The Impact of Continuous Glucose Monitoring Use Versus Nonuse on Clinical and Economic Outcomes in Individuals Using Rapid- and Short-Acting Insulin: A Retrospective Analysis

<b><i>Background:</i></b> CGM is associated with improved diabetes management. Prior studies have evaluated its effects on health care utilization and costs among individuals using insulin, particularly those prescribed rapid- and short-acting regimens. The present study compared clinical and economic outcomes between CGM users and nonusers in a large, diverse, real-world population of rapid- and short-acting insulin users. <b><i>Methods:</i></b> Using the Mariner Commercial Claims Database, adults with diabetes and at least one claim for rapid- or short-acting insulin between January 1, 2010, and October 31, 2022, were identified. Two cohorts were defined based on receipt of CGM: those with CGM (wCGM) and those without CGM (xCGM). Direct matching was applied to ensure comparability between groups. Outcomes included total medical costs, emergency room (ER) days, inpatient (IP) days, ER and IP days associated with hypoglycemia, diabetic ketoacidosis (DKA), or mixed events, and the likelihood of achieving glycated hemoglobin (HbA1c) <9%. The National Committee for Quality Assurance considers HbA1c >9% as "poor control". <b><i>Results:</i></b> After applying exclusion criteria, 3,139,979 individuals met inclusion criteria. Of these, 536,512 received a CGM and 2,603,467 did not, meaning approximately 83% of eligible individuals had no evidence of CGM use. Total health care costs were significantly lower in the wCGM cohort ($6,245) compared with the xCGM cohort ($7,786; <i>t</i>(698,086) = -71.41, <i>P</i> < 0.001). The wCGM group also had significantly fewer ER days and IP days at 3, 6, 9, and 12 months. CGM users had 19% higher odds of achieving HbA1c <9% compared with nonusers (odds ratio [OR] = 1.19). A significantly smaller proportion of individuals in the wCGM cohort had ER/IP days associated with hypoglycemia, DKA, or both. <b><i>Conclusions:</i></b> These findings reinforce the clinical and economic value of CGM and support recent policy updates expanding access for insulin-treated populations.