THE COST-EFFECTIVENESS OF CONTINUOUS GLUCOSE MONITORING IN TYPE 1 DIABETES

Purpose: Continuous glucose monitoring (CGM) has been found to improve glucose control in type 1 diabetes patients.  However, the cost-effectiveness of CGM has not been evaluated.  We estimate the incremental cost-effectiveness of CGM for patients with type 1 diabetes patients with sub-optimal (primary cohort, glycated hemoglobin (A1C)≥7.0%) and optimal glucose control (secondary cohort, A1C<7.0%).

Method: The cost-effectiveness analysis (CEA) was conducted from the societal perspective.  Our analysis was limited to JDRF-CGM trial populations where CGM produced a significant glycemic benefit (adult primary cohort, secondary cohort).  Trial subjects were randomized to continuous or standard glucose monitoring for 6 months.  Data on health state utilities (TTOs) and health service utilization were collected routinely.  We calculated incremental cost-effectiveness ratios (ICERs) expressed in 2007 US dollars for the within-trial period and extrapolated long-term (lifetime).costs and benefits using a simulation model of type 1 diabetes complications. 

Results:   During the 6 month trial, CGM subjects experienced a quality of life benefit (adult primary: 0.70 quality-adjusted weeks (QALWs) p=0.49; secondary: 1.39 QALWs, p=0.04) in addition to an improvement in glucose control.  The within-trial ICERs were approximately $400,000/QALY.  In the long-term CEA for the adult primary cohort, CGM was projected to reduce the lifetime probabilities of blindness (14.56→12.00), amputation (10.53→9.13), and end-stage renal disease (ESRD) (4.41→2.37); the average gain in QALYs was 0.60.  The ICER was $98,679/QALY (95% confidence intervals (CI), -60,007 (4^th quadrant), -86,582 (2^nd quadrant).  For the secondary cohort, CGM was also projected to reduce probabilities of microvascular complications; the average gain in QALYs was 1.11.  The ICER was $78,943/QALY (95% CI, 14,644 (1^st quadrant), -290,780 (2^nd quadrant). In sensitivity analyses, if the benefit of CGM had been limited to improved glucose control, the ICER would exceed $400,000/QALY for the adult primary cohort and $900,000/QALY for the secondary cohort.  If daily CGM costs were ≤ $7/day, the ICER would be below $50,000/QALY.

Conclusions: The point estimates of ICERs based on long-term projections from the JDRF-CGM trials indicate that CGM is cost-effective among type 1 patients, although considerable uncertainty surrounds these estimates.  Subgroup analysis demonstrates heterogeneity in the quality of life impact and the economic value of CGM for patients with varying levels of glycemic control.  The value of CGM is greatly influenced by its ability to improve everyday quality of life.