Objective: To determine the benefits of personal continuous glucose monitoring (CGM) outside of a controlled clinical trial in a single ambulatory diabetes clinic.
Methods: In this retrospective study, we reviewed medical records of all patients who began CGM in our university-based clinical practice between July 2006 and October 2008. Data pertaining to 1 year before initiation of CGM through January 2009 were collected. All patient visits were performed by any 1 of 7 board-certified endocrinologists and/or 5 certified diabetes educators. A severe hypoglycemic event was considered to have occurred if the patient reported requiring assistance or losing consciousness, or if there was documentation from another source (eg, an emergency department visit). Analysis of the effect of CGM on hemoglobin A1c and occurrence of severe hypoglycemia was performed.
Results: A total of 117 patients initiated CGM between July 2006 and October 2008 and used CGM for at least 2 months (total experience on CGM, 1136 patient-months; average 9.7 months per patient). Mean age was 44.5 +/- 12.8 years (range, 14.3-71.7 years), and average duration of diabetes mellitus was 23.9 years. All patients were using insulin pumps before initiation of CGM, including 10 patients with type 2 diabetes. Sixty-eight patients (58%) had preexisting hypoglycemia unawareness. Average hemoglobin A1c level for 1 year before CGM initiation was 7.6 +/- 1.1%, and with CGM use it dropped to 7.2 +/- 0.8% (P<.001). Forty-two patients had severe hypoglycemic events in the year before CGM use or during CGM use. Overall, CGM use was associated with a significant decrease in the rate of severe hypoglycemic episodes (odds ratio, 0.40; 95% confidence interval, 0.24-0.65).
Conclusions: Personal CGM, in a real-world setting, improves glucose control and reduces the rate of severe hypoglycemic episodes.