Assessment of factors associated with improved glycemic control after switching from intermittently scanned to real-time continuous glucose monitoring in Japanese patients with type 1 diabetes.

The advantages of real-time continuous glucose monitoring (rtCGM) over intermittently scanned CGM (isCGM) reportedly include lower glycated hemoglobin (HbA1c) levels as well as reduced glycemic variability. However, there have been few studies of the effect of switching from isCGM to rtCGM on glycemic control, as well as the specific factors underlying any observed improvements. To that end, all patients with type 1 diabetes mellitus who used the DEXCOM rtCGM device (Terumo Corporation, Tokyo, Japan) at our institution were reviewed, and 16 individuals with type 1 diabetes who switched from isCGM to rtCGM were investigated. The patients' HbA1c decreased in 75% of the cases (p = 0.02). On the other hand, GMI increased in 75% of the cases (p = 0.01). Intriguingly, the percentage of time below range and coefficient of variation were significantly improved with rtCGM compared to isCGM (2.9% vs. 7.6%, p = 0.016 and 35% vs. 40%, p = 0.0019, respectively). We also found that the discrepancy between HbA1c and GMI among users of isCGM was a key indicator that improved when switching to rtCGM. If discrepancies are observed between HbA1c and GMI when using isCGM, switching to rtCGM should be considered for improving glycemic control.

Assessment of factors that determine the mean absolute relative difference in flash glucose monitoring with reference to plasma glucose levels in Japanese subjects without diabetes.

The Abbott FreeStyle Libre flash glucose monitoring system (FGM) is a recently introduced, but widespread continuous glucose monitoring system. While its mean absolute relative difference (MARD) value indicating its accuracy is acceptable with reference to the self-monitoring of blood glucose (SMBG) levels, few reports have examined the MARD in sensor glucose values of FGM (FGM-SG) with reference to plasma glucose (PG) levels and the factors determining it. We performed oral glucose tolerance tests (OGTTs) in 25 Japanese subjects without diabetes. Parkes error grid analyses showed that FGM-SG with either SMBG or PG levels as a reference met International Organization for Standardization criteria. The MARD in FGM-SG with reference to SMBG levels was 10.9 ± 4.1% during OGTTs. Surprisingly, the MARD in FGM-SG with reference to PG levels was 20.3 ± 10.3% during OGTTs, revealing a discrepancy in the accuracy of FGM-SG compared with that of PG levels; moreover, the MARD showed negative correlations with fasting blood sugar level, homeostasis model assessment insulin resistance index, and body mass index (BMI). Multiple regression analyses revealed that BMI contributed the most to the MARD when FGM-SG and PG level were compared, as lean individuals have a greater MARD regardless of glucose levels. Inaccurate FGM data could potentially increase the risk of inappropriate treatment; consideration of such factors is critical to ensure reliable FGM values.

Assessment of factors determining an HbA1c concentration ≤7.5% in patients with type 1 diabetes.

BACKGROUND: Establishing an optimal insulin regimen is crucial for maintaining glycemic control in patients with type 1 diabetes (T1D). The aim of the present study was to determine the insulin dose required to achieve an HbA1c concentration ≤7.5% in Japanese patients with T1D. METHODS: The present multicenter cross-sectional study was performed at three institutes in Japan. Information was collected regarding patient age, sex, body weight, body mass index (BMI), HbA1c, total daily insulin dose (TDD), and total basal insulin dose (TBD), and the effects of these factors on achieving HbA1c ≤7.5% were investigated. RESULTS: Of 107 patients with T1D, 92 had no detectable endogenous insulin secretion: 39 had HbA1c ≤7.5% (well-controlled group) and 53 had HbA1c >7.5% (poorly controlled group). No significant differences in age, sex, height, body weight, BMI, diabetes duration, stage of diabetic kidney disease, treatment, or TDD were noted between the poorly and well-controlled groups. The TBD as a percentage of TDD (%TBD) was lower in patients with well-controlled diabetes ( P < 0.05) after adjustment for age, gender, and diabetes duration. In the well-controlled group, TDD was correlated with body weight ( R = 0.51), BMI ( R = 0.44), body surface area ( R = 0.41), and TBD ( R = 0.73; P < 0.01 for all), but TBD was not correlated with BMI or body surface area. In our population, a %TBD of approximately 30% was appropriate, without considering BMI. CONCLUSIONS: To achieve HbA1c ≤7.5 in patients with T1D, TDD should be calculated based on body weight, and the %TBD should be set at 30% in the Japanese population.

HBA1C AND MEAN GLUCOSE DERIVED FROM SHORT-TERM CONTINUOUS GLUCOSE MONITORING ASSESSMENT DO NOT CORRELATE IN PATIENTS WITH HBA1C >8.

OBJECTIVE: Optimum therapy for patients with diabetes depends on both acute and long-term changes in plasma glucose, generally assessed by glycated hemoglobin (HbA1c) levels. However, the correlation between HbA1c and circulating glucose has not been fully determined. Therefore, we carefully examined this correlation when glucose levels were assessed by continuous glucose monitoring (CGM). METHODS: Fifty-one patients (70% female, 30% male) were examined; among them were 28 with type 1 diabetes and 23 with type 2 diabetes. Clinically determined HbA1c levels were compared with blood glucose determined by CGM during a short time period. RESULTS: Changes in HbA1c levels up to 8.0% showed a clear and statistically strong correlation (R = 0.6713; P<.0001) with mean blood glucose levels measured by CGM, similar to that observed in the A1c-derived Average Glucose study in which patients were monitored for a longer period. However, we found no statistical correlation (R = 0.0498; P = .83) between HbA1c and CGM-assessed glucose levels in our patient population when HbA1c was >8.0%. CONCLUSION: Short-term CGM appears to be a good clinical indicator of long-term glucose control (HbA1c levels); however, cautions should be taken while interpreting CGM data from patients with HbA1c levels >8.0%. Over- or underestimation of the actual mean glucose from CGM data could potentially increase the risks of inappropriate treatment. As such, our results indicate that a more accurate analysis of CGM data might be useful to adequately tailor clinical treatments. ABBREVIATIONS: ADAG = A1c-Derived Average Glucose CGM = continuous glucose monitoring %CV = percent coefficient of variation HbA1c = glycated hemoglobin.

Fyn-dependent regulation of energy expenditure and body weight is mediated by tyrosine phosphorylation of LKB1.

Fyn null mice display reduced adiposity associated with increased fatty acid oxidation, energy expenditure, and activation of the AMP-dependent protein kinase (AMPK) in skeletal muscle and adipose tissue. The acute pharmacological inhibition of Fyn kinase activity with SU6656 in wild-type mice reproduces these metabolic effects and induced a specific reduction in fat mass with no change in lean mass. LKB1, the main upstream AMPK kinase (AMPKK) in peripheral tissues, was redistributed from the nucleus into the cytoplasm of cells treated with SU6656 and in cells expressing a kinase-deficient, but not a constitutively kinase-active, Fyn mutant. Moreover, Fyn kinase directly phosphorylated LKB1 on tyrosine 261 and 365 residues, and mutations of these sites resulted in LKB1 export into the cytoplasm and increased AMPK phosphorylation. These data demonstrate a crosstalk between Fyn tyrosine kinase and the AMPK energy-sensing pathway, through Fyn-dependent regulation of the AMPK upstream activator LKB1.