Accuracy of Flash Glucose Monitoring During Postprandial Rest and Different Walking Conditions in Overweight or Obese Young Adults

Aims: To investigate the accuracy of FreeStyle LibreTM flash glucose monitoring (FGM) relevant to plasma glucose (PG) measurements during postprandial rest and different walking conditions in overweight/obese young adults.Methods: Data of 40 overweight/obese participants from two randomized crossover studies were pooled into four trials: (1) sitting (SIT, n = 40); (2) walking continuously for 30 min initiated 20 min before individual postprandial glucose peak (PPGP) (20iP + CONT, n = 40); (3) walking continuously for 30 min initiated at PPGP (iP + CONT, n = 20); and (4) accumulated walking for 30 min initiated 20 min before PPGP (20iP + ACCU, n = 20). Paired FGM and PG were measured 4 h following breakfast.Results: The overall mean absolute relative difference (MARD) between PG and FGM readings was 16.4 ± 8.6% for SIT, 16.2 ± 4.7% for 20iP + CONT, 16.7 ± 12.2% for iP + CONT, and 19.1 ± 6.8% for 20iP + ACCU. The Bland–Altman analysis showed a bias of −1.03 mmol⋅L–1 in SIT, −0.89 mmol⋅L–1 in 20iP + CONT, −0.82 mmol⋅L–1 in iP + CONT, and −1.23 mmol⋅L–1 in 20iP + ACCU. The Clarke error grid analysis showed that 99.6–100% of the values in all trials fell within zones A and B.Conclusion: Although FGM readings underestimated PG, the FGM accuracy was overall clinically acceptable during postprandial rest and walking in overweight/obese young adults.

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Comparison of Interstitial Fluid Glucose Levels Obtained by Continuous Glucose Monitoring and Flash Glucose Monitoring in Patients With Type 2 Diabetes Mellitus Undergoing Hemodialysis

Journal of Diabetes Science and Technology ◽

10.1177/1932296819882690 ◽

2019 ◽

Vol 14 (6) ◽

pp. 1088-1094 ◽

Cited By ~ 3

Author(s):

Takahiro Yajima ◽

Hiroshi Takahashi ◽

Keigo Yasuda

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Interstitial Fluid ◽

Glucose Monitoring ◽

Relative Difference ◽

Flash Glucose Monitoring ◽

Grid Analysis ◽

Error Grid

Background: The accuracy of flash glucose monitoring (FGM, FreeStyle Libre Pro [FSL-Pro]) remains unclear in patients with type 2 diabetes mellitus (T2DM) undergoing hemodialysis. Methods: We assessed 13 patients with T2DM undergoing hemodialysis. They simultaneously underwent FGM, continuous glucose monitoring (CGM, iPro2), and self-monitoring blood glucose (SMBG). Results: Parkes error grid analysis against SMBG showed that 49.0% and 51.0% of interstitial fluid glucose (ISFG) levels measured using FGM and 93.3% and 6.7% of those measured using CGM fell into zones A and B, respectively. Mean absolute relative difference (MARD) against SMBG for FGM was significantly higher than that for CGM (19.5% ± 13.2% vs 8.1% ± 7.6%, P < .0001). Parkes error grid analysis of 2496 paired ISFG levels between FGM and CGM showed that 53.6%, 46.2%, and 0.2% of the plots fell into zones A, B, and C, respectively. Mean ISFG levels were lower with FGM than with CGM (143.7 ± 67.2 mg/dL vs 164.6 ± 58.5 mg/dL; P < .0001). Mean absolute relative difference of ISFG levels between FGM and CGM was 19.2% ± 13.8%. Among three groups classified according to CGM ISFG levels (hypoglycemia, <70 mg/dL; euglycemia, 70-180 mg/dL; and hyperglycemia, >180 mg/dL), the MARDs for hypoglycemia (31.9% ± 25.0%) and euglycemia (22.8% ± 14.6%) were significantly higher than MARD for hyperglycemia (13.0% ± 8.5%) ( P < .0001 in both). Conclusions: Flash glucose monitoring may be clinically acceptable. Average ISFG levels were lower with FGM than with CGM, and MARDs were higher for hypoglycemia and euglycemia in patients with T2DM undergoing hemodialysis.

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Accuracy and Stability of a Subcutaneous Flash Glucose Monitoring System in Critically Ill Patients

Journal of Diabetes Science and Technology ◽

10.1177/19322968211017203 ◽

2021 ◽

pp. 193229682110172

Author(s):

Hiromu Naraba ◽

Tadahiro Goto ◽

Mitsuhiro Tokuda ◽

Tomohiro Sonoo ◽

Hidehiko Nakano ◽

...

Keyword(s):

Critically Ill ◽

Critically Ill Patients ◽

Glucose Monitoring ◽

Blood Gas Analysis ◽

Relative Difference ◽

Gas Analysis ◽

Blood Gas ◽

Flash Glucose Monitoring ◽

Grid Analysis ◽

Error Grid

Background: Flash glucose monitoring (FGM) systems can reduce glycemic variability and facilitate blood glucose management within the target range. However, in critically ill patients, only small ( n < 30) studies have examined the accuracy of FGM and none have assessed the stability of FGM accuracy. We evaluated the accuracy and stability of FGM in critically ill patients. Method: This was a single-center, retrospective observational study. We included a total of 116 critically ill patients who underwent FGM for glycemic control. The accuracy of FGM was assessed as follows using blood gas glucose values as a reference: (1) numerical accuracy using the mean absolute relative difference, (2) clinical accuracy using consensus error grid analysis, and (3) stability of accuracy assessing 14-day trends in consensus error grid distribution. Results: FGM sensors remained in situ for a median of 6 [4, 11] days. We compared 2014 pairs of measurements between the sensor and blood gas analysis. Glucose values from the sensor were consistently lower, with a mean absolute relative difference of 13.8% (±16.0%), than those from blood gas analysis. Consensus error grid analysis demonstrated 99.4% of the readings to be in a clinically acceptable accuracy zone. The accuracy of FGM was stable across the 14 days after device insertion. Conclusions: FGM had acceptable reliability and accuracy to arterial blood gas analysis in critically ill patients. In addition, the accuracy of FGM persisted for at least 14 days. Our study promotes the potential usefulness of FGM for glycemic monitoring in critically ill patients.

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The Accuracy and Precision of the Continuously Stored Data from Flash Glucose Monitoring System in Type 2 Diabetes Patients during Standard Meal Tolerance Test

International Journal of Endocrinology ◽

10.1155/2020/5947680 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Rengna Yan ◽

Huiqin Li ◽

Xiaocen Kong ◽

Xiaofang Zhai ◽

Maoyuan Chen ◽

...

Keyword(s):

Type 2 Diabetes ◽

Glucose Monitoring ◽

Flash Glucose Monitoring ◽

Standard Meal ◽

Grid Analysis ◽

Sensor Glucose ◽

Interstitial Glucose ◽

Error Grid ◽

Diabetes Patients

Background. The purpose of this study was to investigate the accuracy of the continuously stored data from the Abbott FreeStyle Libre flash glucose monitoring (FGM) system in Chinese diabetes patients during standard meal tests when glucose concentrations were rapidly changing. Subjects and Methods. Interstitial glucose levels were monitored for 14 days in 26 insulin-treated patients with type 2 diabetes using the FGM system. Standard meal tests were conducted to induce large glucose swings. Venous blood glucose (VBG) was tested at 0, 30, 60, and 120 min after standard meal tests in one middle day of the first and second weeks, respectively. The corresponding sensor glucose values were obtained from interpolating continuously stored data points. Assessment of accuracy was according to recent consensus recommendations with median absolute relative difference (MARD) and Clarke and Parkes error grid analysis (CEG and PEG). Results. Among 208 paired sensor-reference values, 100% were falling within zones A and B of the Clarke and Parkes error grid analysis. The overall MARD was 10.7% (SD, 7.8%). Weighted least squares regression analysis resulted in high agreement between the FGM sensor glucose and VBG readings. The overall MTT results showed that FGM was lower than actual VBG, with MAD of 22.1 mg/dL (1.2 mmol/L). At VBG rates of change of -1 to 0, 0 to 1, 1 to 2, and 2 to 3 mg/dl/min, MARD results were 11.4% (SD, 8.7%), 9.4% (SD, 6.5%), 9.9% (SD, 7.5%), and 9.5% (SD, 7.7%). At rapidly changing VBG concentrations (>3 mg/dl/min), MARD increased to 19.0%, which was significantly higher than slow changing BG groups. Conclusions. Continuously stored interstitial glucose measurements with the FGM system were found to be acceptable to evaluate VBG in terms of clinical decision during standard meal tests. The continuously stored data from the FGM system appeared to underestimate venous glucose and performed less well during rapid glucose changes.

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Accuracy of Flash Glucose Monitoring in Patients with Diabetes Mellitus on Hemodialysis and Its Relationship with Hydration Status

Journal of Diabetes Science and Technology ◽

10.1177/1932296820975057 ◽

2020 ◽

pp. 193229682097505

Author(s):

Idoia Genua ◽

Joan Sánchez-Hernandez ◽

Maria José Martínez ◽

Isabel Pujol ◽

Jaume Places ◽

...

Keyword(s):

Diabetes Mellitus ◽

Patient Satisfaction ◽

Ad Hoc ◽

Glucose Monitoring ◽

Relative Difference ◽

Hydration Status ◽

Flash Glucose Monitoring ◽

Freestyle Libre ◽

Interstitial Glucose ◽

Capillary Glucose

Background: The use of flash-glucose monitoring system FreeStyle Libre (FSL) has demonstrated benefits in metabolic control and quality of life in different populations with diabetes mellitus (DM), being funded in many countries. Due to this, DM subjects on hemodialysis (HD) are using FSL despite the accuracy in this population being unclear. The aims of the present study are to assess the accuracy of FSL in DM subjects on HD, its relationship to hydration status, and patient satisfaction. Material and Methods: A prospective study in 16 patients with DM in a chronic HD program was conducted. Interstitial glucose values from FSL during a 14-day period were compared to capillary glucose measurements obtained at the same time. Hydration status was measured via bioimpedance spectroscopy. Satisfaction with FSL was obtained from an ad hoc satisfaction questionnaire. Results: A total of 766 paired interstitial and capillary glucose levels were analyzed. A correlation coefficient of 0.936 was determined and a mean absolute relative difference (MARD) value of 23%, increasing to 29% during HD. MARD was not related to hydration status. Interstitial glucose values were lower during HD (100.1 ± 17 mg/dL) than within the 12 hours after (125.1 ± 39 mg/dL; P = .012) and the days without HD (134.2 ± 32 mg/dL; P = .001). Subjects showed high satisfaction with FSL. Conclusion: The accuracy of FSL in DM patients on HD is lower than in other populations, especially during HD sessions and is not related with the hydration status. Despite this, the degree of patient satisfaction with FSL is very high.

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Accuracy of Dexcom G6 Continuous Glucose Monitoring in Non-Critically Ill Hospitalized Patients with Diabetes

10.2337/figshare.14454357.v1 ◽

2021 ◽

Author(s):

Georgia M. Davis ◽

Elias K. Spanakis ◽

Alexandra L. Migdal ◽

Lakshmi G. Singh ◽

Bonnie Albury ◽

...

Keyword(s):

Critically Ill ◽

Continuous Glucose Monitoring ◽

Diabetes Management ◽

Glucose Monitoring ◽

Relative Difference ◽

Hospitalized Patients ◽

Matched Pair ◽

Patients With Diabetes ◽

Clarke Error Grid ◽

Error Grid

Background: Advances in continuous glucose monitoring (CGM) have transformed ambulatory diabetes management. Until recently, inpatient use of CGM has remained investigational with limited data on its accuracy in the hospital setting. Methods: To analyze the accuracy of Dexcom G6 CGM, we compared retrospective matched-pair CGM and capillary point-of-care (POC) glucose data from three inpatient CGM studies (two interventional and one observational) in general medicine and surgery patients with diabetes treated with insulin. Analysis of accuracy metrics included mean absolute relative difference (MARD), median absolute relative difference (ARD), and proportion of CGM values within ±15, 20 and 30% or ±15, 20 and 30 mg/dL of POC reference values for blood glucose >100 mg/dL or ≤100 mg/dL, respectively (?/15, /20, 0/30). Clinical reliability was assessed using Clarke error grid analyses. Results: A total of 218 patients were included (96% with type 2 diabetes) with a mean age of 60.6 ± 12 years. The overall MARD (n=4,067 matched glucose pairs) was 12.8% and median ARD was 10.1% [IQR 4.6, 17.6]. The proportion of readings meeting ?/15, /20 and 0/30 criteria were 68.7, 81.7, and 93.8%. Clarke error grid analysis showed 98.7% of all values in zones A+B. MARD and median ARD were higher in hypoglycemia (<70mg/dL) and severe anemia (hemoglobin <7g/dL). Conclusion: Our results indicate that CGM technology is a reliable tool for hospital use and may help improve glucose monitoring in non-critically ill hospitalized patients with diabetes.

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Comparative Accuracy Analysis of a Real-time and an Intermittent-Scanning Continuous Glucose Monitoring System

Journal of Diabetes Science and Technology ◽

10.1177/1932296819895022 ◽

2019 ◽

pp. 193229681989502

Author(s):

Manuela Link ◽

Ulrike Kamecke ◽

Delia Waldenmaier ◽

Stefan Pleus ◽

Arturo Garcia ◽

...

Keyword(s):

Blood Glucose ◽

Real Time ◽

Continuous Glucose Monitoring ◽

Glucose Monitoring ◽

Relative Difference ◽

Comparison Method ◽

Freestyle Libre ◽

Glucose Meter ◽

Error Grid ◽

Blood Glucose Meter

Background: Currently, two different types of continuous glucose monitoring (CGM) systems are available: real time (rt) CGM systems that continuously provide glucose values and intermittent-scanning (is) CGM systems. This study compared accuracy of an rtCGM and an isCGM system when worn in parallel. Methods: Dexcom G5 Mobile (DG5) and FreeStyle Libre (FL) were worn in parallel by 27 subjects for 14 days including two clinic sessions with induced glucose excursions. The percentage of CGM values within ±20% or ±20 mg/dL of the laboratory comparison method results (YSI 2300 STAT Plus, YSI Inc., Yellow Springs, OH, United States; glucose oxidase based) or blood glucose meter values and mean absolute relative difference (MARD) were calculated. Consensus error grid and continuous glucose error grid analyses were performed to assess clinical accuracy. Results: Both systems displayed clinically accurate readings. Compared to laboratory comparison method results during clinic sessions, DG5 had 91.5% of values within ±20%/20 mg/dL and a MARD of 9.5%; FL had 82.5% of scanned values within ±20%/20 mg/dL and an MARD of 13.6%. Both systems showed a lower level of performance during the home phase and when using the blood glucose meter as reference. Conclusion: The two systems tested in this study represent two different principles of CGM. DG5 generally provided higher accordance with laboratory comparison method results than FL.

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A Multicenter Evaluation of the Performance and Usability of a Novel Glucose Monitoring System in Chinese Adults With Diabetes

Journal of Diabetes Science and Technology ◽

10.1177/1932296816662884 ◽

2016 ◽

Vol 11 (2) ◽

pp. 290-295 ◽

Cited By ~ 26

Author(s):

Linong Ji ◽

Xiaohui Guo ◽

Lixin Guo ◽

Qian Ren ◽

Nan Yu ◽

...

Keyword(s):

Glucose Monitoring ◽

Relative Difference ◽

Glucose Sensing ◽

Chinese Patients ◽

Chinese Adults ◽

Flash Glucose Monitoring ◽

Glucose Levels ◽

Patients With Diabetes ◽

Interstitial Glucose ◽

Error Grid

Objective: Flash glucose monitoring is a new glucose sensing technique that measures interstitial glucose levels for up to 14 days and does not require any calibration. The aim of this study is to evaluate the performance of the new system in Chinese patients with diabetes. Methods: A multicenter, prospective, masked study was performed in a total of 45 subjects with diabetes. Subjects wore 2 sensors at the same time, for up to 14 days. The accuracy was evaluated against capillary blood glucose (BG) and venous Yellow Springs Instrument (YSI; Yellow Springs, OH) measurements. During all 14 days, subjects were asked to perform at least 8 capillary BG tests per day. Each subject attended 3 days of 8-hour clinic sessions to measure YSI and sensor readings every 15 minutes. Results: Forty subjects had evaluable glucose readings, with 6687 of 6696 (99.9%) sensor and capillary BG pairs within consensus error grid zones A and B, including 5824 (87.0%) in zone A. The 6969 sensor and venous YSI pairs resulted in 6965 (99.9%) pairs within zones A and B, including 5755 (82.6%) in zone A. The sensor pairs with BG and YSI result in mean absolute relative difference (MARD) of 10.0% and 10.7%, respectively. Overall between-sensor coefficient of variation (CV) was 8.0%, and the mean lag time was 3.1 (95% confidence interval 2.54 to 4.29) minutes. Conclusions: The system works well for people with diabetes in China, and it is easy to wear and use.

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Use of continuous glucose monitoring system in patients with type 2 mellitus diabetic during hemodialysis treatment

Diabetology & Metabolic Syndrome ◽

10.1186/s13098-021-00722-8 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Marcelo Rocha Nasser Hissa ◽

Priscilla Nogueira Gomes Hissa ◽

Sérgio Botelho Guimarães ◽

Miguel Nasser Hissa

Keyword(s):

Continuous Glucose Monitoring ◽

Clinical Decision Making ◽

Glucose Monitoring ◽

Clinical Decision ◽

Relative Difference ◽

Fluid Loss ◽

Freestyle Libre ◽

Stage Renal Disease ◽

End Stage ◽

Error Grid

Abstract Background Studies highlight the inaccuracy of glycated hemoglobin (HbA1c) for the assessment of glycemic control in dialysis diabetics and suggest the use of continuous glucose monitoring (CGM) as an alternative. Of the CGMs, FreeStyle Libre® is the most used in worldwide, but there is still no consensus on its use in dialysis. Method A 3-week prospective study was performed with 12 patients comparing capillary and interstitial glucose during dialysis. Results Comparing capillary and interstitial measurements, similar values were observed in pre-dialysis in the 1st week (184.1 ± 69.5 mg/dl and 173.1 ± 78.9 mg/dl, respectively, p = 0.303), in patients with body mass index less than 24.9 kg/m2 (214.2 ± 72.2 mg/dl and 201.3 ± 77.0 mg/dl respectively, p = 0.466), in those dialysis fluid loss less than 2 l (185.5 ± 82.6 mg/dl and 183.1 ± 94.0 mg/dl respectively and p = 0.805) and in those with hemoglobin greater than 12 g/dl (152.0 ± 35, 5 mg/dl and 129.5 ± 47.4 mg/dl respectively, p = 0.016). In the correlation of the capillary measurement with the interstitial sensor, it was observed that the proportions in the Clarke Error Grid of zone A, zone B, zone C, zone D and zone E were 62.5%, 27.1%, 0.0%, 10.4% and 0.0% respectively and in the Parkes error grid in zone A, zone B, zone C, zone D and zone E were 80.6%, 9.7%, 9.7% 0.0% and 0.0%, respectively. Conclusion The mean absolute relative difference in dialysis patients is higher than the general population without end-stage renal disease. However, clinical decision-making based on the values measured by the system can be made with a good margin based on the correlation between interstitial and capillary measurements.

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Accuracy of CGM Systems During Continuous and Interval Exercise in Adults with Type 1 Diabetes

Journal of Diabetes Science and Technology ◽

10.1177/19322968211023522 ◽

2021 ◽

pp. 193229682110235

Author(s):

G. Da Prato ◽

S. Pasquini ◽

E. Rinaldi ◽

T. Lucianer ◽

S. Donà ◽

...

Keyword(s):

Glucose Monitoring ◽

Relative Difference ◽

Interval Exercise ◽

Sensor Glucose ◽

Interstitial Glucose ◽

Distribution Of Points ◽

Clarke Error Grid ◽

The Mean ◽

Error Grid

Background: continuous glucose monitoring systems (CGMs) play an important role in the management of T1D, but their accuracy may reduce during rapid glucose excursions. The aim of study was to assess the accuracy of recent rt-CGMs available in Italy, in subjects with T1D during 2 sessions of physical activity: moderate continuous (CON) and interval exercise (IE). Method: we recruited 22 patients with T1D, on CSII associated or integrated with a CGM, to which a second different sensor was applied. Data recorded by CGMs were compared with the corresponding plasma glucose (PG) values, measured every 5 minutes with the glucose analyzer. To assess the accuracy of the CGMs, we evaluated the Sensor Bias (SB), the Mean Absolute Relative Difference (MARD) and the Clarke error grid (CEG). Results: a total of 2355 plasma-sensor glucose paired points were collected. Both average plasma and interstitial glucose concentrations did not significantly differ during CON and IE. During CON: 1. PG change at the end of exercise was greater than during IE ( P = .034); 2. all sensors overestimated PG more than during IE, as shown by SB ( P < .001) and MARD ( P < .001) comparisons. Classifying the performance according to the CEG, significant differences were found between the 2 sessions in distribution of points in A and B zones. Conclusions: the exercise affects the accuracy of currently available CGMs, especially during CON, suggesting, in this circumstance, the need to maintain blood glucose in a “prudent” range, above that generally recommended. Further studies are needed to investigate additional types of activities.

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Comparison of the Freestyle Libre Pro Flash Continuous Glucose Monitoring (CGM) System and Point-of-Care Capillary Glucose Testing (POC) in Hospitalized Patients with Type 2 Diabetes (T2D) Treated with Basal-Bolus Insulin Regimen

10.2337/figshare.12302660.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Rodolfo J. Galindo ◽

Alexandra L. Migdal ◽

Georgia M. Davis ◽

Maria A. Urrutia ◽

Bonnie Albury ◽

...

Keyword(s):

Type 2 Diabetes ◽

Continuous Glucose Monitoring ◽

Point Of Care ◽

Glucose Monitoring ◽

Hospitalized Patients ◽

Glucose Testing ◽

Grid Analysis ◽

Freestyle Libre ◽

Error Grid

Background: We compared the performance of the FreeStyle Libre Pro continuous glucose monitoring (CGM) and point-of-care glucose testing among insulin-treated hospitalized patients with type 2 diabetes (T2D). Methods: Prospective study in general medicine and surgery adult patients with T2D. Patient were monitored with POC before meals and bedtime, and with CGM during the hospital stay. Major endpoints included differences between POC and CGM in mean daily blood glucose, hypoglycemia < 70 and < 54 mg/dl, and nocturnal hypoglycemia. We also calculated the mean absolute relative difference (MARD), and ±15%/15mg/dl, ±20%/20mg/dl, ± 30%/30mg/dl, and Error Grid analysis between matched glucose pairs. Results: Mean daily glucose was significantly higher by POC testing (188.9±37.3 vs. 176.1±46.9 mg/dl), and proportions of patients with glucoses < 70 mg/dl (14% vs 56%) and < 54 mg/dl (4.1% vs 36%) detected by POC BG were significantly lower compared to CGM, all p<0.001. Nocturnal and prolonged CGM hypoglycemia < 54 mg/dl was 26% and 12%, respectively. The overall MARD was 14.8%, ranging between 11.4 to 16.7% for glucoses between 70 and 250 mg/dl, and lower for 51- 69 mg/dL (MARD= 28.0%). The percentage of glucoses within the ±15%/15mg/dl, ±20%/20mg/dl, and ±30%/30mg/dl were 62%, 76%, and 91%, respectively. Error Grid analysis showed 98.0% of glucose pairs within Zones A and B. Conclusions: Compared to POC testing, FreeStyle Libre CGM showed lower mean daily glucose and higher detection of hypoglycemic events, particularly nocturnal and prolonged hypoglycemia in hospitalized patients with T2D. CGM’s accuracy was lower in hypoglycemic range.

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