The nuts and bolts of achieving end points with real-time continuous glucose monitoring

Real-time continuous glucose monitoring (RT-CGM) provides detailed information on glucose patterns and trends and promises to be a major advance in diabetes care. To derive full potential benefit from RT-CGM, the patient needs to be skilled in diabetes self-management. In addition, several key concepts and issues need to be addressed in training patients to use RT-CGM. These include 1) the implications of the physiologic lag between interstitial and capillary blood glucose levels and 2) the increased risk among RT-CGM users for hypoglycemia related to blind postprandial bolusing. Patients need to understand the importance of calibrating during steady-state conditions to improve sensor accuracy. In addition, they need to use fingerstick measurements for treatment decision-making when the glucose level is changing rapidly, i.e., conditions when physiologic lag can lead to a marked discrepancy between blood and interstitial glucose. Consideration of "insulin on board" and the impact of the glycemic index of different foodstuffs on postprandial glucose patterns can help minimize the risk for hypoglycemia from supplemental boluses taken to correct postprandial hyperglycemia. To use continuous glucose data safely and effectively, patients need to be skilled in diabetes self-management, and the widespread adoption of RT-CGM into diabetes care will need to be coupled with comprehensive self-management education.