Continuous Blood Glucose Monitoring Outcomes in Veterans With Type 2 Diabetes
Background: Nearly 25% of patients served in the US Department of Veterans Affairs have been diagnosed with type 2 diabetes mellitus (T2DM). Patients with DM typically monitor their blood glucose using intermittent fingerstick self-testing. Continuous glucose monitoring (CGM) might offer improved disease management.
Methods: We conducted a retrospective of VA patient records using a pre–post model. Average hemoglobin A 1c (HbA 1c ) values were calculated for the year before and the year after CGM initiation. Our primary objective was to determine change in HbA 1c from the year before CGM initiation to the year after. Secondary objectives included changes in blood pressure, weight, and DM-related hospital and clinic visits during the same time frame.
Results: Both the total population and the adherent subgroup showed reduction in HbA 1c . The complete population showed a HbA 1c change of –0.3, and the adherent subgroup had a change of –1.3. The total population had a mean change in weight of –1.9 lb (–0.9 kg), and the adherent subgroup had an average change of –8.0 lb. Average systolic blood pressure changes were –0.1 mm Hg in the total population and +3.3 mm Hg in the adherent subgroup. A decrease in total encounters for DM complications was observed in the total population (–0.3 total encounters per patient) and the adherent subgroup (–0.6 total encounters per patient).
Conclusions: CGM did not correspond with clinically significant reductions in HbA 1c . However, veterans with increased health care engagement were likely to achieve clinically significant HbA 1c improvements. Adherent patients also had more reduction in weight and hospital or clinic visits with CGM compared with the total population.
Strengths of this study include specificity to the veteran population using VA resources, as well as including nondiabetes outcomes. This allows for specific application to the veteran population and could provide broader evidence for CGM use. Demonstrated decreases in HbA1c, weight, and clinic visits in the adherent population suggest that providing veterans with CGM therapy with frequent endocrinology follow-up improves health outcomes and could decrease overall health spending.
Limitations
Limitations of this study include retrospective design, a small sample size, and solely focusing on T2DM. As a retrospective study, we cannot rule out the influence of outside factors, such as participation in a non-VA weight loss program. This study lacked the power to assess the impact of the different CGM brands. The study did not include data on severe hypoglycemic or hyperglycemic episodes as veterans might have needed emergent care at non-VA facilities. Future research will evaluate the impact of CGM on symptomatic and severe hypoglycemic episodes and use of insulin vs oral or noninsulin antihyperglycemics and the comparative efficacy of different CGM brands among veterans.
Conclusions
CGM did not correspond with clinically significant reductions in HbA1c. However, veterans with increased health care engagement were likely to achieve clinically significant HbA1c improvements. Adherent patients also had more reduction in weight and hospital or clinic visits with CGM compared with the total population. These veterans’ increased involvement in their health care might have led to better dietary and exercise adherence, which would have decreased insulin dosing and contributed to weight loss.
