Cost-effectiveness of Continuous Glucose Monitoring for Adults With Type 1 Diabetes Compared With Self-Monitoring of Blood Glucose: The DIAMOND Randomized Trial

OBJECTIVE This study evaluated the societal cost-effectiveness of continuous glucose monitoring (CGM) in patients with type 1 diabetes (T1D) using multiple insulin injections. RESEARCH DESIGN AND METHODS In the Multiple Daily Injections and Continuous Glucose Monitoring in Diabetes (DIAMOND) trial, 158 patients with T1D and HbA1c ≥7. 5% were randomized in a 2: 1 ratio to CGM or control. Participants were surveyed at baseline and 6 months. Within-trial and lifetime cost-effectiveness analyses were conducted. A modified Sheffield T1D policy model was used to simulate T1D complications. The main outcome was cost per quality-adjusted life-year (QALY) gained. RESULTS Within the 6-month trial, the CGM group had similar QALYs to the control group (0. 462 ± 0. 05 vs. 0. 455 ± 0. 06 years, P = 0. 61). The total 6-month costs were 11, 032 (CGM) vs. 7, 236 (control). The CGM group experienced reductions in HbA1c (0. 60 ± 0. 74% difference in difference DiD), P 0. 01), the daily rate of nonsevere hypoglycemia events (0. 07 DiD, P = 0. 013), and daily test strip use (0. 55 ± 1. 5 DiD, P = 0. 04) compared with the control group. In the lifetime analysis, CGM was projected to reduce the risk of T1D complications and increase QALYs by 0. 54. The incremental cost-effectiveness ratio (ICER) was 98, 108 per QALY for the overall population. By extending sensor use from 7 to 10 days in a real-world scenario, the ICER was reduced to 33, 459 per QALY. CONCLUSIONS For adults with T1D using multiple insulin injections and still experiencing suboptimal glycemic control, CGM is cost-effective at the willingness-to-pay threshold of 100, 000 per QALY, with improved glucose control and reductions in nonsevere hypoglycemia.