Initiation of continuous glucose monitoring is linked with improved glycemic control and reduced clinical events in type 1 and type 2 diabetes in the Veterans Health Administration

Objective: To determine the benefit of starting continuous glucose monitoring (CGM) in adult-onset type 1 diabetes and type 2 diabetes (T1D; T2D) on longer-term glucose control and serious clinical events.

Research Design and Methods: A retrospective observational cohort study within the VA Health Care System was used to compare glucose control, and hypoglycemia and hyperglycemia related admissions to emergency rooms or hospitals and all-cause hospitalization between propensity score weighted initiators of CGM and non-CGM users over 12-months.

Results: 5,015 T1D and 15,706 T2D CGM users receiving insulin and similar numbers of non-CGM users were identified from 1/1/2015-12/31/2020. Declines in HbA1c were significantly greater in T1D CGM users (-0.26%,CI:-0.33%,-0.19%) and T2D CGM users (-0.35%,CI:-0.40%, -0.31%) than in non-users at 12 months. Percentages of patients achieving HbA1c < 8% and < 9% after 12 months were greater in CGM users.

In T1D, CGM initiation was associated with significantly reduced risk for hypoglycemia (HR: 0.69,CI:0.48-0.98) and all-cause hospitalization (HR 0.75, CI:0.63-0.90). In T2D patients, there was a reduction in risk for hyperglycemia in CGM users (HR 0.87, CI:0.77-0.99) and all-cause hospitalizations (HR 0.89, CI:0.83-0.97). Several subgroups (based on baseline age, HbA1c, hypoglycemic risk or follow-up CGM use) had even greater responses.

Conclusion: In a large national cohort, initiation of CGM was associated with sustained improvements in HbA1c in later-onset T1D patients and T2D patients using insulin. This was accompanied by a clear pattern of reduced risk for admissions to emergency rooms or hospitals for hypoglycemia or hyperglycemia and for all-cause hospitalization.