Effects of Continuous Carbohydrate Intake with Gummies during the Golf Round on Interstitial Glucose, Golf Performance, and Cognitive Performance of Competitive Golfers: A Randomized Repeated-Measures Crossover Design

This study examined the effects of continuous carbohydrate intake during a golf round on interstitial glucose, golf performance, and the cognitive performance of competitive golfers. Eleven competitive golfers participated and played 18 holes of golf in this study. Participants were randomly assigned to the group indicated to consume the test food (CHO intake) or the group required to not consume it (NOT intake). Here, gummies were used as the test food, and the amount of carbohydrates was 30 g per h. Blood glucose levels were evaluated using interstitial glucose. Golf performance was measured in five tests, including scores, 2.5 m putting test, club head speed, driving distance, and accuracy. Cognitive performance was measured in three tests, including self-perceived levels of fatigue (PLF), self-perceived levels of concentration (PLC), and self-perceived levels of relaxation (PLR). Interstitial glucose (p < 0.001) and PLF (p < 0.001) were significantly reduced in the CHO intake compared with that in the NOT intake from the sixth hole. PLC was significantly higher in the CHO intake than in the NOT intake on all 18 holes (p = 0.032). These findings suggest that continuous carbohydrate intake may be effective in reducing fatigue and maintaining the performance of competitive golfers.

Performance of the FreeStyle Libre Flash Glucose Monitoring System during an Oral Glucose Tolerance Test and Exercise in Healthy Adolescents

This study's aim was to assess FreeStyle Libre Flash glucose monitoring (FGM) performance during an oral glucose tolerance test (OGTT) and treadmill exercise in healthy adolescents. This should advance the feasibility and utility of user-friendly technologies for metabolic assessments in adolescents. Seventeen healthy adolescents (nine girls aged 12.8 ± 0.9 years) performed an OGTT and submaximal and maximal treadmill exercise tests in a laboratory setting. The scanned interstitial fluid glucose concentration ([ISFG]) obtained by FGM was compared against finger-prick capillary plasma glucose concentration ([CPG]) at 0 (pre-OGTT), -15, -30, -60, -120 min post-OGTT, pre-, mid-, post- submaximal exercise, and pre- and post- maximal exercise. Overall mean absolute relative difference (MARD) was 13.1 ± 8.5%, and 68% (n = 113) of the paired glucose data met the ISO 15197:2013 criteria. For clinical accuracy, 84% and 16% of FGM readings were within zones A and B in the Consensus Error Grid (CEG), respectively, which met the ISO 15197:2013 criteria of having at least 99% of results within these zones. Scanned [ISFG] were statistically lower than [CPG] at 15 (-1.16 mmol∙L^-1, p < 0.001) and 30 min (-0.74 mmol∙L^-1, p = 0.041) post-OGTT. Yet, post-OGTT glycaemic responses assessed by total and incremental areas under the curve (AUCs) were not significantly different, with trivial to small effect sizes (p ≥ 0.084, d = 0.14-0.45). Further, [ISFGs] were not different from [CPGs] during submaximal and maximal exercise tests (interaction p ≥ 0.614). FGM can be a feasible alternative to reflect postprandial glycaemia (AUCs) in healthy adolescents who may not endure repeated finger pricks.

The Use of Continuous Glucose Monitors in Sport: Possible Applications and Considerations

This review discusses the potential value of tracking interstitial glucose with continuous glucose monitors (CGMs) in athletes, highlighting possible applications and important considerations in the collection and interpretation of interstitial glucose data. CGMs are sensors that provide real time, longitudinal tracking of interstitial glucose with a range of commercial monitors currently available. Recent advancements in CGM technology have led to the development of athlete-specific devices targeting glucose monitoring in sport. Although largely untested, the capacity of CGMs to capture the duration, magnitude, and frequency of interstitial glucose fluctuations every 1-15 min may present a unique opportunity to monitor fueling adequacy around competitive events and training sessions, with applications for applied research and sports nutrition practice. Indeed, manufacturers of athlete-specific devices market these products as a "fueling gauge," enabling athletes to "push their limits longer and get bigger gains." However, as glucose homeostasis is a complex phenomenon, extensive research is required to ascertain whether systemic glucose availability (estimated by CGM-derived interstitial glucose) has any meaning in relation to the intended purposes in sport. Whether CGMs will provide reliable and accurate information and enhance sports nutrition knowledge and practice is currently untested. Caveats around the use of CGMs include technical issues (dislodging of sensors during periods of surveillance, loss of data due to synchronization issues), practical issues (potential bans on their use in some sporting scenarios, expense), and challenges to the underpinning principles of data interpretation, which highlight the role of sports nutrition professionals to provide context and interpretation.

Diabetes: the role of continuous glucose monitoring

Diabetes mellitus is a chronic condition affecting 1 out of every 11 people worldwide. Monitoring of blood glucose allows for therapeutic lifestyle and pharmacotherapy changes to reduce the occurrence of hyperglycaemia and hypoglycaemia. Advancements in technology over the past two decades have increased patient and clinician access to glucose data and trends with continuous glucose monitoring (CGM) systems. This narrative review seeks to investigate the efficacy and safety of CGM for the management of diabetes. In type 1 diabetes (T1DM) and type 2 diabetes, efficacy studies of real-time CGM (rtCGM) or intermittently scanned CGM (isCGM) have shown a decrease in HbA1C (0.3–0.6%) over traditional self-monitoring blood glucose. Percent time in the target glucose range also improved (6.8–17.6%). Rates of hypoglycaemia, including severe hypoglycaemia, decreased in studies of rtCGM and isCGM with most available data in T1DM. In pregnant women with T1DM, rtCGM has shown modest improvements in HbA1C and time in target glucose range and decreased risk of neonatal complications. Multiple studies have shown that the use of rtCGM or isCGM increased diabetes treatment satisfaction amongst patients. Head-to-head studies of rtCGM and isCGM are limited but one study indicates that a CGM system with alarms may be preferred in T1DM to reduce the risk of hypoglycaemia. Selection of a CGM device should depend on patient-specific factors and insurance coverage. The results of one study show that the benefits of CGM device use were not sustained after discontinuing use. Increasing widespread and long-term access to CGM devices is necessary to improve the management of diabetes amongst the greater population.

Evaluation of the FreeStyle Libre, a flash glucose monitoring system, in client-owned cats with diabetes mellitus

Objectives

Home blood glucose monitoring using a portable blood glucose meter is important in the management of feline diabetes mellitus, but taking blood samples may be stressful for owners and cats. A flash glucose monitoring system measuring interstitial glucose, such as the FreeStyle Libre, overcomes some of these drawbacks. The aim of this study was to evaluate the practical use and analytical and clinical accuracy of the FreeStyle Libre in 41 client-owned diabetic cats.

Methods

In this prospective study, interstitial glucose concentrations were measured with the FreeStyle Libre and compared with blood glucose concentrations measured with a portable blood glucose meter (AlphaTRAK) on days 1, 7 or 8 and 14 after application of the device. Cat behaviour during application, location, skin reaction at the attachment site and owner satisfaction were assessed. Accuracy was determined by fulfilment of ISO 15197:2013 criteria, including Bland–Altman plotting and error grid analysis.

Results

Placing the device was easy, with 70% of cats showing no reaction. Most sensors were placed on the thoracic wall. Skin reactions at the attachment site were not present or mild in almost all cats. Owners were very satisfied with the use of the FreeStyle Libre. Median functional life of the sensor was 10 days (range 1–14). Good correlation was found between interstitial and blood glucose measurements (rho[r] = 0.88, P <0.0001). Fifty-three percent of interstitial glucose concentrations were within a maximum deviation of 15% from blood glucose concentrations and 92.7% were within the safe risk zones 0 and 1 of the surveillance error grid.

Conclusions and relevance

The flash glucose monitoring system was easy to use and owners of diabetic cats were satisfied with its use. Although the device did not completely fulfil ISO requirements, it is sufficiently accurate for glucose monitoring in diabetic cats.

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

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.

Lower Interstitial Glucose Concentrations but Higher Glucose Variability during Low-Energy Diet Compared to Regular Diet-An Observational Study in Females with Obesity

This is an observational study of interstitial glucose (IG) concentrations, IG variability and dietary intake under free-living conditions in 46 females with obesity but without diabetes. We used continuous glucose monitoring, open-ended food recording and step monitoring during regular dietary intake followed by a low-energy diet (LED). Thirty-nine participants completed both study periods. The mean BMI at baseline was 43.6 ± 6.2 kg/m2. Three weeks of LED resulted in a mean weight loss of 5.2% with a significant reduction in diurnal IG concentration but with greater glycemic variability observed during LED. The mean 24 h IG concentration decreased from 5.8 ± 0.5 mmol/L during the regular diet period to 5.4 ± 0.5 mmol/L (p < 0.001) during LED, while the mean amplitude of glycemic excursion increased from 1.5 ± 0.7 to 1.7 ± 0.7 mmol/L (p = 0.031). The positive incremental area under the curve at breakfast was significantly larger for LED compared to regular diet. The daily fiber intake and the glycemic index of breakfast meals were significantly associated with the glycemic variability during regular dietary intake. In conclusion, the 24 h mean IG concentration was lower but with more pronounced glycemic variability during LED compared to a regular diet.

Effect of Transcutaneous Radial Artery Photobiomodulation on Continuous Measures of Interstitial Glucose in a Single Subject: A Brief Report

Background: Intravenous blood irradiation with light is purported to reduce blood sugar levels in people with diabetes mellitus (DM). Transcutaneous light emitting devices are marketed for use in modulating glucose levels, yet evidence of effectiveness is scarce. Materials and methods: In a single subject (nondiabetic woman with significant family history of DM), transcutaneous photobiomodulation (PBM) at various wavelengths was applied to the radial artery immediately after a standardized meal, or at the peak glucose after the standardized meal. Data were compared with a "no intervention" control period. Interstitial glucose was measured every 5 min until return to baseline. Results: A single transcutaneous application of PBM at wavelength and dose combinations tested and when applied immediately after a test meal or at peak glucose postprandially did not affect interstitial glucose levels in a woman without DM. Conclusions: Future studies could include testing additional subjects, using repeated PBM applications and monitoring using blood glucose.

Evaluation of a flash glucose monitoring system in nondiabetic dogs with rapidly changing blood glucose concentrations

Background

A flash glucose monitoring system (FGMS; FreeStyle Libre) is useful for monitoring hypoglycemic dogs with diabetes.

Objective

To assess the utility of this FGMS in dogs with induced hypoglycemia and rapid fluctuations in blood glucose (BG) concentrations.

Animals

Twenty‐four apparently healthy research (n = 10) and teaching (n = 14) dogs.

Methods

Prospective, observational study performed in tandem with a teaching laboratory. Regular insulin was administered to dogs and resulting hypoglycemia was corrected. Before insulin administration and every 10 minutes over a 90‐minute period, serial measurements of interstitial glucose (IG) with FGMS and BG with a portable blood glucose meter (PBGM) and clinical chemistry analyzer concentrations were made. Portable blood glucose meter and FGMS readings were compared to that of the clinical chemistry analyzer. Analytical and clinical accuracy were assessed using ISO 15197:2013 criteria, including Parkes error grid analysis.

Results

The proportions of readings in the low BG range (BG <100 mg/dL) for which the test method measurement was within ±15 mg/dL of the reference BG for the PBGM and FGMS were 81.7% (161/197) and 39.1% (72/184), respectively. The proportions of readings for the PBGM and FGMS, which were not likely to affect clinical outcome according to Parkes error grid analysis, were 97.9% (233/238) and 80.1% (177/221), respectively.

Conclusions and Clinical Importance

In this model, there was limited agreement between the FGMS and reference standard BG measurements. The FGMS (measuring IG concentrations) was compared to peripheral BG concentrations, not brain‐tissue glucose concentrations, and failed to reliably detect hypoglycemia.

Validation of a flash glucose monitoring system in outpatient diabetic cats

BACKGROUND

Interstitial glucose (IG) concentration measurement using a flash glucose monitoring system (FGMS) is a noninvasive, affordable, and informative method to regulate patients with diabetes mellitus (DM) but has not been fully validated in outpatient cats with DM.

OBJECTIVES

To further validate the FreeStyle Libre FGMS in outpatient diabetic cats.

ANIMALS

Eight client-owned cats with DM.

METHODS

Prospective observational validation study. Tissue glue was used to attach the sensor to the cat. Lin's concordance correlation coefficient (ρc ) was used to compare IG concentrations measured by the FGMS to blood glucose concentrations measured using an automated biochemistry analyzer (ABA) and point-of-care glucometer (POCG).

RESULTS

Data from 15 sensor placements in 8 cats were analyzed. Paired IG and ABA glucose concentrations (139 samples) had excellent correlation (ρc  = 0.96) as did IG and POCG glucose concentrations (142 samples, ρc  = 0.92). Sensor failure or displacement were recorded for 12/15 (80%) sensor placements. Median time of sensor activity was 7 days (range, 2-13 days).

CONCLUSIONS AND CLINICAL IMPORTANCE

In outpatient cats with DM, the FGMS-measured IG concentration correlated well with ABA-measured blood glucose concentration, but a high rate of sensor failures was observed.

Assessment of postprandial hyperglycemia and circadian fluctuation of glucose concentrations in diabetic dogs using a flash glucose monitoring system

BACKGROUND

Postprandial hyperglycemia (PPH) and circadian glucose concentration fluctuations recorded in the home environment of dogs with naturally occurring diabetes mellitus (DM) have not been reported.

OBJECTIVES

To determine if a flash glucose monitoring system (FGMS; FreeStyle Libre) can detect PPH and circadian fluctuations in glucose concentrations in dogs with variably controlled DM.

ANIMALS

Fourteen client-owned dogs with DM.

METHODS

Prospective observational study. Interstitial glucose (IG) concentrations measured by the FGMS during a 13-day study period were analyzed.

RESULTS

A total of 17, 446 FGMS IG concentrations were analyzed. For all dogs analyzed together, median IG concentration measured within 30 (288 mg/dL), 60 (286 mg/dL), 90 (285 mg/dL), and 120 (285 mg/dL) minutes of meals was each significantly higher than the median IG concentration at all other times (260 mg/dL, 259 mg/dL, 258 mg/dL, and 257 mg/dL, respectively; range, 40-500 mg/dL; P < .001 for each). Median night-time IG concentration measured from all dogs on 3,547 samples recorded between 1:00 am and 6:00 am (268 mg/dL; range, 40-500 mg/dL) was significantly higher than median IG measured on 13, 899 samples at all other time points (259 mg/dL; range, 40-500 mg/dL; P < .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

The FGMS can be used for future studies of PPH and circadian fluctuations of glucose concentrations in dogs with DM in their home environment.

Comparison between a flash glucose monitoring system and a portable blood glucose meter for monitoring dogs with diabetes mellitus

Background

Flash glucose monitoring system (FGMS; FreeStyle Libre) was recently validated for use in diabetic dogs (DD). It is not known if this system is clinically useful in monitoring DD.

Objective

To compare the clinical utility of FGMS against blood glucose curves (BGCs) obtained with a portable blood glucose meter (PBGM) in monitoring DD.

Animals

Twenty dogs with diabetes mellitus.

Methods

Prospective study. Dogs with diabetes mellitus on insulin treatment for at least 1 month were included. Comparisons of insulin dose recommendations based on the in‐hospital GCs acquired using FGMS and a PBGM, consecutive‐day interstitial GCs (IGCs) acquired at home using the FGMS, and consecutive‐day, home vs hospital IGCs acquired using the FGMS were made using concordance analysis.

Results

There was good concordance between insulin dose recommendations based on FGMS and PBGM generated GCs and IGCs obtained in the 2 different environments on 2 consecutive days, but almost absent concordance between IGCs obtained on 2 consecutive days at home. Glucose nadirs were detected in 34/43 (79%) of Ambulatory Glucose Profile (AGP) reports of the FGMS. In comparison, concordant glucose nadirs were identified in 14/34 (41%) BGCs using PBGM. The individual FGMS scans and PBGM identified 60% and 9% of low IG/hypoglycemic episodes, respectively.

Conclusions and Clinical Importance

Insulin dose adjustments based on BGCs can be suboptimal. The FGMS allows a more accurate identification of the glucose nadirs and hypoglycemic episodes compared to the use of a PBGM and assessment of day‐to‐day variations in glycemic control.

Flash Glucose Monitoring Can Accurately Reflect Postprandial Glucose Changes in Healthy Adults in Nutrition Studies

OBJECTIVE

This study investigated the accuracy of a flash glucose monitoring system (FGMS) in a postprandial setting.

METHODS

Ten fasted adults without diabetes wore the FGMS sensors then consumed a standard breakfast. Their glucose levels were subsequently recorded for 2 hours, both by the FGMS and by measuring capillary glucose levels using the glucose oxidase method. The accuracy of the FGMS data was assessed using the accuracy limits stated in ISO 15197:2013.

RESULTS

FGMS measurements were mostly lower than glucose oxidase measurements (mean absolute relative difference ± SD: 25.4 ± 17.0%, p < 0.001). However, the maximum difference from baseline captured by the two methods was not significantly different (mean ± SD, glucose oxidase: 58.5 ± 18.9 mg/dl; FGMS, 54.4 ± 28.9 mg/dl, p = 0.366).

CONCLUSIONS

FGMS could track the incremental glycaemic excursions after meals in adults without diabetes, yet further studies with greater sample sizes are needed to confirm this finding.

Clinical Approach to Flash Glucose Monitoring: An Expert Recommendation

The flash glucose monitoring (FGM) system FreeStyle Libre® is a device that measures interstitial glucose in a very simple way and indicates direction and speed of glucose change. This allows persons with diabetes to prevent hypoglycemic and hyperglycemic events. Scientific evidence indicates that the system can improve glycemic control and quality of life. To obtain the maximum benefit, it is necessary to properly handle glucose values and trends. Due to the generalization of the system use, the purpose of the document is to provide recommendations for the optimal use of the device, not only in the management of glucose values and trends but also in the prevention of hypoglycemia, actuation in exercise, special situations, and retrospective analysis of the glucose data, among others.

Accuracy of a flash glucose monitoring system in dogs with diabetic ketoacidosis

Background

A factory‐calibrated flash glucose monitoring system (FGMS; FreeStyle Libre) recently was evaluated in dogs with uncomplicated diabetes mellitus. It is not known if this system is reliable during diabetic ketoacidosis (DKA).

Objectives

To assess the performance of the FGMS in dogs with DKA and to determine the effect of severity of ketosis and acidosis, lactate concentration, body condition score (BCS), and time wearing the sensor on the accuracy of the device.

Animals

Fourteen client‐owned dogs with DKA.

Methods

The interstitial glucose (IG) measurements were compared with blood glucose (BG) measurements obtained using a validated portable glucometer. The influence of changes in metabolic variables (β‐hydroxybutyrate, pH, bicarbonate, and lactate) and the effect of BCS and time wearing on sensor performance were evaluated. Accuracy was determined by fulfillment of ISO15197:2013 criteria.

Results

Metabolic variables, BCS, and time wearing were not associated with the accuracy of the sensor. Good agreement between IG measurements and BG was obtained both before and after DKA resolution (r = .88 and r = .93, respectively). Analytical accuracy was not achieved, whereas clinical accuracy was demonstrated with 100% and 99.6% of results in zones A + B of the Parkes consensus error grid analysis before and after DKA resolution, respectively.

Conclusions and Clinical Importance

Changes in metabolic variables, BCS, and time wearing do not seem to affect agreement between IG and BG. Despite not fulfilling the ISO requirements, the FGMS provides clinically accurate estimates of BG in dogs with DKA.

Flash Glucose Monitoring: Differences Between Intermittently Scanned and Continuously Stored Data

The flash glucose monitoring system FreeStyle Libre (Abbott Diabetes Care Ltd., Witney, UK) measures interstitial glucose concentrations and continuously stores measurement values every 15 minutes. To obtain a current glucose reading, users have to scan the sensor with the reader. In a clinical trial, 5% of the scanned data showed relative differences of more than ±10% compared with continuously stored data points (median -0.5%). Such differences might impact results of studies using this system. It should be indicated whether scanned or continuously stored data were used for analyses. Health care professionals might have to differentiate between data reports from clinical software and the scanned data their patients are provided with. Additional information on these differences and their potential impact on therapeutic decisions would be helpful.

Brain Activation in Response to Personalized Behavioral and Physiological Feedback From Self-Monitoring Technology: Pilot Study

Background

The recent surge in commercially available wearable technology has allowed real-time self-monitoring of behavior (eg, physical activity) and physiology (eg, glucose levels). However, there is limited neuroimaging work (ie, functional magnetic resonance imaging [fMRI]) to identify how people’s brains respond to receiving this personalized health feedback and how this impacts subsequent behavior.

Objective

Identify regions of the brain activated and examine associations between activation and behavior.

Methods

This was a pilot study to assess physical activity, sedentary time, and glucose levels over 14 days in 33 adults (aged 30 to 60 years). Extracted accelerometry, inclinometry, and interstitial glucose data informed the construction of personalized feedback messages (eg, average number of steps per day). These messages were subsequently presented visually to participants during fMRI. Participant physical activity levels and sedentary time were assessed again for 8 days following exposure to this personalized feedback.

Results

Independent tests identified significant activations within the prefrontal cortex in response to glucose feedback compared with behavioral feedback (P<.001). Reductions in mean sedentary time (589.0 vs 560.0 minutes per day, P=.014) were observed. Activation in the subgyral area had a moderate correlation with minutes of moderate-to-vigorous physical activity (r=0.392, P=.043).

Conclusion

Presenting personalized glucose feedback resulted in significantly more brain activation when compared with behavior. Participants reduced time spent sedentary at follow-up. Research on deploying behavioral and physiological feedback warrants further investigation.

A comparison of adipose tissue interstitial glucose and venous blood glucose during postprandial resistance exercise in patients with type 2 diabetes

Resistance exercise during the postprandial period lowers venous glucose concentrations in individuals with type 2 diabetes, but the impact of resistance exercise on interstitial glucose concentrations is not well understood. The objective of this study was to compare subcutaneous adipose tissue interstitial glucose and venous blood glucose concentrations during postprandial resistance exercise in patients with type 2 diabetes. Eleven individuals completed two trials in a random order including a no-exercise (NoEx) and a postprandial resistance exercise trial (M-Ex). During the trials, the individuals consumed a meal and either remained sedentary (NoEx) or performed a session of resistance training beginning 45 min after the meal (M-Ex) while interstitial and venous glucose concentrations were simultaneously measured. Venous glucose during exercise was ~11% lower ( P = 0.05) during M-Ex (8.0 ± 0.5 mmol/l) compared with NoEx (9.0 ± 0.5 mmol/l) whereas interstitial glucose during M-Ex (10.4 ± 0.7 mmol/l) was not different compared with interstitial glucose during NoEx (10.1 ± 0.7 mmol/l). Bland-Altman plots revealed that the difference (bias) between interstitial and venous glucose during exercise was more than twofold greater during M-Ex (2.36 ± 2.07 mmol/l) compared with NoEx (1.11 ± 1.69 mmol/l). The mean (33.8 ± 6.2 mmol/l) and median (34.7 ± 6.3 mmol/l) absolute relative difference during exercise were 73% and 78% greater compared with the mean (19.5 ± 4.1 mmol/l) and median (19.5 ± 4.1 mmol/l) absolute relative difference during NoEx ( P = 0.04). Resistance exercise has unequal effects on glucose concentrations within different bodily compartments as exercise reduced venous glucose concentrations but not adipose tissue interstitial glucose concentrations in the abdominal region in individuals with type 2 diabetes. NEW & NOTEWORTHY This is the first study to compare subcutaneous adipose tissue interstitial glucose concentrations and venous blood glucose concentrations during postprandial resistance exercise in individuals with type 2 diabetes. We find that resistance exercise effectively reduces systemic venous blood glucose concentrations but not subcutaneous adipose tissue interstitial glucose concentrations in the abdominal region. Resistance exercise has differential effects on glucose concentrations depending on its compartmentalization within the body.

Discrepancies Between Blood Glucose and Interstitial Glucose-Technological Artifacts or Physiology: Implications for Selection of the Appropriate Therapeutic Target

BACKGROUND

For decades, the major source of information used to make therapeutic decisions by patients with diabetes has been glucose measurements using capillary blood samples. Knowledge gained from clinical studies, for example, on the impact of metabolic control on diabetes-related complications, is based on such measurements. Different to traditional blood glucose measurement systems, systems for continuous glucose monitoring (CGM) measure glucose in interstitial fluid (ISF). The assumption is that glucose levels in blood and ISF are practically the same and that the information provided can be used interchangeably. Thus, therapeutic decisions, that is, the selection of insulin doses, are based on CGM system results interpreted as though they were blood glucose values.

METHODS

We performed a more detailed analysis and interpretation of glucose profiles obtained with CGM in situations with high glucose dynamics to evaluate this potentially misleading assumption.

RESULTS

Considering physical activity, hypoglycemic episodes, and meal-related differences between glucose levels in blood and ISF uncover clinically relevant differences that can make it risky from a therapeutic point of view to use blood glucose for therapeutic decisions.

CONCLUSIONS

Further systematic and structured evaluation as to whether the use of ISF glucose is more safe and efficient when it comes to acute therapeutic decisions is necessary. These data might also have a higher prognostic relevance when it comes to long-term metabolic consequences of diabetes. In the long run, it may be reasonable to abandon blood glucose measurements as the basis for diabetes management and switch to using ISF glucose as the appropriate therapeutic target.

Professional continuous glucose monitoring in clinical practice 2010

Professional continuous glucose monitoring (PCGM) is a 3-5 day test done to evaluate diabetes control. The PCGM test uses interstitial glucose measurements done every 5 min with a glucose-oxidase-impregnated membrane. The PCGM test evaluates glucose control retrospectively with the glucose results being unknown to the patient until the results are downloaded after the testing period. The PCGM test allows the practitioner and patient to evaluate the effect of diet, physical activity, medications, and lifestyle events on glucose control during the 24 h period. Developing a PCGM program at a medical office involves understanding reimbursement issues and having trained staff and a process in place to initiate the test and download and interpret the data.

Optimum subcutaneous glucose sampling and fourier analysis of continuous glucose monitors

BACKGROUND

The objective of this article was to focus on the application of harmonic decomposition to continuous glucose monitor (CGM) measurements. We show evidence of an attenuation of fast variations of interstitial glucose when compared to blood in type 1 diabetes mellitus (T1DM) and, using information theory, propose optimal sampling schedules associated with the use and study of CGMs.

METHOD

Using a cohort of 26 T1DM subjects, wearing two Navigator sensors for 1 to 3 days, we analyzed the frequency content of each glucose signal and derived across subject frequency cutoffs using discrete Fourier transform and common signal processing techniques.

RESULTS

We observed a significant difference in the frequency content of blood glucose compared to interstitial glucose in T1DM, providing evidence toward the existence of a diffusion process between blood and interstitial glucose, acting as a low-pass filter. Furthermore, we obtained a 15-minutes sampling schedule for optimal comparison of CGM values to blood reference.

CONCLUSION

Blood glucose and interstitial glucose have different dynamics, as shown by harmonic analysis, and these differences have consequences on advisable schedules for accuracy studies of CGMS.