Validation of the Continuous Glucose Monitoring System (CGMS) by the use of two CGMS simultaneously in pregnant women with type 1 diabetes mellitus

Postprandial interval walking-effect on blood glucose in pregnant women with gestational diabetes

BACKGROUND

During pregnancy, postprandial hyperglycemia may increase the risk of complications such as fetal macrosomia. However, evidence on beneficial effects of physical activity on postprandial hyperglycemia is sparse.

OBJECTIVE

This study aimed to investigate the effect of 20 minutes of postprandial interval walking on glycemic control and glycemic variability in pregnant women diagnosed as having gestational diabetes mellitus.

STUDY DESIGN

A crossover controlled trial including 14 pregnant women (gestational age 31.8±1.3 weeks) diagnosed as having gestational diabetes mellitus (75 g oral glucose load with 2-hour venous plasma glucose of ≥9.0 mmol/L) was conducted. Participants completed a 4-day intervention period and a 4-day control period with 3 days in between. In each study period, participants received a fixed and identical diet. In the intervention period, participants engaged in 20 minutes of postprandial interval walking after breakfast, lunch, and dinner. Interval walking comprised alternating 3 minutes of slow and fast intervals. Interstitial glucose concentrations were determined during both study periods with a continuous glucose monitor. The mixed effects model was used to compare differences between exercise and no exercise.

RESULTS

Of note, 20 minutes of postprandial interval walking significantly reduced glycemic control during daytime hours relative to the control period (4-day mean glucose, 5.31 [5.04-5.59] vs 5.53 [5.25-5.81] mmol/L [95.6 (90.7-100.6) vs 99.5 (94.5-104.6) mg/dL]; P<.05). On each individual trial day, interval walking significantly reduced glycemic control during daytime hours on day 1 (mean glucose, 5.19 [4.92-5.47] vs 5.55 [5.27-5.83] mmol/L [93.4 (88.6-98.5) vs 99.9 (94.9-104.9) mg/dL]; P=.00), day 2 (mean glucose, 5.32 [5.05-5.60] vs 5.57 [5.29-5.84] mmol/L [95.8 (90.9-100.8) vs 100.3 (95.2-105.1) mg/dL]; P=.00), and day 3 (mean glucose, 5.27 [5.00-5.54] vs 5.46 [5.19-5.74] mmol/L [94.9 (90.0-99.7) vs 98.3 (93.4-103.3) mg/dL]; P=.00), but not on day 4.

CONCLUSION

A total of 20 minutes of postprandial interval walking seems to be an effective way to control postprandial glucose excursions in women with gestational diabetes mellitus.

Cycling reduces blood glucose excursions after an oral glucose tolerance test in pregnant women: a randomized crossover trial

The aim of this study was to evaluate the effect of an acute bout of cycling immediately after oral glucose intake on glucose metabolism in pregnant women at risk for gestational diabetes mellitus (GDM). Fifteen pregnant women with BMI ≥ 27 kg/m² were enrolled in a randomized crossover controlled study and underwent two oral glucose tolerance tests (OGTTs) ingesting 75 g of glucose followed by either 20 min of stationary cycling at moderate intensity (65%-75% maximal heart rate) or rest. Using continuous glucose monitors, glucose was measured up to 48 h after the OGTT. Glucose, insulin, and C-peptide were determined at baseline and after 1 and 2 h. One hour after glucose intake, mean blood glucose was significantly lower after cycling compared with rest (p = 0.002). Similarly, mean glucose peak level was significantly lower after cycling compared with after rest (p = 0.039). Lower levels of insulin and C-peptide were observed after 1 h (p < 0.01). Differences in glucose measurements after 2 h and up to 48 h were not statistically different. We found that 20 min of cycling at moderate intensity after glucose intake reduced blood glucose excursions in pregnant women at risk for GDM. ClinicalTrials.gov Identifier: NCT03644238. Novelty Bullets In pregnant women, we found that cycling after glucose intake resulted in significantly lower glucose levels compared with rest. The exercise intervention studied is feasible for pregnant women and could be readily used to reduce glucose excursions.

Effect of High Versus Low Carbohydrate Intake in the Morning on Glycemic Variability and Glycemic Control Measured by Continuous Blood Glucose Monitoring in Women with Gestational Diabetes Mellitus-A Randomized Crossover Study

Carbohydrate is the macronutrient that has the greatest impact on blood glucose response. Limited data are available on how carbohydrate distribution throughout the day affects blood glucose in women with gestational diabetes mellitus (GDM). We aimed to assess how a high-carbohydrate morning-intake (HCM) versus a low-carbohydrate-morning-intake (LCM), affect glycemic variability and glucose control. In this randomized crossover study continuous glucose monitoring (CGM) was performed in 12 women with diet treated GDM (75 g, 2-h OGTT ≥ 8.5 mmol/L), who went through 2 × 3 days of HCM and LCM. A within-subject-analysis showed a significantly higher mean amplitude of glucose excursions (MAGE) (0.7 mmol/L, p = 0.004) and coefficient of variation (CV) (5.1%, p = 0.01) when comparing HCM with LCM, whereas a significantly lower mean glucose (MG) (-0.3 mmol/L, p = 0.002) and fasting blood glucose (FBG) were found (-0.4 mmol/L, p = 0.01) on the HCM diet compared to the LCM diet. In addition, insulin resistance, expressed as Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), decreased significantly during HCM. Results indicate that a carbohydrate distribution of 50% in the morning favors lower blood glucose and improvement in insulin sensitivity in women with GDM, but in contrary gives a higher glycemic variability.

Postprandial walking reduces glucose levels in women with gestational diabetes mellitus

The purpose of this study was to investigate blood glucose changes, as measured by a continuous glucose monitoring system, that occur in women with gestational diabetes mellitus (GDM) following an acute bout of moderate-intensity walking after consuming a high-carbohydrate/low-fat meal. This study found that moderate-intensity walking induced greater postprandial glucose control compared with sedentary activity and it appears that moderate-intensity activity may be used to reduce postprandial glucose levels in women with GDM.

Accuracy of Continuous Glucose Monitoring Measurements in Normo-Glycemic Individuals

Background

The validity of continuous glucose monitoring (CGM) is well established in diabetic patients. CGM is also increasingly used for research purposes in normo-glycemic individuals, but the CGM validity in such individuals is unknown. We studied the accuracy of CGM measurements in normo-glycemic individuals by comparing CGM-derived versus venous blood-derived glucose levels and measures of glycemia and glycemic variability.

Methods

In 34 healthy participants (mean age 65.7 years), glucose was simultaneously measured every 10 minutes, via both an Enlite^® CGM sensor, and in venous blood sampled over a 24-hour period. Validity of CGM-derived individual glucose measurements, calculated measures of glycemia over daytime (09:00h-23:00h) and nighttime (23:00h-09:00h), and calculated measures of glycemic variability (e.g. 24h standard deviation [SD]) were assessed by Pearson correlation coefficients, mean absolute relative difference (MARD) and paired t-tests.

Results

The median correlation coefficient between CGM and venous glucose measurements per participant was 0.68 (interquartile range: 0.40–0.78), and the MARD was 17.6% (SD = 17%). Compared with venous sampling, the calculated measure of glycemia during daytime was 0.22 mmol/L higher when derived from CGM, but no difference was observed during nighttime. Most measures of glycemic variability were lower with CGM than with venous blood sampling (e.g., 24h SD: 1.07 with CGM and 1.26 with venous blood; p-value = 0.004).

Conclusion

In normo-glycemic individuals, CGM-derived glucose measurements had good agreement with venous glucose levels. However, the measure of glycemia was higher during the day and most measures of glycemic variability were lower when derived from CGM.

The efficacy and effectiveness of continuous glucose monitoring during pregnancy: a systematic review

OBJECTIVE

Diabetic pregnancies carry a high risk for both mother and child, especially when glycemic control is poor. A novel technique that aims to improve glycemic control is the continuous glucose monitor (CGM). This tool is already in use to improve pregnancy outcome. This review presents the available evidence on the efficacy of CGM use in pregnancy and the effectiveness on pregnancy outcome.

METHODS

A systematic search was conducted using PubMed, EMBASE, and the Cochrane Libraries for articles on CGM in pregnancy. We evaluated the selected articles with particular attention for clinical and cost-effectiveness of CGM to improve pregnancy outcome.

RESULTS

We retrieved 5032 articles, 11 of which remained as relevant after selection according to predefined criteria. Most studies were limited to the evaluation of the role of CGM on clinical decision making. Only 2 studies were randomized controlled trials (RCTs) evaluating the effect on pregnancy outcome. One small RCT on retrospective CGM showed a significant reduction in third-trimester HbA1c and a significant reduction in neonatal macrosomia. A second RCT on real-time CGM did not show any effect on either glycemic control or on pregnancy outcome.

CONCLUSIONS

Current evidence on the efficacy of CGM on improving glycemic control during pregnancy as well as on the effectiveness on pregnancy outcome is limited to 2 RCTs with contradicting results. Evidence on the cost-effectiveness is lacking. Further proper RCTs on the effectiveness and cost-effectiveness of CGM in pregnancy are required before wide implementation in practice.

Continuous glucose monitoring in pregnancy: new frontiers in clinical applications and research

Current treatment of diabetes in pregnancy relies on intermittent self-monitoring of blood glucoses using finger sticks to monitor capillary blood glucoses. Continuous glucose monitoring (CGM) systems are an emerging technology that allow frequent glucose measurements (every 5 min) and the ability to monitor glucose trends in real time. Although these devices are currently expensive and mildly invasive to use, there is huge potential for their use in both the research and clinical realms. From a research perspective, there is the potential to better understand glucose metabolism in pregnancy, both in patients with and without diabetes. For the treating clinician, CGM has the potential to improve detection of hyperglycemic excursions as well as asymptomatic hypoglycemia and the data to improve management of glucose levels in diabetes patients. In this article, we review current literature examining use of CGM in both research and clinical applications.

Patient satisfaction and barriers to initiating real-time continuous glucose monitoring in early pregnancy in women with diabetes

AIM

To evaluate self-reported satisfaction and barriers to initiating real-time continuous glucose monitoring in early pregnancy among women with pregestational diabetes.

METHODS

Fifty-four women with Type 1 diabetes and 14 women with Type 2 diabetes were offered continuous glucose monitoring for 6 days at median 9 (range 6-14) gestational weeks and were asked to answer a semi-structured questionnaire on patient satisfaction.

RESULTS

Median HbA1c was 49 (range 34-86) mmol/mol) [6.6 (5.3-10.0) %] and duration of diabetes was 12 (0.5-37) years. Continuous glucose monitoring was used for 6 (0.5-7) days, with 43 (65%) women using continuous glucose monitoring for at least 5 days. The women experienced 2.7 (0-12) alarms per 24 h, of which approximately one third was technical alarms and one third disturbed their sleep. Sixteen women (24%) reported discomfort with continuous glucose monitoring during daytime and twelve (18%) during sleep. Many women reported improved diabetes understanding (52%) and would recommend continuous glucose monitoring to others (83%). Twenty-four patients (36%) had continuous glucose monitoring removed earlier than planned ( before the intended 6 days of initial monitoring). Ten women (15%) did not wish to use continuous glucose monitoring again in pregnancy. Main causes behind early removal of continuous glucose monitoring were self-reported skin irritation, technical problems and continuous glucose monitoring inaccuracy. No differences were found in continuous glucose monitoring use, inconvenience or compliance with respect to diabetes type.

CONCLUSIONS

The majority of pregnant women with diabetes found real-time continuous glucose monitoring useful and the intervention was equally tolerated regardless of diabetes type. Nevertheless, continuous glucose monitoring was frequently removed earlier than planned, primarily because of skin irritation, technical problems and inaccuracy.

Statistical approach of assessing the reliability of glucose sensors: the GLYCENSIT procedure

BACKGROUND

In healthcare, patients with diabetes are instructed on how to apply intensified insulin therapy in an optimal manner. Tight blood glucose control is also performed on patients treated in the intensive care unit (ICU). Different blood glucose meters and glucose monitoring systems (GMSs) are used to achieve this goal, and some may lack reliability.

METHODS

The GLYCENSIT procedure is a statistical assessment tool we are proposing for evaluating the significant difference of paired glucose measurements. The performance of the GlucoDay system in the ICU is analyzed with GLYCENSIT.

RESULTS

THE GLYCENSIT ANALYSIS COMPRISES THREE PHASES: testing possible persistent measurement behavior as a function of the glycemic range, testing the number of measurement errors with respect to a standard criterion for binary assessment of glucose sensors, and computing the tolerance intervals that indicate possible test sensor deviations for new observations. The probability of the tolerance intervals directly reflects the number of samples and additionally improves current assessment techniques. The method can be tuned according to the clinician's preferences regarding significance level, tolerance level, and glycemic range cutoff values. The measurement behavior of the GlucoDay sensor is found to be persistent but inaccurate and returns wide tolerance intervals, suggesting that the GlucoDay sensor may not be sufficiently reliable for glycemia control in the ICU.

CONCLUSIONS

The GLYCENSIT procedure aims to serve as statistical guide for clinicians in the assessment of glucose sensor devices.

The role of continuous glucose monitoring in clinical decision-making in diabetes in pregnancy

BACKGROUND

The continuous glucose monitoring system (CGMS) is a novel tool to assess 24-h glucose fluctuations. In pregnancies complicated by diabetes, where excellent glucose control is desired to improve maternal and fetal outcomes, CGMS may have a role in fine-tuning management.

AIMS

To assess the usefulness of CGMS in pregnant women with diabetes for medical decision-making and to evaluate patient tolerability and perception of usefulness.

METHODS

Pregnant women with diabetes at the Werribee Mercy Hospital were offered CGMS in the setting of their standard diabetes care. Treating clinicians were asked if the CGMS altered management decisions from those based on conventional glucose monitoring. The accuracy of the CGMS was assessed by comparison with the patients' finger-prick glucose readings. Patients completed a feedback questionnaire after having the CGMS and viewing their results.

RESULTS

CGMS traces (n = 68) were obtained in 55 pregnant women - 37 with gestational diabetes, ten with type 2 and eight with type 1 diabetes. Forty-two of 68 (62%) traces were assessed as providing additional information which altered clinical management decisions. This included showing undetected postprandial hyperglycaemia and overnight hypoglycaemia. Subject feedback was generally positive, with 37 of 48 (77%) respondents reporting that the benefits of the CGMS outweighed the inconvenience.

CONCLUSION

CGMS is a well-tolerated clinically useful tool in the management of gestational diabetes and pre-existing diabetes in pregnancy.