Continuous glucose monitoring continues to show promise: studies

By Megan Brooks NEW YORK (Reuters Health) – Continuous glucose monitoring (CGM) improved diabetes control and reduced glucose variability and was well liked in two studies of patients with type 1 diabetes using multiple daily insulin injections. Both studies were published today in JAMA. The DIAMOND study enrolled 158 patients on multiple daily insulin injections and a baseline hemoglobin A1c (HbA1c) of 7.5% to 9.9%. One hundred and five patients were randomly assigned to the Dexcom G4 Platinum CGM System from Dexcom Inc, which funded the study, and 53 to self-monitored blood glucose (SMBG). After 24 weeks, HbA1c levels were reduced from baseline by 1.1% at 12 weeks and by 1.0% at 24 weeks in the CGM group, versus reductions of 0.5% and 0.4% in the SMBG, with a significant difference at 24 weeks of −0.6% (95% confidence interval, −0.8% to −0.3%; p<0.001). At 24 weeks, 18% CGM patients had HbA1c levels below 7.0% versus 4% of SMBG patients (P=0.01). In addition, CGM was associated with greater time in the glucose range of 70 through 180 mg/dL and less time with glucose levels above 180 mg/dL or lower than 70 mg/dL. CGM was also associated with less glycemic variability. Severe hypoglycemia occurred in two patients in each group and diabetic ketoacidosis did not occur in any patient. Patients who received CGM reported high satisfaction with this method of monitoring. “This is the first randomized trial to assess the value of CGM in patients with type 1 diabetes who receive insulin by injection,” first author Dr. Roy Beck of the Jaeb Center for Health Research in Tampa, Florida, told Reuters Health by email. “In prior studies that I and others have done showing the benefits of CGM for patients with type 1 diabetes, almost all of the participants used an insulin pump to deliver insulin. So this study is important for the literature in showing that CGM benefits of similar magnitude occur in injection users. The results also are important for the literature in showing that there was daily or near-daily use of CGM after 6 months by almost all of the study participants and that satisfaction with using CGM was very high,” Dr. Beck said. He added, “We have been seeing increases in CGM use over the last couple of years in patients with type 1 diabetes using pumps. The data from this study showing not only glycemic benefits but also a high degree of satisfaction with CGM by injection users should have the effect of increasing patient interest in using CGM as well as endocrinologist enthusiasm for prescribing it. Most insurance companies now cover CGM and CMS (Centers for Medicare and Medicaid Services) very recently approved coverage through Medicare. So, I expect we will see substantial increases in CGM use over the next year.” The GOLD study compared CGM (also using the Dexcom G4 system) to SMBG in a crossover randomized study involving 161 patients who were using multiple daily insulin injections and had baseline HbA1c levels of at least 7.5%. Each study intervention period lasted 26 weeks with a 17-week washout period between CGM and SMBG. Compared with a baseline HbA1c level of 8.6%, HbA1c levels at the end of the intervention period were 7.9% with CGM and 8.4% with SMBG, with a difference of −0.4% (95% CI, −0.6% to −0.3%; p<0.001). There was one severe hypoglycemia event in the CGM group and five in the SMBG group. Glucose variability was significantly lower in the CGM group. Patients reported greater satisfaction with CGM. Commenting on the study, lead investigator Dr. Marcus Lind of the University of Gothenburg, Sweden, noted that the DexCom G4 sensor has shown “high accuracy and positive treatment experience” in short evaluations, but has not been evaluated thoroughly in randomized trials until now. This study, he said, “shows that this sensor gives better glycemic control in adults with type 1 diabetes treated with multiple daily insulin injections than using regular capillary glucose testing. Such data are needed for decision-makers to decide whether to recommend the use of CGM in persons treated with injections. Further, the study showed an effect on well-being, which has not earlier been shown in randomized trials regarding CGM. Patients felt more confident regarding risks of hypoglycemia. Further, the glycemic variability was reduced. Of note, in spite of improving several factors, there were no indications of harmful effects.” In a linked editorial, Dr. Mayer Davidson of Charles R. Drew University of Medicine and Science in Los Angeles writes, “Additional clinical trials are needed to determine the long-term effect of CGM and whether this approach translates to improved health outcomes and to determine the potential utility of real-time CGM for patients with type 1 diabetes encountered in usual clinical practice and in patients with type 2 diabetes who require insulin injections.” Funding for the DIAMOND study was provided by Dexcom Inc. Several authors reported financial relationships with the company. The GOLD study was investigator-initiated and sponsored by the NU Hospital Group, Trollhättan and Uddevalla, Sweden. Several authors disclosed relationships with various companies including Dexcom Inc. SOURCE: http://bit.ly/2jmuahY, http://bit.ly/2jmz2Dw and http://bit.ly/2jmI8jZ JAMA 2017.