The cost burden of diabetes is significant. In 2007, the total costs associated with the disease were estimated at $174 billion (ADA 2008). Patients diagnosed with diabetes incur 2.3 times higher medical expenditures than those without the disease. Hypoglycemia severe enough to warrant third-party intervention results in mean costs exceeding $1,000 per episode (Bullano 2005, Heaton 2003).
Several landmark trials have confirmed that tighter control of diabetes improves clinical outcomes (UKPDS Group 1998, DCCTRG 1993). The adoption of an intensive form of diabetes management can, however, come with increased risk, as was reported in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial (NHLBI 2008). There is speculation that the increased risk of cardiovascular death may be due to higher baseline cardiovascular risk; however, this has yet to be confirmed. Intensive management of diabetes would, therefore, require close monitoring of glycemic control with the goal of maintaining blood glucose levels within a defined optimal range (70–180 mg/dL) (ADA 2005).
Continuous glucose monitoring (CGM) provides greater information regarding glycemic control than episodic blood glucose measurements. CGM has the ability to indicate a rate of change both in numeric form and through the use of prospective, directional trend arrows. In addition, alarms are activated when glucose levels approach critical hypoglycemic or hyperglycemic values. CGM provides the patient and health care provider with access to retrospective continuous glucose data over clinically relevant periods of time (Garg 2006, Deiss 2006). These features result in systems that provide trend information that can guide treatment decision making.
This is a report of a study examining the accuracy of the FreeStyle Navigator Continuous Glucose Monitoring System (Abbott Diabetes Care, Abbott Park, Ill.) in the home environment and patient assessment of its use. The device and its performance in a clinical setting have been described previously (Weinstein 2007).