)
Duration of insulin use
<9 years
≥9 years
Age
<65 and ≥65 years
BMI
<30 and ≥30
Sex
Study results
Key patient baseline characteristics1
A total of 363 medical records were included in the meta-analysis (92 from Austria, 88 from France and 183 from Germany). Baseline demographic and clinical characteristics were similar across all countries (Table 1, Fig 1).
Primary outcome
Figure 1 – Change in A1c from baseline per country and overall
Subgroup analyses
In all three countries:
➤ A1c decrease was more pronounced in patients with baseline A1c levels ≥75 mmol/mol (≥9.0%) (Fig 2).
➤ A1c improvements were seen across age, sex, duration of insulin use and BMI categories (Fig 2).
➣ No significant difference in A1c effects was seen between subgroups of these categories.
Figure 2 – Change in A1c from baseline per subgroup analysis
Summary
REFER was the first analysis of real-world data to demonstrate the beneficial impact of FreeStyle Libre system on A1c levels in type 2 diabetes patients treated with basal-bolus insulin.
After 3–6 months of use, the FreeStyle Libre system significantly reduced A1c levels in T2D patients on a basal-bolus insulin regimen.
Study data collected with the FreeStyle Libre system and is applicable to the FreeStyle Libre 2 & FreeStyle Libre 3 systems based on technological similarities.†If >1 A1c test result was available, the result closest to the index date was extracted for use. ‡Test performed ≥90 days but <194 days after initiating Freestyle Libre; if >1 A1c result was available, the result closest to 135 days after the index date was used.
References
1 Kröger J, Fasching P, Hanaire H. Three European retrospective real-world chart review studies to determine the effectiveness of flash glucose monitoring on A1c in adults with type 2 diabetes. Diabetes Ther. 2020;11(1):279-291. doi:10.1007/s13300-019-00741-9.
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