PracticeUpdate: Diabetes

CONFERENCE COVERAGE 26

Inpatient Diabetes

Long-Term Implantable Continuous GlucoseMonitoring SystemSafe and Accurate in TeensWith Type 1 Diabetes Sensor can stay implanted for up to 180 days

Management Guidelines – Use of the Insulin Pump and CGM By Jason Sloane MD P rior to his meeting with a team of other healthcare providers in the coming months to make major changes to the inpatient diabetes ther- apy guidelines, Dr. Guillermo Umpierrez took time to discuss the advantages of continuing insulin pump therapy and continuous glucose monitoring (CGM) in the hospital. About one-third of patients use insulin pumps, and studies have shown that there is no dif- ference in time spent in range between patients on pumps versus patients receiving multiple daily injections ( J Diabetes Sci Technol. 2012;6[5]:995- 1002). Unfortunately, there are currently no randomized controlled trials of inpa- tient insulin pump therapy to provide better evidence. There are contrain- dications to continuing insulin pump therapy that include healthcare provider comfort level using the device, patient encephalopathy, patient without ade- quate sight or dexterity, and patient unwillingness. As far as inpatient use of CGM, the consensus is that there is benefit with CGM in achieving less hypoglycemia; however, again there are no randomized controlled trials. A recent meta-analysis of the inpatient use of CGM devices showed that there was no improvement in glycemic control compared with conventional capillary blood glucose monitoring. Also, there is only one device on the market that has been approved for use in the inten- sive care unit. The problems with using CGM devices in hospitalized patients are the lag time in measuring blood glu- cose (usually 15 minutes or so behind plasma levels), substance/drug inter- ference, and lack of data using CGM in the setting of hypothermia, hypoxia, or hypotension. Outside the ICU, Dr. Umpierrez recommends using a CGM device in hospitalized patients at higher risk for developing hypoglycemia, such

By the PracticeUpdate Editorial Team T he first long-term implantable con- tinuous glucose monitoring system (CGM; Eversense® XL, Senseonics, Maryland, USA) was shown to be safe and accurate through 180 days of sensor wear in a primarily adolescent population. Most people living with diabetes need to be aware of their blood glucose levels in real time. Traditionally, blood glucose monitoring is done by finger-pricking and applying the drop of blood to a blood glu- cose meter. There are also implantable monitoring systems currently available; one can be implanted for 1 week and another for 2 weeks. Systems implanted under the skin, which enables sensors to stays in place, are paired with a wearable transmitter that sits on the skin. The transmitter receives the sugar sig- nal from the sensor and transmits this value via Bluetooth to a smart phone or other device. “The transmitter also provides an alert to the user if the blood sugar level is going too high or too low by a simple vibra- tion on the skin, which is a big advancement over the alarm systems that traditional sen- sors use,” Ronnie Aronson, MD, founder and Chief Medical Officer of LMC Diabetes & Endocrinology in Toronto, said in an inter- view with Elsevier’s PracticeUpdate . Dr. Aronson said that the technology for this system has been in development for over a decade and has been tested on more than 1,000 adults in various studies. This was the first study involving a pediatric population. The implant is also the first to be tested in a pediatric population for more than 14 days. “Basically, what we found…is that it is a safe and durable alternative to what is currently available, in that it showed excellent accu- racy throughout the entire 180-day period,” Dr. Aronson noted. The study was a prospective, single-center, single-arm evaluation of the effectiveness and safety of the implantable system among 30 Canadian adolescents and 6 Canadian adults with type 1 diabetes. (The mean age of participants was 17 ± 9.2 years.) The accuracy of the sensor was measured by different methods including mean abso- lute relative difference (MARD). After the sensor was inserted, participants stayed in the hospital for a full day, during which time

several blood samples were drawn (initially about every 15 minutes and then every half hour). Blood glucose levels from these sam- ples were measured with the Yellow Springs Instrument (YSI) analyzer and compared to the implanted sensor reading. The relative differences from paired readings were aver- aged to give the MARD. According to Dr. Aronson, a MARD value under 10% is con- sidered very good. The overall MARD from the study was 9.4% (95% CI 8.6–10.5%). Another method used to assess accuracy was determining if the CGM system was in agreement with YSI glucose measurements within 15 mg/dL or 15% of YSI glucose values at least over 80% of the time. The meas- urements (n=7,163) taken at 60, 120, and 180 days, were in agreement 82.9% (95% CI 78.4–86.1%), 83.6% (95% CI 80.4–85.7%), and 83.4% (95% CI 79.7–85.5%) of the time at each time point, respectively. The safety assessment included the incidence of insertion or removal proce- dure-related and device-related serious adverse events through 180 days post-inser- tion. No events were reported. According to Dr. Aronson, “A lot of people worry that if you have to do a small procedure to put this under the skin, then it is going to be a problem for people. What we found is that it is a simple office procedure that our doc- tors are able to learn very quickly, that the patients tolerated very well, and there were no significant adverse events from the pro- cedure and no infections.” The investigators also collected feedback from the participants. According to Dr. Aron- son, “We had a series of questions that we asked all the teens and the adults…. Ninety percent [enjoyed the ability to display glu- cose readings on their devices], 79% liked the sensor duration of 180 days, 76% did not experience any pain or discomfort when using the sensor, 87% liked the [vibratory alert], and 82% found it easy to use.” At this time, the US Food and Drug Admin- istration has approved the pre-market approval (PMA) application to sell the CGM system for 3-month use. The system is already available in Europe for this time- frame. www.practiceupdate.com/c/70046

as those with renal failure. www.practiceupdate.com/c/70307

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