Continuous glucose monitoring and diabetes health outcomes: a critical appraisal

Backpropagation Neural Network-Based Machine Learning Model for Prediction of Blood Urea and Glucose in CKD Patients

Diabetes mellitus and its complication such as heart disease, stroke, kidney failure, etc. is a serious concern all over the world. Hence, monitoring some important blood parameters non-invasively is of utmost importance, that too with high accuracy. This paper presents an in-house developed system, which will be helpful for diabetes patients with Chronic Kidney Disease (CKD) to monitor blood urea and glucose. This manuscript discusses a comparative study for the prediction of blood urea and glucose using Backpropagation Artificial Neural Network (BP- ANN) and Partial Least Square Regression (PLSR) model. The NVIDIA Jetson Nano board controls the five fixed LED wavelengths in the Near Infrared (NIR) region from [Formula: see text] to [Formula: see text] with a constant emission power of 1.2 mW. The spectra for 57 laboratory prepared samples conforming with major blood constituents of the blood sample were recorded. From these samples, 53 spectra were used for training/calibration of the BP-ANN/PLSR model and the remaining 4 samples were used for validating the model. The PLSR model predicts blood urea and glucose with a Root Mean Square Error (RMSE) of 0.88 & 12.01 mg/dL, Coefficient of Determination R2 = 0.93 & R2 = 0.97, Accuracy of 94.2 % and 90.14 %, respectively. To improve the prediction accuracy, BP-ANN model is applied. Later the Principal Component Analysis (PCA) technique was applied to these 57 spectra values. These PCA values were used to train and validate the BP-ANN model. After applying the BP-ANN model, the prediction of blood urea & glucose improved remarkably, which achieved RMSE of 0.69 mg/dL, R2 = 0.96, Accuracy of 95.96 % for urea and RMSE of 2.06 mg/dL, R2 = 0.99, and Accuracy of 98.65 % for glucose. The system performance is then evaluated with Bland Altman analysis and Clarke Error Grid Analysis (CEGA).

A Noninvasive Accurate Measurement of Blood Glucose Levels with Raman Spectroscopy of Blood in Microvessels

Raman spectra of human skin obtained by laser excitation have been used to non-invasively detect blood glucose. In previous reports, however, Raman spectra thus obtained were mainly derived from the epidermis and interstitial fluid as a result of the shallow penetration depth of lasers in skin. The physiological process by which glucose in microvessels penetrates into the interstitial fluid introduces a time delay, which inevitably introduces errors in transcutaneous measurements of blood glucose. We focused the laser directly on the microvessels in the superficial layer of the human nailfold, and acquired Raman spectra with multiple characteristic peaks of blood, which indicated that the spectra obtained predominantly originated from blood. Incorporating a multivariate approach combining principal component analysis (PCA) and back propagation artificial neural network (BP-ANN), we performed noninvasive blood glucose measurements on 12 randomly selected volunteers, respectively. The mean prediction performance of the 12 volunteers was obtained as an RMSEP of 0.45 mmol/L and R² of 0.95. It was no time lag between the predicted blood glucose and the actual blood glucose in the oral glucose tolerance test (OGTT). We also applied the procedure to data from all 12 volunteers regarded as one set, and the total predicted performance was obtained with an RMSEP of 0.27 mmol/L and an R² of 0.98, which is better than that of the individual model for each volunteer. This suggested that anatomical differences between volunteer fingernails do not reduce the prediction accuracy and 100% of the predicted glucose concentrations fall within Region A and B of the Clarke error grid, allowing acceptable predictions in a clinically relevant range. The Raman spectroscopy detection of blood glucose from microvessels is of great significance of non-invasive blood glucose detection of Raman spectroscopy. This innovative method may also facilitate non-invasive detection of other blood components.

Effect of Linagliptin Versus Metformin on Glycemic Variability in Patients with Impaired Glucose Tolerance

BACKGROUND

Impaired glucose tolerance (IGT) and glycemic variability may be associated with increased risk of micro- and macrovascular complications. The aim of this study was to assess the effect of linagliptin versus metformin on glycemic variability in patients with IGT.

MATERIAL AND METHODS

A randomized, double-blind clinical trial with parallel groups was carried out in 16 adult patients with IGT, overweight or obesity. All patients signed an informed consent. The therapies were randomly assigned: (a) metformin 500 mg bid (n = 8) or (b) linagliptin 5 mg a.m. and placebo p.m. (n = 8), both for 90 days. At the beginning of the trial and 3 months later, fasting glucose, glycated hemoglobin A1c, oral glucose tolerance test (OGTT), and glycemic variability [area under the curve (AUC) of glucose, mean amplitude of glycemic excursion (MAGE), standard deviation (SD) of glucose, coefficient of variation (CV) of glucose, and mean blood glucose (MBG)] were measured. Mann-Whitney U, Wilcoxon, and Fisher exact tests were used for statistical analyses.

RESULTS

Both groups were similar in basal characteristics. After linagliptin administration, a significant decrease in glucose levels at 120 min of OGTT (9.0 ± 0.9 vs. 6.9 ± 2.2 mmol/L, P = 0.012) was observed. Glycemic variability showed a similar behavior and there were no significant differences in the AUC, MAGE, SD of glucose, CV of glucose, and MBG between groups.

CONCLUSION

Linagliptin administration resulted in better glycemic control according to the decrease of glucose levels by the OGTT at 120 min in patients with IGT. Meanwhile, glycemic variability was not modified in any of the study groups.

Continuous Glucose Monitoring Systems: A Review

There have been continuous advances in the field of glucose monitoring during the last four decades, which have led to the development of highly evolved blood glucose meters, non-invasive glucose monitoring (NGM) devices and continuous glucose monitoring systems (CGMS). Glucose monitoring is an integral part of diabetes management, and the maintenance of physiological blood glucose concentration is the only way for a diabetic to avoid life-threatening diabetic complications. CGMS have led to tremendous improvements in diabetic management, as shown by the significant lowering of glycated hemoglobin (HbA1c) in adults with type I diabetes. Most of the CGMS have been minimally-invasive, although the more recent ones are based on NGM techniques. This manuscript reviews the advances in CGMS for diabetes management along with the future prospects and the challenges involved.

Glycosylated hemoglobin and albumin-corrected fructosamine are good indicators for glycemic control in peritoneal dialysis patients

PURPOSE

Diabetes mellitus (DM) is the most common cause of end-stage renal disease and is an important risk factor for morbidity and mortality after dialysis. However, glycemic control among such patients is difficult to assess. The present study examined glycemic control parameters and observed glucose variation after refilling different kinds of fresh dialysate in peritoneal dialysis (PD) patients.

METHODS

A total of 25 DM PD patients were recruited, and continuous glucose monitoring system (CGMS) was applied to measure interstitial fluid (ISF) glucose levels at 5-min intervals for 3 days. Patients filled out diet and PD fluid exchange diaries. The records measured with CGMS were analyzed and correlated with other glycemic control parameters such as fructosamine, albumin-corrected fructosamine (AlbF), glycosylated hemoglobin (HbA1c), and glycated albumin levels.

RESULTS

There were significant correlations between mean ISF glucose and fructosamine (r = 0.45, P<0.05), AlbF (r = 0.54, P<0.01), and HbA1c (r = 0.51, P<0.01). The ISF glucose levels in glucose-containing dialysate increased from approximately 7-8 mg/dL within 1 hour of exchange in contrast to icodextrin dialysate which kept ISF glucose levels unchanged.

CONCLUSION

HbA1c and AlbF significantly correlated with the mean ISF glucose levels, indicating that they are reliable indices of glycemic control in DM PD patients. Icodextrin dialysate seems to have a favorable glycemic control effect when compared to the other glucose-containing dialysates.

The impact of hypoglycaemia on quality of life and related patient-reported outcomes in Type 2 diabetes: a narrative review

As a common side effect of insulin treatment for diabetes, hypoglycaemia is a constant threat and can have far-reaching and potentially devastating consequences, including immediate physical injury as well as more pervasive cognitive, behavioural and emotional effects. Moreover, as a significant limiting factor in achieving optimal glycaemic control, exposure to hypoglycaemia can influence diabetes self-management. Although hypoglycaemia is known to occur in Type 2 diabetes, its morbidity and impact on the individual are not well recognized. The aim of the current review is to examine published evidence to achieve a synthesis of the scope and significance of the potential detriment caused by hypoglycaemia to individuals with Type 2 diabetes. The implications of these observations for treatment and research have also been considered. A narrative review was performed of empirical papers published in English since 1966, reporting the effect of hypoglycaemia on quality of life and related outcomes (including generic and diabetes-specific quality of life, emotional well-being and health utilities) in Type 2 diabetes. Research demonstrates the potential impact of hypoglycaemia on the lives of people with Type 2 diabetes, from an association with depressive symptoms and heightened anxiety, to impairment of the ability to drive, work and function in ways that are important for quality of life. Few studies consider hypoglycaemia as an explanatory variable in combination with quality of life or related primary endpoints. As a consequence, there is a pressing need for high-quality research into the overall impact of hypoglycaemia on the lives of people with Type 2 diabetes.

Non-inferiority of insulin glargine versus insulin detemir on blood glucose variability in type 1 diabetes patients: a multicenter, randomized, crossover study

BACKGROUND

This study compared the effects of insulin glargine and insulin detemir on blood glucose variability under clinical practice conditions in patients with type 1 diabetes (T1D) using glulisine as the mealtime insulin.

METHODS

This was a multicenter, crossover trial in 88 randomized T1D patients: 54 men and 34 women, 46.8±13.7 years old, with a duration of diabetes of 18±9 years and hemoglobin A1c level of 7.1±0.7%. The per-protocol population included 78 patients: 44 received glargine/detemir and 34 detemir/glargine in the first/second 16-week period, respectively. The primary end point was the coefficient of variation (CV) of fasting blood glucose (FBG). Secondary end points included variability of pre-dinner blood glucose, mean amplitude of glycemic excursions, mean of daily differences, and doses and number of daily insulin injections. The non-inferiority criterion was an insulin glargine/insulin detemir FBG CV ratio with a 95% confidence interval (CI) upper limit ≤1.25.

RESULTS

The non-inferiority criterion was satisfied with a mean value of 1.016 (95% CI=0.970-1.065). Intention-to-treat analysis confirmed the non-inferiority with a 95% CI upper limit=1.062. No significant differences were found on secondary objectives, but there was a trend to higher doses and number of daily injections with insulin detemir. A total of eight (four glargine and four detemir) patients reported nine serious adverse events (including one severe episode of hypoglycemia). None of them was considered as related to basal insulins. Serious adverse events led to treatment discontinuation in two patients of the detemir group and none in the glargine group.

CONCLUSIONS

In T1D patients under clinical practice conditions, insulin glargine was non-inferior to insulin detemir regarding blood glucose variability, as assessed by CV of FBG.

Effect of short-term use of a continuous glucose monitoring system with a real-time glucose display and a low glucose alarm on incidence and duration of hypoglycemia in a home setting in type 1 diabetes mellitus

BACKGROUND

The objective of this study was to examine whether setting the low glucose alarm of a Guardian® REAL-Time continuous glucose monitoring system (CGMS) to 80 mg/dl for 3 days and providing instructions to users reduce the risk of hypoglycemia under free-living conditions in individuals with type 1 diabetes mellitus (T1DM).

METHODS

Fourteen participants with T1DM aged 26.1±6.0 years (mean±standard deviation) were fitted with a CGMS and assigned for 3 days to either an alarm [low and high blood glucose (BG) alarms set at 80 and 200 mg/dl, respectively] or no alarm condition, with each treatment administered to all participants following a counterbalanced design. All participants were given detailed instructions on how to respond appropriately to low glucose alarms.

RESULTS

The CGMS with alarm reduced the incidence of hypoglycemia (CGMS readings≤65 mg/dl) by 44% as well as the time spent below this hypoglycemic threshold by 64% without increasing average BG levels. However, the CGMS with alarm had no effect on the incidence of symptomatic hypoglycemia.

CONCLUSIONS

Short-term use of the CGMS with alarm, together with appropriate instructions for users, reduces the incidence and duration of hypoglycemia, but only to a limited extent, in part because it overestimates BG in the low glucose range.

Use of sensors in the treatment and follow-up of patients with diabetes mellitus

Glucose control is the cornerstone of Diabetes Mellitus (DM) treatment. Although self-regulation using capillary glycemia (SRCG) still remains the best procedure in clinical practice, continuous glucose monitoring systems (CGM) offer the possibility of continuous and dynamic assessment of interstitial glucose concentration. CGM systems have the potential to improve glycemic control while decreasing the incidence of hypoglycemia but the efficiency, compared with SRCG, is still debated. CGM systems have the greatest potential value in patients with hypoglycemic unawareness and in controlling daily fluctuations in blood glucose. The implementation of continuous monitoring in the standard clinical setting has not yet been established but a new generation of open and close loop subcutaneous insulin infusion devices are emerging making insulin treatment and glycemic control more reliable.

Pascal's wager: combining continuous glucose monitoring and continuous subcutaneous insulin infusion

Pascal's Wager is a suggestion posed by the French Philosopher, Blaise Pascal, that even though the existence of God cannot be determined through reason, a person should wager that God exists because he or she has everything to gain and nothing to lose. In the area of consideration here, the optimum experimental trial of the combined use of continuous subcutaneous insulin infusion and real-time continuous glucose monitoring in free-living individuals with type 1 diabetes providing rock-solid evidence of clinical benefit has not been performed. Nevertheless, there is considerable enthusiasm for combining the technologies among healthcare professionals, patients, and manufacturers based on the belief that this approach to diabetes care must be beneficial beyond the available evidence (i.e., reason).

Determining clinical and psychological benefits and barriers with continuous glucose monitoring therapy

BACKGROUND

Preventing the complications of diabetes requires tight control and minimizing blood glucose fluctuation. Pursuing these goals increases the risk of severe hypoglycemia. The authors hoped to identify if using continuous glucose monitoring (CGM) decreased the incidence of severe hypoglycemia, resulted in less fear of hypoglycemia, and improved patient empowerment and what impact CCM had on quality of life (QOL) issues.

METHODS

Questionnaires were used to gather demographic data, to measure educational experiences with CGM, QOL issues concerning fear of hypoglycemia and severe hypoglycemia, confidence to make changes to insulin regimens before and after using CGM, and the incidence of severe hypoglycemia before and while using CGM, and to assess the impact of CGM on QOL.

RESULTS

The data and answers reported suggest significantly less fear of hypoglycemia and severe hypoglycemia and increased patient empowerment with CGM. Further shown is a reduced incidence of acute complications as evidenced by significantly decreased incidence of severe hypoglycemia. CGM appears to have a significant, positive impact on the stress associated with having and managing diabetes.

CONCLUSIONS

Using CGM as part of the diabetes self-management plan offers the potential to significantly improve user outcomes as measured by QOL, reduction of fear, and patient empowerment. Using CGM can allow patients to achieve tighter control of their blood glucose values with reduced fear of hypoglycemia, reduced incidence of severe hypoglycemia, and a decreased sense of burden from having diabetes.

Treatment satisfaction and quality of life for an integrated continuous glucose monitoring/insulin pump system compared to self-monitoring plus an insulin pump

BACKGROUND

Little is known about how the most advanced technology affects treatment satisfaction and health-related quality of life (HRQOL) in adults with diabetes. This study was designed to assess treatment satisfaction and HRQOL among users of an integrated real-time (RT) continuous glucose monitoring (CGM)/continuous subcutaneous insulin infusion (CSII) system compared with those using self-monitoring of blood glucose (SMBG) with CSII.

METHODS

Participants were 311 adult respondents to an Internet survey, 162 using RT-CGM/CSII, 149 using SMBG + CSII (median age 43 years; type 1 diabetes 94%; diabetes duration >15 years 61%; median insulin use 15 years). Respondents completed instruments assessing glucose monitoring system and insulin delivery system convenience, interference, burden, glucose control efficacy, cost satisfaction, overall satisfaction, and treatment preference, as well as quality of life (diabetes-related worries, social burden, and psychological well-being). Real-time CGM/CSII users also assessed specific elements of the RT-CGM/CSII system. Group differences were assessed using analysis of covariance controlling for respondent characteristics.

RESULTS

The RT-CGM/CSII group gave significantly better ratings than the SMBG + CSII group for their glucose monitoring system's glucose control efficacy, overall satisfaction, desire to switch, and willingness to recommend, and significantly worse ratings for interference with daily activities. The RT-CGM/CSII group gave significantly better ratings than the SMBG + CSII group for their insulin delivery system's convenience and glucose control efficacy, overall satisfaction, desire to switch, and willingness to recommend. Real-time CGM/CSII users gave positive ratings of all system features.

CONCLUSIONS

Users of the integrated RT-CGM/CSII system reported more benefits of treatment, higher treatment satisfaction and quality of life, and greater preference for this system than SMBG + CSII users.

Clinical need for continuous glucose monitoring in the hospital

Automation and standardization of the glucose measurement process have the potential to greatly improve glycemic control, clinical outcome, and safety while reducing cost. The resources required to monitor glycemia in hospitalized patients have thus far limited the implementation of intensive glucose management to patients in critical care units. Numerous available and up-and-coming technologies are targeted for the hospital patient population. Advantages and limitations of these devices are discussed herewith in.

An overview and commentary on retrospective, continuous glucose monitoring for the optimisation of care for people with diabetes

INTRODUCTION

Normoglycaemia in people with diabetes results in improved outcome. Continuous glucose monitoring provides detailed diagnostic information used to optimise therapy with the goal of achieving normoglycaemia. The objective of this study was to review the published literature evaluating the single device available for blinded, professional clinical use of continuous glucose monitoring; in particular all randomised controlled trials (RCTs) and relevant observational studies.

METHODS

Published studies (to 31 March 2009) using the Medtronic MiniMed Continuous Glucose Monitoring System (CGMS System Gold, Medtronic MiniMed, Inc., Northridge, CA) were identified using appropriate search terms in a series of clinical databases including: Medline, Pubmed, Google Scholar and Scientific Web of Knowledge. Other measures were also taken such as reviewing the reference lists.

FINDINGS

In addition to an extensive range of non-randomised studies using the device, seven randomised controlled trials were identified, of which five were in children. Although HbA1c was explicitly stated as the primary endpoint in four studies, the studies were only adequately powered to detect large, between-group minimum differences (range 0.5 to 1.0% HbA1c). Only two studies included subjects with type 2 diabetes. Other endpoints included the frequency of hypoglycaemia and hyperglycaemia. Within-group HbA1c decreases were observed in all but one study. The crude, weighted mean improvement in HbA1c across the studies using the device was 0.6% (range 0% to 0.8%). When compared to a control measure the weighted, mean marginal benefit in HbA1c was 0.2%. No studies recorded how the information was utilised to modify treatment, such as changes in dose titration or treatment regimen.

CONCLUSIONS

Devices such as the professional CGMS provide detailed diagnostic information. However, any consequent changes in care and outcome can only result from the appropriate application of this information. Although there was a notable improvement in glucose control (HbA1c), existing studies were largely underpowered and did not capture the resulting treatment changes that could lead to improved outcome.

Reducing glycaemic variability in type 1 diabetes self-management with a continuous glucose monitoring system based on wired enzyme technology

AIMS/HYPOTHESIS

This study was designed to investigate the use and impact of a continuous glucose monitoring system (the FreeStyle Navigator) under home-use conditions in the self-management of type 1 diabetes.

METHODS

A 20 day masked phase, when real-time data and alarms were not available, was compared with a subsequent 40 day unmasked phase for a number of specified measures of glycaemic variability. HbA(1c) (measured by DCA 2000) and a hypoglycaemia fear survey were recorded at the start and end of the study.

RESULTS

The study included 48 patients with type 1 diabetes (mean age 35.7 +/- 10.9, range 18-61 years; diabetes duration 17.0 +/- 9.5 years). Two patients did not complete the study for personal reasons. Comparing masked (all 20 days) and unmasked (last 20 days) phases, the following reductions were seen: time outside euglycaemia from 11.0 to 9.5 h/day (p = 0.002); glucose SD from 3.5 to 3.2 mmol/l (p < 0.001); hyperglycaemic time (>10.0 mmol/l) from 10.3 to 8.9 h/day (p = 0.0035); mean amplitude of glycaemic excursions (peak to nadir) down by 10% (p < 0.001); high blood glucose index down by 18% (p = 0.0014); and glycaemic risk assessment diabetes equation score down by 12% (p = 0.0013). Hypoglycaemic time (<3.9 mmol/l) decreased from 0.70 to 0.64 h/day without statistical significance (p > 0.05). Mean HbA(1c) fell from 7.6 +/- 1.1% at baseline to 7.1 +/- 1.1% (p < 0.001). In the hypoglycaemia fear survey, the patients tended to take less snacks at night-time after wearing the sensor.

CONCLUSIONS/INTERPRETATION

Home use of a continuous glucose monitoring system has a positive effect on the self-management of diabetes. Thus, continuous glucose monitoring may be a useful tool to decrease glycaemic variability.

Improved glycemic control through continuous glucose sensor-augmented insulin pump therapy: prospective results from a community and academic practice patient registry

BACKGROUND

Conducted by highly experienced investigators with abundant time and resources, phase III studies of continuous glucose sensing (CGS) may lack generalizability to everyday clinical practice.

METHOD

Community or academic practices in six Central and Eastern European or Mediterranean countries prospectively established an anonymized registry of consecutive patients with type 1 insulin-dependent diabetes mellitus starting CGS-augmented insulin pump therapy with the Paradigm X22 (Medtronic MiniMed, Northridge, CA) under everyday conditions, without prior CGS with another device. We compared glycosylated hemoglobin (GHb) values before and after 3 months of CGS and assessed relationships between insulin therapy variables and glycemia-related variables at weeks 1, 4, and 12 of CGS.

RESULTS

Of 102 enrolled patients, 85 (83%) with complete weeks 1, 4, and 12 sensor data and baseline/3-month GHb data were evaluable. Evaluable patients were approximately 54% male and approximately 75% adult (mean age, 33.2 +/- 16.9 years) with longstanding diabetes and high personal/family education levels. Mean GHb declined significantly after 3 months of CGS (7.55 +/- 1.33% at baseline to 6.81 +/- 1.08% after 12 weeks, 0.74% absolute decrease, P < 0.001). The absolute GHb reduction correlated significantly (P < 0.0005) with baseline GHb: larger absolute reductions tended to occur when baseline levels were higher. An increased basal insulin dose as a percentage of the total daily insulin dose and a decreased daily bolus count from week 1 to week 12 of CGS predicted GHb improvement from baseline to week 12.

CONCLUSIONS

CGS-augmented insulin pump therapy appears to improve glycemic control in type 1 diabetes in varied everyday practice settings.

Multicentre, randomised, controlled study of the impact of continuous sub-cutaneous glucose monitoring (GlucoDay) on glycaemic control in type 1 and type 2 diabetes patients

AIM

This randomised study was designed to investigate the impact of continuous glucose monitoring (CGM) for 48h on glycaemic control with a 3-month follow-up in patients with type 1 (T1D) or type 2 (T2D) diabetes.

METHODS

A total of 48 patients with poor glycaemic control (HbA(1c): 8-10.5%) underwent CGM for 48h using the GlucoDay((R)) system (A. Menarini Diagnostics), after which they were randomly assigned to treatment adjustments based on either their CGM profile (CGM group) or their usual self-monitoring of blood glucose (SMBG group). HbA(1c) measurement and 48-h CGM were repeated 3 months later.

RESULTS

Altogether, 34 patients with either T1D (n=9) or T2D (n=25) completed the study; seven patients chose to leave the study, and seven patients in the CGM group were excluded because their baseline CGM graphs were not interpretable. HbA(1c) levels decreased significantly in the CGM group (n=14, -0.63+/-0.27%; P=0.023), but not in the controls (n=20, -0.28+/-0.21%; P=0.30). In T2D patients, the improvement associated with CGM vs SMBG was due to HbA(1c) decreases (mean: -0.63+/-0.34%; P=0.05 vs -0.31+/-0.29%; P=0.18, respectively). However, HbA(1c) did not change significantly with CGM in T1D patients. Comparisons of CGM data at baseline and after 3 months showed no significant changes in glucose control, glucose variability or hypoglycaemia. No major adverse events related to the GlucoDay system were reported.

CONCLUSION

This is the first randomised study showing that CGM improves glycaemic control in patients with T2D.

Continuous glucose monitoring health outcomes

Continuous glucose monitoring (CGM) is a new tool that has recently become available to people with diabetes. Properly designing and conducting trials in order to answer important questions regarding the clinical usefulness of CGM is very difficult and fraught with many confounding variables and unique challenges. Initial clinical trials using older technology using retrospective data analysis have not shown unequivocal benefit; however, more recent data using real-time CGM suggest significant improvements in important clinical outcomes such as hemoglobin A1c, time spent in the hypo- and hyperglycemic range, glucose variability, quality of life, and perceived value to physicians and patients. Additional variables such as age of the subject and duration of sensor use have important implications in defining the benefits of CGM in a heterogeneous population with diabetes. This review will present the most relevant recent literature and comment on the methodological difficulties that have made this field challenging.

Clinical experience with continuous glucose monitoring in adults

Despite recent advances in therapy, achieving adequate glycemic control may be difficult for a large number of patients with diabetes. Real-time (RT)-continuous glucose monitoring (CGM) has the potential to improve glycemic control through immediate feedback to the properly trained patient. However, limitations exist both in interpreting the results of published randomized clinical trials on CGM use and in extrapolating the results to the diabetes population at large. This review summarizes the evidence for use, identifies suitable candidates, describes optimal implementation, and employs case scenarios in order to emphasize practical aspects of RT-CGM use in adults. Establishment of expectations and comprehensive education in intensive insulin therapy and RT-CGM use are necessary for successful implementation. Because the technology has been shown to be most useful in patients who are actively viewing and responding to RT data, patients should receive explicit instructions for active self-adjustment of insulin and lifestyle elements. While the technology is improving, false alarms remain a significant barrier to optimal use. The utility of RT-CGM for patients with severe hypoglycemia or hypoglycemia unawareness has not been established. Finally, studies are needed to determine the sustainability of improvements in glycemic control, as well as cost-effectiveness and practicality of implementation into busy real-world practice.

Randomized controlled trial to assess the impact of continuous glucose monitoring on HbA(1c) in insulin-treated diabetes (MITRE Study)

AIMS

To determine whether continuous glucose information provided through use of either the GlucoWatch G2 Biographer or the MiniMed continuous glucose monitoring system (CGMS) results in improved glycated haemoglobin (HbA(1c)) for insulin-treated adults with diabetes mellitus, relative to an attention control and standard care group.

METHODS

Four hundred and four adults taking at least two daily insulin injections and with two consecutive HbA(1c) values > or = 7.5% were recruited to this randomized controlled trial (RCT). All were trained at baseline to use the same monitor for traditional capillary glucose testing throughout the 18-month study. The CGMS group were asked to wear the device three times during the first 3 months of the trial and on another three occasions thereafter. The GlucoWatch group wore the device a minimum of four times per month and a maximum of four times per week during the first 3 months and as desired for the remainder of the trial. Trained diabetes research nurses used downloaded data to guide therapy adjustments. Proportional reduction in HbA(1c) from baseline to 18 months was the primary outcome measure.

RESULTS

Neither an intention-to-treat nor per-protocol analysis showed improvement in HbA(1c) in the device groups compared with standard care. For the intention-to-treat analysis, when the standard care group was compared with each of the other groups, this equated to differences in mean relative HbA(1c) reduction (95% confidence interval) from baseline to 18 months of 3.5% (-1.3 to 8.3; GlucoWatch), 0.7% (-4.1 to 5.5; CGMS), and -0.1% (-4.6 to 4.3; attention control).

CONCLUSIONS

The additional information provided by these devices did not result in improvements in HbA(1c) in this population.

Continuous glucose monitoring: a review of biochemical perspectives and clinical use in type 1 diabetes

Self-monitoring of blood glucose is a fundamental part of diabetes management. It is mandatory for tight glucose control. For the past 30 years, intermittent measurement of capillary blood glucose has been the method of choice for self-monitoring. The main disadvantage of such measurements is that they provide isolated glucose values which do not reflect variations occurring throughout the day and night. Hence systems monitoring blood glucose concentrations on a "continuous basis" have been developed. In clinical studies, different devices were shown to provide useful information on glycemic excursions in people with diabetes with sufficient accuracy. Thus, in clinical practice, this approach has also been shown to help in the medical management leading to a reduction in glycated hemoglobin and glycemic variability. However, because of lack of experience, this technology has yet to replace standard capillary blood glucose monitoring. In this paper, we review the biochemical perspectives of continuous glucose monitoring and its clinical use in type 1 diabetes.