Effect of flash glucose monitoring in adults with type 1 diabetes: a nationwide, longitudinal observational study of 14,372 flash users compared with 7691 glucose sensor naive controls

AIMS/HYPOTHESIS

The aim of this work was to evaluate changes in glycaemic control (HbA_1c) and rates of severe hypoglycaemia over a 2 year period after initiation of flash glucose monitoring (FM) in type 1 diabetes.

METHODS

Using data from the Swedish National Diabetes Registry, 14,372 adults with type 1 diabetes with a new registration of FM during 2016-2017 and with continued FM for two consecutive years thereafter, and 7691 control individuals using conventional self-monitoring of blood glucose (SMBG) during the same observation period, were included in a cohort study. Propensity sores and inverse probability of treatment weighting (IPTW) were used to balance FM users with SMBG users. Changes in HbA_1c and events of severe hypoglycaemia were compared.

RESULTS

After the start of FM, the difference in IPTW change in HbA_1c was slightly greater in FM users compared with the control group during the follow-up period, with an estimated mean absolute difference of -1.2 mmol/mol (-0.11%) (95% CI -1.64 [-0.15], -0.75 [-0.07]; p < 0.0001) after 15-24 months. The change in HbA_1c was greatest in those with baseline HbA_1c ≥70 mmol/mol (8.5%), with the estimated mean absolute difference being -2.5 mmol/mol (-0.23%) (95% CI -3.84 [-0.35], -1.18 [-0.11]; p = 0.0002) 15-24 months post index. The change was also significant in the subgroups with initial HbA_1c ≤52 mmol/mol (6.9%) and 53-69 mmol/mol (7.0-8.5%). Risk of severe hypoglycaemic episodes was reduced by 21% for FM users compared with control individuals using SMBG (OR 0.79 [95% CI 0.69, 0.91]; p = 0.0014)].

CONCLUSIONS/INTERPRETATION

In this large cohort, the use of FM was associated with a small and sustained improvement in HbA_1c, most evident in those with higher baseline HbA_1c levels. In addition, FM users experienced lower rates of severe hypoglycaemic events compared with control individuals using SMBG for self-management of glucose control.