Continuous Glucose Monitoring vs Fingerstick Monitoring for Hemoglobin A_1c Control in Veterans

Background: Patients with diabetes have traditionally been required to use fingerstick testing to self-monitor their glucose levels. However, continuous glucose monitors (CGMs) collect glucose readings throughout the day and display daily trends, which allow clinicians to individualize treatment to achieve hemoglobin A_1c (HbA_1c) goals and simplify medication regimens. While studies have shown that CGMs improve HbA_1c levels compared to fingerstick testing, this research has focused on type 1 diabetes and excluded veterans and patients on insulin therapy.

Methods: This retrospective chart review used a crossover, self-controlled design conducted at the Veterans Affairs Sioux Falls Health Care System. Veterans with an active CGM prescription were included. The primary endpoint compared the change in HbA_1c before and after initiation of a CGM.

Results: The mean baseline HbA_1c for the 150 veterans included in this study was 8.6%. The change in HbA_1c before CGM use was 0.003 and change in HbA_1c after CGM use was -0.971. The primary endpoint of difference in HbA_1c associated with CGM use was -0.969 (P = .0001). The overall mean change in total daily doses of insulin was -22 units. Subgroup analysis of change in HbA_1c after CGM use by prescriber type was -0.97 for endocrinology, -0.7 for pharmacy, and -1.23 for primary care practitioners. The overall average HbA_1c post-CGM use was similar across all prescriber types at 7.64%.

Conclusions: This study found veterans with type 2 diabetes and on insulin therapy demonstrated a significant reduction in HbA_1c with CGM use compared with their baseline fingerstick monitoring. Use of a CGM may be beneficial in patients who require a reduction in HbA_1c by allowing more precise adjustments to medications to optimize therapy.