Continuous glucose monitoring system: Is it really accurate, safe and clinically useful?

Pre-cooling with ingesting a high-carbohydrate ice slurry on thermoregulatory responses and subcutaneous interstitial fluid glucose during heat exposure

The purpose of this study was to compare the effects of ingesting ice slurries with two different carbohydrate contents on body temperatures and the subcutaneous interstitial fluid glucose level during heat exposure. Seven physically active men underwent one of three interventions: the ingestion of 7.5 g/kg of a control beverage (CON: 26°C), a normal-carbohydrate ice slurry (NCIS: −1°C), or a high-carbohydrate ice slurry (HCIS: −5°C). The participants were monitored for a 120-min period that included 10 min of rest, 25 min of exposure to the experimental cooling intervention (during which the beverage was ingested), and 85 min of seated rest in a climate chamber (36°C, 50% relative humidity). The rectal temperature in the HCIS and NCIS trials was lower than that in the CON trial from 40 to 75 min. The infrared tympanic temperature was also lower in the HCIS and NCIS trials than in the CON trial from 20 to 50 min, whereas the deep thigh or mean skin temperatures were not significantly different among the three groups. From 90 to 120 min, the subcutaneous interstitial fluid glucose level in the NCIS trial was lower than that at 65 min; however, reductions were not seen in the HCIS and CON trials. These findings suggest that both HCIS ingestion and conventional NCIS ingestion were effective cooling strategies for reducing thermal strain, while HCIS ingestion may also enable a higher subcutaneous interstitial fluid glucose level to be maintained, ensuring an adequate supply of required muscle substrates.

Association of time in range with hemoglobin A1c, glycated albumin and 1,5-anhydro-d-glucitol

AIMS/INTRODUCTION

Hemoglobin A1c (HbA1c), glycated albumin (GA) and 1,5-anhydro-d-glucitol (1,5-AG) are used as indicators of glycemic control, whereas continuous glucose monitoring (CGM) is used to assess daily glucose profiles. The aim of this study was to investigate the relationships between CGM metrics, such as time in range (TIR), and glycemic control indicators.

MATERIALS AND METHODS

We carried out retrospective CGM and blood tests on 189 outpatients with impaired glucose tolerance (n = 22), type 1 diabetes mellitus (n = 67) or type 2 diabetes mellitus (n = 100).

RESULTS

In type 1 diabetes mellitus and type 2 diabetes mellitus patients, HbA1c and GA were negatively correlated with TIR, whereas 1,5-AG was positively correlated with TIR. In type 1 diabetes mellitus patients, a TIR of 70% corresponded to HbA1c, GA and 1,5-AG of 6.9% (95% confidence interval [CI] 6.5-7.2%), 20.3% (95% CI 19.0-21.7%) and 6.0 µg/mL (95% CI 5.1-6.9 µg/mL), respectively. In type 2 diabetes mellitus patients, a TIR of 70% corresponded to HbA1c, GA and 1,5-AG of 7.1% (95% CI 7.0-7.3%), 19.3% (95% CI 18.7-19.9%) and 10.0 µg/mL (95% CI 9.0-11.0 µg/mL), respectively. TIR values corresponding to HbA1c levels of 7.0% were 56.1% (95% CI 52.3-59.8%) and 74.2% (95% CI 71.3-77.2%) in type 1 diabetes mellitus and type 2 diabetes mellitus patients, respectively.

CONCLUSIONS

The results of this study showed that the estimated HbA1c corresponding to a TIR of 70% was approximately 7.0% for both type 1 diabetes mellitus and type 2 diabetes mellitus patients, and that the estimated 1,5-AG calculated from the TIR of 70% might be different between type 1 diabetes mellitus and type 2 diabetes mellitus patients.

Continuous Glucose Monitoring in Patients With Insulinoma Treated by Endoscopic Ultrasound-Guided Ethanol Injection

OBJECTIVES

The aims of this study were to analyze the continuous glucose monitoring (CGM) profiles of patients with insulinoma before and after treatment with endoscopic ultrasound-guided ethanol injection and assess the value of CGM in curative effect evaluating.

METHODS

We included 8 patients, and CGM was performed for 3 to 5 days before and after treatment.

RESULTS

The proportion of monitoring points at which the glucose level was lower than 3.9 mmol/L after treatment decreased in patient 5 (from 4% to 3%) and patient 8 (from 30% to 12%), whereas the proportion increased in patient 1 (from 1% to 16%), patient 3 (from 5% to 23%), and patient 7 (from 7% to 63%). There was no mean significant difference between CGM values (5.75 [standard deviation, 2.49] mmol/L) and self-monitoring of blood glucose values (5.76 [standard deviation, 2.32] mmol/L) (P > 0.05). Pearson correlation analysis showed positive correlation between CGM values and self-monitoring of blood glucose values (r = 0.88, P < 0.05). Clarke Error Grid Analysis showed that 91.5% of pairs were located in areas A and B.

CONCLUSIONS

Continuous glucose monitoring is useful for detecting hypoglycemia and evaluating curative effect, but the correction of fingertip blood glucose is necessary when the blood glucose is relatively low.

Careful readings for a flash glucose monitoring system in nondiabetic Japanese subjects: individual differences and discrepancy in glucose concentrarion after glucose loading [Rapid Communication]

The FreeStyle Libre Flash Glucose Monitoring System (FGM), which can continuously measure glucose concentration in the interstitial fluid glucose (FGM-ISFG), has been in clinical use worldwide. However, it is not clear how accurately FGM-ISFG reflects plasma glucose concentration (PG). In the present study, we examined the clinical utility of FGM by oral glucose tolerance test (OGTT). In eight healthy volunteers (3 males; mean age, 41.8 y) wearing FGM sensors for 14 days, OGTT was performed during days 1-7 and days 8-14, and then both FGM-ISFG and PG were compared. Parkes error grid analysis indicated that all of 65 FGM-ISFG values were within Zone A (no effect on clinical action) and Zone B (little or no effect on clinical outcome). However, in OGTT, the mean FGM-ISFG was higher than the mean actual PG at 30, 60, and 90 minutes after loading (155.5 vs. 139.2 mg/dL, 166.2 vs. 139.2 mg/dL, 149.5 vs. 138.2 mg/dL, respectively; p<0.05). Moreover, the area under the curve of FGM-ISFG was also significantly larger than that of PG (17,626.2 vs. 15,195.0 min·mg/dL; p<0.05). In four of eight subjects, FGM-ISFG tended to be higher than PG in both OGTTs, and the greatest difference between the two values was 58 mg/dL. FGM is useful for glycemic control, whereas it is not appropriate to change therapeutic regimens based on the judgment of nocturnal hypoglycemia and postprandial hyperglycemia by FGM-ISFG. Careful attention is required for proper application of FGM.

Effect of treatment guidance using a retrospective continuous glucose monitoring system on glycaemic control in outpatients with type 2 diabetes mellitus: A randomized controlled trial

Objectives

To assess the effect of treatment guidance based on data from a continuous glucose monitoring (CGM) device on glycaemic control, and patient satisfaction, in patients with type 2 diabetes mellitus (T2DM).

Methods

Patients with poorly-controlled T2DM treated with insulin were randomly assigned to the intervention or nonintervention group. Continuous blood-glucose levels were recorded for 4–5 days using a CGM device on three separate occasions during the 8-month study period. The intervention group received treatment guidance based on the CGM data; the nonintervention group received advice based on blood glucose and glycosylated haemoglobin (HbA_1c) levels.

Results

A total of 34 patients were enrolled in the study. The mean ± SD baseline HbA_1c was 8.2 ± 1.2% in the intervention group and 8.2 ± 0.9% in the nonintervention group. At the study end, there was no significant difference in the change from baseline of HbA_1c between the two groups. There was also no significant difference in the change from baseline in the Diabetes Treatment Satisfaction Questionnaire score between the two groups.

Conclusions

The present study did not demonstrate that treatment guidance using retrospective CGM data was effective for improving glycaemic control and therapeutic satisfaction in Japanese patients with T2DM.