Real-time continuous glucose monitoring improved glycemic control compared with self-monitoring of blood glucose at 1 year in a recent clinical trial; real-time continuous glucose monitoring was cost-effective for providing modest increases in life expectancy and improved quality of life based on 2 statistical models. Coinvestigator Stephanie J. Fonda, PhD, Walter Reed National Military Medical Center, Bethesda, MD, presented the data at the 2012 ADA annual meeting.
“We used the data from a study we completed that showed a sustained reduction of 1.1% in hemoglobin A1c with real-time continuous glucose monitoring at 1 year compared to a smaller (ie, 0.5%) reduction with self-monitoring of blood glucose to develop 2 different models to project cost-effectiveness, cost of complications, and quality of life,” explained Dr Fonda.
In the recently published study (Vigersky RA, et al. Diabetes Care. 2012; 35:32-38) of patients with type 2 diabetes, 50 patients wore a continuous loop monitor for the real-time continuous glucose monitoring and 50 patients performed self-monitoring of blood glucose during the 3-month intervention period. All patients were then followed until week 52.
The volunteer participants are representative of the motivated population of patients with type 2 diabetes. The volunteers were typically middle-aged (mean age, 57.8 years), overweight or obese (mean body mass index, 32 kg/m2), and mostly men (60%), and they had poorly controlled type 2 diabetes (mean baseline hemoglobin [Hb] A1c , 8.3%). Approximately 35% to 40% of participants were black, reflecting the population in the military medical center. Most of the patients were taking an oral antidiabetic drug, insulin, or both, and the duration of their diabetes was approximately 9 years.
The 2 Analyses
The base-case analysis determined the costs at 5 years for using the intervention exactly as it was used in the clinical trial. The scenario analysis looked at the 5-year costs for adding a second “dose” of real-time continuous glucose monitoring in year 2 as a refresher for the participant. Assumptions included the convergence of HbA1c within 21 months of the intervention and that patients would be taking insulin by year 5. The validated IMS CORE Diabetes model was used to predict economic outcomes and estimated health outcomes in terms of quality-adjusted life-years (QALYs).
The researchers used a US payer perspective to calculate costs and included only direct costs obtained from published sources that were inflated to 2011 US dollars.
In the base-case analysis, an incremental increased cost of $250 versus self-monitoring of blood glucose was associated with a 1.03-month increase in life expectancy and a 0.8-month improvement of QALY with real-time continuous glucose monitoring.
Incremental Cost Reductions in Treating Complications
The incremental cost-effectiveness ratio (ICER) was $2903 for each life-year gained and $3735 for each QALY gained. The following reductions were seen with real-time continuous glucose monitoring in the cost of treating diabetes complications:
- –$177 for cardiovascular diseases
- –$141 for renal disease
- –$212 for diabetic foot complications.
In the scenario analysis, a greater increase was found in life expectancy—2 additional quality-adjusted life- months—than in the base-case analysis. The incremental cost was $1217 for 2 episodes of real-time continuous glucose monitoring (1 each in year 1 and year 2) more than self-monitoring of blood glucose, and the ICER was $10,071 per QALY.
Dr Fonda noted that the cost of the interventions is low, which contributes to the cost-efficacy, and that behavioral interventions are known to have a modest impact when used without feedback from the clinician. A big improvement in glycemic control over the intervention period is being seen, she pointed out.
But the refresher dose of real-time continuous glucose monitoring is needed, because patients begin to regress after approximately a year. Furthermore, feedback from the clinician to enable patients to see the relationships between their eating and exercise habits and their HbA1c levels would likely give greater benefits, she said.
The real-time continuous glucose monitoring could be used for only 2 weeks, because the response is seen in this time frame.