Effects of unrestricted access to flash glucose monitoring in type 1 diabetes

We assessed adherence and long-term effects on HbA1c of unrestricted access to flash glucose monitoring (FGM) in a single diabetes centre.

In this observational study, we reviewed data files for all 411 patients with type 1 diabetes attending our clinic during a 2-year period. Adherence was reported in those who initiated FGM in our clinic (n = 321). Baseline and final HbA1c were noted for patients who continued FGM for more than 6 months without clinical conditions or interventions at baseline that could interfere with the effect of FGM on glycaemic control (n = 270).

After 2 years, the fraction of patients using FGM increased from 3% to 72%. Adherence to FGM was 88%. Baseline and final HbA1c was median (interquartile range) 63 mmol/mol (56, 74) (7.9% (7.3, 8.9)) and 59 mmol/mol (53, 68) (7.6% (7.0, 8.4)), respectively. The estimated difference final-baseline HbA1c was -4 mmol/mol (95% CI -5, -3) (-0.4% (-0.5, -0.3)) (P < .001). No significant difference was seen for patients with baseline HbA1c ≤ 7% (53 mmol/mol). The interval from initiation of FGM to final HbA1c was median 562 days (IQR 417, 662). The number of scans/day was median 11 (IQR 8, 13) and correlated negatively with both final and baseline HbA1c but not with change in HbA1c.

Following the introduction of unlimited access, nearly three quarters of the patients were FGM users. Long-term adherence was good, and HbA1c improved in all patients except in those with optimal glycaemic control at baseline.