Initiation of Continuous Glucose Monitoring Is Linked to Improved Glycemic Control and Fewer 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 (T1D) and type 2 diabetes (T2D) with regard to longer- term glucose control and serious clinical events. RESEARCH DESIGN AND METHODS A retrospective observational cohort study within the Veterans Affairs Health Care Systemwas used to compare glucose control and hypoglycemia- or hyperglycemia-related admission to an emergency room or hospital and all-cause hospitalization between propensity score overlap weighted initiators of CGMand nonusers over 12months. RESULTS CGM users receiving insulin (n = 5,015 with T1D and n = 15,706 with T2D) and similar numbers of nonuserswere identified from1 January 2015 to 31 December 2020. Declines in HbA1c were significantly greater in CGM users with T1D (20.26%; 95% CI 20.33, 20.19%) and T2D (20.35%; 95% CI20.40,20.31%) than in nonusers at 12months. Percentages of patients achieving HbA_1c <8 and <9% after 12 months were greater in CGM users. In T1D, CGM initiation was associated with significantly reduced risk of hypoglycemia (hazard ratio [HR] 0.69; 95% CI 0.48, 0.98) and all-cause hospitalization (HR 0.75; 95% CI 0.63, 0.90). In patients with T2D, there was a reduction in risk of hyperglycemia in CGM users (HR 0.87; 95% CI 0.77, 0.99) and all-cause hospitalization (HR 0.89; 95% CI 0.83, 0.97). Several subgroups (based on baseline age, HbA1c, hypoglycemic risk, or follow-upCGMuse)had even greater responses. CONCLUSIONS In a large national cohort, initiation of CGM was associated with sustained improvement in HbA1c in patients with later-onset T1D and patients with T2D using insulin. This was accompanied by a clear pattern of reduced risk of admission to an emergency roomor hospital for hypoglycemia or hyperglycemia and of all-cause hospitalization.