Clinical Accuracy of a Continuous Glucose Monitoring System With an Advanced Algorithm

Abstract

Background : We assessed the performance of a modified Dexcom G4 Platinum system with an advanced algorithm, in comparison with frequent venous samples measured on a laboratory reference (YSI) during a clinic session and in comparison to self-monitored blood glucose (SMBG) during home use. Methods:Fifty-one subjects with diabetes were enrolled in a prospective multicenter study. Subjects wore 1 sensor for 7-day use and participated in one 12-hour in-clinic session on day 1, 4, or 7 to collect YSI reference venous glucose every 15 minutes and capillary SMBG test every 30 minutes. Carbohydrate consumption and insulin dosing and timing were manipulated to obtain data in low and high glucose ranges. Results:In comparison with the laboratory reference method (n = 2,263) the system provided a mean and median absolute relative differences (ARD) of 9.0% and 7.0%, respectively. The mean absolute difference for CGM was 6.4 mg/dL when the YSIs were within hypoglycemia ranges (≤ 70 mg/dL). The percentage in the clinically accurate Clarke error grid A zone was 92.4% and in the benign error B zone was 7.1%. Majority of the sensors (73%) had an aggregated MARD in reference to YSI ≤ 10%. The MARD of CGM-SMBG for home use was 11.3%. Conclusions:The study showed that the point and rate accuracy, clinical accuracy, reliability, and consistency over the duration of wear and across glycemic ranges were superior to current commercial real-time CGM systems. The performance of this CGM is reaching that of a self-monitoring blood glucose meter in real use environment.

Clinical Implications of Accuracy Measurements of Continuous Glucose Sensors

“…15 Although most sensor studies have used a laboratory instrument (e.g., YSI-2300; Yellow Springs International Life Sciences) as the comparator, other studies have used or supplemented this with capillary glucose values. [16][17][18] Advantages of capillary data include the ability to obtain a greater number of data points, patients living in ''real-world'' conditions, and that capillary values are those that people with diabetes currently use most frequently to make therapy decisions. SMBG is also the procedure that people with diabetes would most like to replace.…”

Pathologic changes of pancreatic endothelial cells in Diabetic Rat

“…Through a paracrine effect, the Tie is a type of highly homologous tyrosine kinase receptor and its gene location is in 9p21, encoding the 22 amino acids [11]. Ang-1 combine with Tie-2 to be a polymer formation, and then induced the Tie-2 itself phosphorylation and activation, which was through the PIP3/AKT signal pathways to regulate/apoptosis of endothelial cell proliferation, regulating the endothelial cells of budding, migration, chemotaxis and aggregation, etc [12][13][14][15]. In the study, the level of ang-1, tie-2 and VCAM-1 were 585.04 ± 45.32 (pg/ml), 2399.40 ± 124.85 (pg/ml) and 117.69 ± 12.34 (µg/L) in the diabetes groups which were higher than that in control groups 551.29 ± 31.86 (pg/ml), 2103.27 ± 152.89 (pg/ml) and 93.43 ± 10.48 (µg/L), P<0.05, has different statistically significance.…”

Practical Considerations on the Use of Continuous Glucose Monitoring in Pediatrics and Older Adults and Nonadjunctive Use

“…17 With recent advancements in the newer CGM systems, using improved interstitial sensors and advanced system algorithms, MARD has improved to £10% in both pediatric and adult patients, helping to prompt the recent FDA approval for nonadjunctive use. 16 The pediatric study demonstrated an improvement in MARD from 17% to 10% in comparison of the original Dexcom G4 Platinum CGM with the newer 505 algorithm. 18 A recent survey of adolescent and adults with T1D in the United States reported insufficient accuracy as the most frequent reason for patients to dislike using CGM (in 28% of responses).…”

“…14 In the last 5 years, there has been remarkable improvement in CGM device performance, demonstrated by the remarkable improvement in mean absolute relative difference (MARD) of CGM devices. 15,16 For example, the Dexcom SEVEN PLUS (Dexcom, Inc.) had MARD values of 16%-19% in the target range and 20%-40% in the hypoglycemia range. 17 With recent advancements in the newer CGM systems, using improved interstitial sensors and advanced system algorithms, MARD has improved to £10% in both pediatric and adult patients, helping to prompt the recent FDA approval for nonadjunctive use.…”

“…However, the improved accuracy and reliability of CGM devices now approximate the accuracy range reported for BGM. 16 An FDA Advisory Board heard public testimony on July 21, 2016, and recommended that the Dexcom G5 Mobile device be approved for nonadjunctive use, a recommendation accepted by FDA on December 20, 2016. 7 It is worthwhile to review CGM use by healthcare providers, families, and patients.…”