Can interstitial glucose assessment replace blood glucose measurements?

Current treatment regiments for individuals depending on exogenous insulin are based on measurements of blood glucose obtained through painful finger sticks. The shift to minimal or noninvasive continuous glucose monitoring primarily involves a shift from blood glucose measurements to devices measuring subcutaneous interstitial fluid (ISF) glucose. As the development of these devices progresses, details of the dynamic relationship between blood glucose and interstitial glucose dynamics need to be firmly established. This is a challenging task insofar as direct measures of ISF glucose are not readily available. The current article investigated the dynamic relationship between plasma and ISF glucose using a model-based approach. A two-compartment model system previously validated on data obtained with the MiniMed Continuous Glucose Monitoring System (CGMS) is reviewed and predictions from the original two-compartment model were confirmed using new data analysis of glucose dynamics in plasma and hindlimb lymph (lymph is derived from ISF) in the anesthetized dog. From these data sets, the time delay between plasma and ISF glucose in dogs was established (5-12 minutes) and a simulation study was performed to estimate the errors introduced if ISF is taken as a surrogate for blood. From the simulation study, the error component resulting from the differences in plasma and ISF glucose was estimated to be < 6% during normal day-to-day use in an individual with diabetes (error component calculated as the standard deviation of the ISF/plasma glucose differences under conditions where the maximal time delay was used). This difference is most likely within the variance between arterial and venous blood glucose. We conclude that the differences between plasma and ISF glucose will not be a significant obstacle in advancing the use of ISF as an alternative to blood glucose measurements.     

Analysis of the Nova Stat Strip® glucose meter for real-time blood glucose determinations during glucose clamp studies: "don't swap horses in midstream"

Proper performance of glucose clamps is critically dependent on reliable blood glucose (BG) measurements. A number of requirements have to be fulfilled by a system that aims to replace the laboratory devices that are currently in use. Many more aspects need to be taken into account besides the accuracy of BG measurement. It might very well be that the BG meter studied by Rabiee and colleagues in this issue of Journal of Diabetes Science and Technology fulfills most or all of such requirements; however, these aspects have to be tested more thoroughly before one switches from an established measurement method to the Nova Stat Strip® glucometer.     

Can dietary fructans lower serum glucose?

Background: Convincing evidence indicates that the consumption of inulin‐type fructans, inulin, and oligofructose has beneficial effects on blood glucose changes in animal models, although data in humans have been considered equivocal. As such, a systematic review of available literature on humans was conducted to evaluate the effectiveness of dietary inulin‐type fructans on serum glucose. Methods: Thirteen eligible randomized controlled trials (RCT), published from 1984 to 2009, were identified using a comprehensive search strategy involving the PubMed, Medline, and Cochrane Library databases. Exclusion criteria, such as the absence of a control group, lack of information on the quantity of inulin‐type fructans used, and lack of glucose values at outcome, were established. Results: Upon review, only four of the 13 trials (31%) showed a decrease in serum glucose concentration and only one of these was statistically significant. The remaining nine trials showed no significant changes in serum glucose concentration. Conclusion: Based on the present systematic review, it does not appear that inulin‐type fructans have a significant lowering effect on serum glucose in humans. More RCT are needed to determine whether inulin‐type fructans, inulin, and oligofructose have beneficial effects on blood glucose in humans.     

Better blood glucose? You bet!

Good blood glucose control can seem like a lofty goal. But if you take it one step at a time, you can achieve it. Here, the experts show you how.     

Can either oral glucose challenge test or oral glucose tolerance test parameters predict gestational diabetes mellitus?

This study aims to evaluate the relationship between the glucose challenge test (GCT) levels and any of the oral glucose tolerance test (OGTT) parameters (fasting plasma glucose (FPG), 1-, 2-, or 3-h plasma glucose levels) and their effect on predicting gestational diabetes mellitus (GDM). This analysis was carried out as a retrospective study at Obstetrics and Gynecology Clinic of Turgut Özal University Hospital. Oral GCT were conducted on patients who are at 24–29 weeks’ gestation. The study participants with positive GCT results underwent a 3-h, 100-g OGTT, and the resulting values were evaluated using Carpenter and Coustan diagnostic criteria to determine the gestational glucose tolerance status of patients. The data obtained from both tests (GCT, FPG, 1-, 2-, 3-h OGTT values) were analyzed to observe the effect of each group on predicting GDM. Although all of the GCT and OGTT values were found to be statistically significant (p?<?0.001) in determining GDM, the 2-h values of OGTT detected almost all GDM cases with a very high sensitivity level (94.5 %). The 1-h values on the other hand identified 87.6 % of GDM (p?<?0.001). The GCT value with the highest sensitivity and specificity for predicting GDM was calculated as 154.50 mg/dl (sensitivity and specificity rates were 79.2 and 72.8 %, respectively). A 2-h OGTT glucose level can detect GDM with 94.5 % sensitivity. This result can guide clinicians to evaluate the patients with GDM.     

Sodium–glucose cotransporter 2 inhibitors reduce day-to-day glucose variability in patients with type 1 diabetes

Aims/IntroductionSodium–glucose cotransporter 2 inhibitors (SGLT2i) are used worldwide because of their multiple benefits for patients with type 2 diabetes. The purpose of this study was to determine the efficacy and safety of SGLT2i in patients with type 1 diabetes.Materials and MethodsPatients with type 1 diabetes who had been treated with SGLT2i for >12 weeks were included in this retrospective observation study. We recorded the changes in body mass, insulin dose, blood and urine test data, and adverse events. The changes in day‐to‐day glucose variability, as the primary end‐point, was evaluated using the interquartile range (P25/P75) of the ambulatory glucose data obtained using continuous glucose monitoring.ResultsA total of 51 patients (37 women; mean age 52.7 years) were included. Glycated hemoglobin and body mass significantly decreased by 0.4% and 1.6 kg, respectively. The total required insulin dose decreased by 9.4% (42.7 ± 26.6–38.7 ± 24.3 units/day). Continuous glucose monitoring data were obtained from 30 patients. P25/P75 decreased by 17.6 ± 20.7% during SGLT2i treatment (P < 0.001). The percentage of time per day within the target glucose range of 70–180 mg/dL significantly increased (from 42.2 to 55.5%, P < 0.001), without an increase in the percentage of time spent in the hypoglycemic range (<70 mg/dL). Urinary ketone bodies were detected in four patients (7.8%), but none developed ketoacidosis.ConclusionsSGLT2i improved day‐to‐day glucose variability and time in the target glucose range, without increasing frequency of hypoglycemia, in patients with type 1 diabetes, and reduced glycated hemoglobin, body mass and the required insulin dose.     

Can plasma glucose and HbA1c predict fetal growth in mothers with different glucose tolerance levels?

To assess whether HbA1c and plasma glucose predicts abnormal fetal growth, 758 pregnant women attending 5 Diabetic Centers were screened for gestational diabetes mellitus (GDM). On glucose challenge (GCT) at 24-27 weeks of gestation (g.w.), negative cases formed the normal control group (N1). Positive cases took an oral glucose tolerance test (OGTT): those found negative were classed as false positives screening test (N2); if they had an OGTT result at least as high as their normal glucose levels, they were classed as having one abnormal glucose value (OAV) at OGTT; two values as GDM. HbA1c was assayed on the day of GCT. We considered fetal macrosomia, large for gestational age (LGA), ponderal index and mean growth percentile. Mean age, pre-pregnancy BMI, fasting plasma glucose (FPG) and HbA1c were progressively higher from N1 to GDM patients. The newborn of N2 mothers were heavier than those with N1 or GDM. The mean growth percentile was significantly higher in N2 than in N1. More LGA babies were born to OAV than to N1 or N2 women. Macrosomia and ponderal index did not differ significantly in the four groups. At logistic regression only plasma glucose at GCT could predict LGA babies and a ponderal index above 2.85. At risk analysis, GDM and OAV significantly predicted LGA babies, and GDM a ponderal index >2.85. In conclusion, FPG at GCT could predict fetal overgrowth and plasma glucose >85mg/dl doubles the risk of LGA infants. HbA1c at 24-27g.w. does not predict fetal overgrowth. Mild alterations in glucose tolerance correlate with fetal overgrowth and needs monitoring and treatment.     

Can targeting ANGPTL proteins improve glucose tolerance?

Three members of the angiopoietin-like (ANGPTL) family of proteins, ANGPTL3, ANGPTL4 and ANGPTL8, are known regulators of plasma triacylglycerol levels. Recently, these three proteins have garnered considerable interest as potential targets for therapeutically reducing plasma triacylglycerol levels and improving cardiovascular outcomes. In this issue of Diabetologia, Janssen et al ( https://doi.org/10.1007/s00125-018-4583-5) and Vatner et al ( https://doi.org/10.1007/s00125-018-4579-1) show that reducing levels of ANGPTL4 and ANGPTL8, respectively, could have the added benefit of improving glucose tolerance. Interestingly, the improvements in glucose tolerance observed in both studies, both done in rodents, were coupled with increased fat mass. These findings suggest that funnelling lipids to adipose tissue and away from ectopic sites could be beneficial and strengthen the argument for pursuing the therapeutic targeting of ANGPTL proteins.     

Continuous glucose monitoring: coming of age?

In a recent issue of the Journal of Clinical Endocrinology and Metabolism, an Endocrine Society Clinical Practice Guideline on Continuous Glucose Monitoring (CGM) was published, co-sponsored by the European Society of Endocrinology. Such a guideline is a necessary step in the maturation of any new technology. This commentary tries to delineate where we stand some 10 years after the first retrospective CGM device entered the market from a European perspective.     

Is fasting glucose level during oral glucose tolerance test an indicator of the insulin need in gestational diabetes?

Maintenance of a good metabolic control improves foetal and maternal outcomes in gestational diabetes mellitus (GDM). The aim of this study is to investigate the utility of diagnostic oral glucose tolerance test (OGTT) in prediction of the need of insulin in patients with GDM. One hundred and fifty five consecutive patients with GDM were included in the study. Patients were ordered MNT first. Those who failed to maintain glycemic targets were treated with insulin. Glucose levels obtained from the diagnostic OGTT were evaluated regarding the need of insulin during the rest of pregnancy. Fasting, 1h and 3h post-load glucose levels were significantly elevated in patients who required insulin. Multivariate analysis showed that fasting glucose level on OGTT was an independent predictor for the insulin need. A cut-off value of 105mg/dl had a fair specificity (91.89%) and positive predictive value (80.64%) for the prediction of patients who required insulin during the rest of their pregnancy. Our results suggest that fasting glucose level on OGTT is a predictor of the need for insulin treatment in GDM. A cut-off level of 105mg/dl seems to effectively determine high-risk patients for additional treatment other than MNT in GDM.     

A higher-carbohydrate, lower-fat diet reduces fasting glucose concentration and improves β-cell function in individuals with impaired fasting glucose

The objective was to examine the effects of diet macronutrient composition on insulin sensitivity, fasting glucose, and β-cell response to glucose. Participants were 42 normal glucose-tolerant (NGT; fasting glucose <100 mg/dL) and 27 impaired fasting glucose (IFG), healthy, overweight/obese (body mass index, 32.5 ± 4.2 kg/m(2)) men and women. For 8 weeks, participants were provided with eucaloric diets, either higher carbohydrate/lower fat (55% carbohydrate, 18% protein, 27% fat) or lower carbohydrate/higher fat (43:18:39). Insulin sensitivity and β-cell response to glucose (basal, dynamic [PhiD], and static) were calculated by mathematical modeling using glucose, insulin, and C-peptide data obtained during a liquid meal tolerance test. After 8 weeks, NGT on the higher-carbohydrate/lower-fat diet had higher insulin sensitivity than NGT on the lower-carbohydrate/higher fat diet; this pattern was not observed among IFG. After 8 weeks, IFG on the higher-carbohydrate/lower-fat diet had lower fasting glucose and higher PhiD than IFG on the lower-carbohydrate/higher-fat diet; this pattern was not observed among NGT. Within IFG, fasting glucose at baseline and the change in fasting glucose over the intervention were inversely associated with baseline PhiD (-0.40, P < .05) and the change in PhiD (-0.42, P < .05), respectively. Eight weeks of a higher-carbohydrate/lower-fat diet resulted in higher insulin sensitivity in healthy, NGT, overweight/obese individuals, and lower fasting glucose and greater glucose-stimulated insulin secretion in individuals with IFG. If confirmed, these results may have an impact on dietary recommendations for overweight individuals with and without IFG.