Diabetes Technology Meeting 2004
The fourth annual Diabetes Technology Meeting was held in Philadelpia from October 28-30, 2004. In attendance were over 600 scientists, engineers, and doctors from government, industry, academia, and clinical practice. During the two-and-a-half days of sessions, speakers shared information on a variety of topics, including continuous glucose monitoring, glucose meter and continuous sensor accuracy, insulin delivery alternatives, and various types of computer technologies. Here is a summary of some of the sessions:
- Defining Accuracy in Blood Glucose Monitors, one of three Pre-Meeting Workshops, was packed -- people were standing along the back wall -- demonstrating well the importance of this topic. The following presentations from that workshop were very interesting:
- James Nichols, Ph.D. who spoke first about What is Accuracy and How Close Must the Agreement Be?, noted that from Monte Carlo simulations, finger stick blood glucose monitors needed to have an error rate of 1-2% to allow patients to choose the correct insulin dose 95% of the time. A meter error of 5% yields insulin dosage errors 8-23% of the time, and a 10% meter error yields dosage errors 16-45% of the time. Today's meters typically claim 5-10% error.
- William Clarke, MD, spoke about CG-EGA: Clinical Accuracy for Continuous Monitors. Dr. Clarke, whose name is associated with the Clarke Error Grid used to measure accuracy in blood glucose monitors, spoke about the misuse of that technique when applied to continuous sensors because the error grid analysis was not designed to present data in which one point was related to the previous point. Dr. Clarke noted that with trend data from continuous sensors, the absolute point accuracy may not need to be as good as what is available in current home glucose monitors if the rate of change information from the continuous sensor is good. With this in mind, Dr. Clarke presented a new way to look at accuracy in continuous sensors, called the Rate Error Grid, which is comprised of several different charts that include rate-of-change data in addition to the reported glucose reading.
- Geoff McGarraugh of Abbott Diabetes Care spoke about the Accuracy of Continuous Glucose Sensors. McGarraugh stressed that absolute point accuracy is the wrong question to ask of continuous sensors. He asked, "What do patients really want to know?" Do they want to know that they are low? No, he said -- they want to know before they are low so they can take action to prevent the low. Today's blood glucose monitors typically confirm what the patient already feels -- they're low. Continuous sensors have the potential to alert patients before they find themselves in a situation they'd prever to avoid.
- Sanford Asher, Ph.D., presented Non-Invasive Photonic Crystal Tear Glucose Sensing, a new technology that could be used to measure glucose in tears completely non-invasively. The technology can be used to make a contact lens (prescription or not) that has a small spot that changes color in response to the glucose level in the tears, which corresponds to blood glucose though with a slight time lag. The challenge is the very low amounts of glucose in the tears -- 3 mg/dl to 15 mg/dl -- and making the overall system responsive when the glucose levels are in the hypoglycemic range. For more information, see Photonic Crystal Glucose-Sensing Material for Noninvasive Monitoring of Glucose in Tear Fluid.
- Bruce Buckingham, M.D., presented Potential Advantages of Continuous Blood Glucose Monitoring. He noted that the mean absolute difference -- a measure of accuracy -- for blood glucose monitors from 1989 was essentially the same as the continuous monitors of today. From this he noted the great potential for improved care that we are likely to see from widespread use of continuous sensors. In addition to the benefits of alerting patients to impending hypoglycemia, continuous sensors can also help alert patients to what would otherwise be a prolonged period of hyperglycemia -- notably from forgotten meal boluses. Dr. Buckingham presented data from Dr. Peter Chase that one to two missed meal boluses per week was enough to result in increased HbA1c. For more information see Missed insulin meal boluses and elevated hemoglobin A1c levels in children receiving insulin pump therapy.
- Several presentations covered alternative insulin delivery methods, including inhaled insulin, oral insulin, buccol (mouth mucosa) insulin, and through the skin after ultrasonic energy has been applied. Each of the presenters noted that their delivery method had been shown to work in animals, with inhaled insulin having good data in human trials to show effectiveness. Inhaled, oral, and buccol all require significantly more insulin than traditional injections to achieve the same amount of blood glucose lowering effect.
- Satish Garg, M.D., who spoke about Rapid Acting Insulin Analogs, began his presentation by noting that the average HbA1c for patients seeing primary care physicians was 9.7, and for those seeing endocrinologists was 9.3. Dr. Garg noted that both of these are way above guidelines. He also noted that patients with type 1 diabetes check their blood glucose twice per day on average, type 2 diabetes check their blood glucose only an average of per week on average. He then spoke about the challenge of bringing down HbA1c readings, and spoke about the benefits of rapid acting insulin analogs (NovoLog and Humalog, with more coming) in lowering post-prandial excursions.
Dr. Bruce Buckingham explains the poster about responses to nocturnal alarms in people using the GlucoWatch Biographer
Dr. Satish Garg, who spoke about the benefits of rapid acting insulin analogs, began by reminding the audience of the magnitude of the problem
Dr. William Clarke spoke about the need for a new way to measure accuracy of continuous sensors and offered a way to include direction of change information in a revised measurement scheme
Each evening, attendees reviewed many excellent poster presentations and learned about cutting edge research
Seung Lee received the Peterson Student Research Gold Award and spoke about A Novel Technology for Insulin Delivery using cymbal arrays to deliver ultrasonic energy on the skin