The impact of continuous glucose monitoring for people with type 1 diabetes: A focus on everyday life

In type 1 diabetes (T1D) the individual's immune system attacks the insulin producing beta cells of the pancreas and destroys them. Therefore, people with T1D need exogenous insulin to survive, however, achieving optimal glycaemic control while avoiding hypoglycaemia remains a challenge despite rapid advancements in insulin administration technology and better insulin preparations. To inject the right dose of insulin, it is essential that the amount of glucose in the blood is known. Checking blood glucose levels several times a day and administering the correct amount of insulin based by taking into account several other factors (e.g., carbohydrate load to be consumed, planned physical activity) is a daily reality for people with T1D, but also a 'task' with a major impact on quality of life (QOL). For many decades, the frequent execution of capillary finger-stick tests was the only way to have a notion of blood glucose values. Unfortunately, not many people perform this test frequent enough, while successful intensive insulin treatment requires close self-monitoring of blood glucose. By using capillary finger-stick tests, many glucose fluctuations were missed during the day, and the nights remained unknown. The introduction of continuous glucose monitoring (CGM) has overcome some of the limitations of capillary finger-stick tests. There are generally two types of CGM systems available depending on the level of user-interaction needed to receive sensor glucose information: real-time CGM (rtCGM) continuously shows updated glucose information and provides real-time alerts and alarms for hypo- and hyperglycaemia; intermittently scanned CGM (isCGM) requires the user to deliberately scan the sensor to obtain the same information as rtCGM, and therefore does not have alarms for hypo- and hyperglycaemia. Randomised controlled trials (RCTs) with CGM showed favourable results on hypoglycaemia risk, HbA1c (only for rtCGM), but often neglected the patient perspective of diabetes self-management and omitted the incorporation of patient-reported outcome measures. Additionally, RCT circumstances do not reflect the real-life use of the devices, because the study population is often highly motivated to do well, and therefore, these results are not always generalisable to the broad population of people living with T1D and thereby hamper with reimbursement policies. Real-world evidence (RWE) can provide filling for the knowledge gap and combine clinical with patient reported outcomes. Uniquely, Belgium has launched reimbursement programmes for both rtCGM and isCGM, providing an excellent soil for large real-life usage studies. Therefore, in the first two parts of this project, we evaluated the use of rtCGM and isCGM and their effect on glycaemic control, QOL, and acute diabetes-related complications in real-world clinical practice. First, rtCGM was introduced in a population where people were selected, not on the basis of stringent inclusion and exclusion criteria imposed by a healthcare organiser, but rather based on the clinical expertise of experienced diabetes teams. This approach proved successful as the diabetes teams selected highly motivated people who were able to attain a high benefit from rtCGM technology during at least two years with positive effects on patient-reported outcomes, especially people with impaired awareness of hypoglycaemia. Second, isCGM was introduced in an unselected population as part of the nationwide full reimbursement of isCGM for all people with T1D in Belgium without restrictions or specified inclusion criteria. Adults and children were very satisfied with the use of isCGM with additional benefits on acute diabetes-related complications and school absence for children. In well-controlled adults and youth, HbA1c rose after introduction of this new technology. It became clear that the use of this technology requires a certain level of user interaction and diabetes knowledge to prove beneficial. Therefore, a good understanding on the glucose sensor output is needed and regular re-education is warranted to avoid people making wrong treatment decisions based on CGM data. In the third part of this project, we searched for evidence-based alternative sensor insertion sites for people who use isCGM, but cannot harness its full potential due to issues with a too visible sensor attached to the back of the upper arm. In an interventional study, we identified the upper thigh as a good alternative, accuracy-wise, for the arm. The abdomen, the main insertion site for rtCGM devices, proved to be unreliable in this factory-calibrated sensor. As a general conclusion, with our studies, we have shown that the Belgian way of working, namely introducing technology within conventions with a focus on diabetes education, can have beneficial effects on health and patient-reported outcomes. This has made isCGM and rtCGM available to a wider group of people with T1D.status: publishe

Glycaemic control on nutritional support: finding stability in unstable times

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Accuracy and Precision of Flash Glucose Monitoring Sensors Inserted Into the Abdomen and Upper Thigh Compared to the Upper Arm (out of sight)

Nowadays, most Belgian patients with type 1 diabetes use flash glucose monitoring (FreeStyle® Libre™ [FSL]) to check their glucose values, but some patients find the sensor on the upper arm too visible. The aim of this study was to compare accuracy and precision of FSL sensors when placed on different sites. Twenty-three adults with type 1 diabetes used three FSL sensors simultaneously for 14 days on upper arm, abdomen, and upper thigh. FSL measurements were compared to capillary blood glucose (BG) measurements obtained with built-in FSL BG meter. Aggregated mean absolute relative difference was 11.8±12.0%, 18.5±18.4% and 12.3±13.8% for arm, abdomen (p=0.002 vs. arm) and thigh (p=0.5 vs. arm) respectively. Clarke error grid analysis for arm and thigh were comparable (zone A: 84.9% vs. 84.5%, p=0.6), while less accuracy was seen for abdomen (69.4%, p=0.01). Apart from the first day, accuracy of FSL sensors on arm and thigh was more stable across the 14-day wear duration than accuracy of sensors on abdomen, which deteriorated mainly during week two (p<0.0005). Aggregated precision absolute relative difference was markedly lower for arm/thigh (10.9±11.9%) compared to arm/abdomen (20.9±22.8%) (p=0.002). Our results indicate that accuracy and precision of FSL sensors placed on upper thigh are comparable to upper arm, whereas abdomen performed unacceptably poor.status: publishe

Intermittently scanned continuous glucose monitoring is associated with high satisfaction but increasedHbA1cand weight in well-controlled youth with type 1 diabetes

OBJECTIVE: We undertook a 24-month prospective observational single-center real-world trial to study impact of access to intermittently scanned continuous glucose monitoring (isCGM) on quality of life (QOL) and glycemic control of youth with type 1 diabetes (T1D). METHODS: Between September 2016 and November 2017, 138 children and adolescents with T1D were recruited. Demographic, metabolic, and QOL data were collected during 24 months of routine follow-up. Primary endpoint was the evolution of QOL, with secondary outcomes change in HbA1c, occurrence of acute diabetes complications, and school absenteeism. RESULTS: Ninety-two percent of participants found isCGM more user-friendly than capillary finger-stick tests and had high treatment satisfaction, without change in diabetes-specific QOL. HbA1c significantly increased from 7.2% (7.0-7.3) (55 mmol/mol [53-56]) at baseline to 7.6% (7.4-7.8) (60 mmol/mol [57-62]) at 12 months (P < .0001) and was unchanged up to 24 months. Overall increase was mainly driven by children with baseline HbA1c <7.0% (<53 mmol/mol). Additionally, BMI adjusted for age was higher at study end. In year before isCGM, 228 days per 100 patient-years of school absenteeism were reported, which dramatically decreased to 13 days per 100 patient-years (P = .016) after 24 months. Parents of children also reported less work absenteeism (P = .011). CONCLUSION: The use of isCGM by T1D pediatrics is associated with high treatment satisfaction and fewer days of school absence. However, increased HbA1c and weight may reflect a looser lifestyle, with less attention to diet and more avoidance of hypoglycemia. Intensive education specifically focusing on these points may mitigate these issues.status: publishe

Quality of Life and Glucose Control After 1 Year of Nationwide Reimbursement of Intermittently Scanned Continuous Glucose Monitoring in Adults Living With Type 1 Diabetes (FUTURE): A Prospective Observational Real-World Cohort Study

OBJECTIVE: In 2016, nationwide reimbursement of intermittently scanned continuous glucose monitoring (isCGM) for people living with type 1 diabetes treated in specialist diabetes centers was introduced in Belgium. We undertook a 12-month prospective observational multicenter real-world study to investigate impact of isCGM on quality of life and glycemic control. RESEARCH DESIGN AND METHODS: Between July 2016 and July 2018, 1,913 adults with type 1 diabetes were consecutively recruited in three specialist diabetes centers. Demographic, metabolic, and quality of life data were collected at baseline, 6 months, and 12 months of standardized clinical follow-up. The primary end point was evolution of quality of life from baseline to 12 months. Secondary outcome measures were, among others, change in HbA1c, time spent in different glycemic ranges, occurrence of acute diabetes complications, and work absenteeism. RESULTS: General and diabetes-specific quality of life was high at baseline and remained stable, whereas treatment satisfaction improved (P < 0.0001). Admissions for severe hypoglycemia and/or ketoacidosis were rare in the year before study (n = 63 out of 1,913; 3.3%), but decreased further to 2.2% (n = 37 out of 1,711; P = 0.031). During the study, fewer people reported severe hypoglycemic events (n = 280 out of 1,913 [14.6%] vs. n = 134 out of 1,711 [7.8%]; P < 0.0001) or hypoglycemic comas (n = 52 out of 1,913 [2.7%] vs. n = 18 out of 1,711 [1.1%]; P = 0.001) while maintaining HbA1c levels. Fewer people were absent from work (n = 111 out of 1,913 [5.8%] vs. n = 49 out of 1,711 [2.9%]; P < 0.0001). Time spent in hypoglycemia significantly decreased in parallel with less time in range and more time in hyperglycemia. Eleven percent (n = 210) of participants experienced skin reactions, leading to stopping of isCGM in 22 participants (1%). CONCLUSIONS: Nationwide unrestricted reimbursement of isCGM in people with type 1 diabetes treated in specialist diabetes centers results in higher treatment satisfaction, less severe hypoglycemia, and less work absenteeism, while maintaining quality of life and HbA1c.status: publishe

Effect of Continuous Glucose Monitoring on Glycemic Control, Acute Admissions and Quality of Life: A Real-World Study

Randomized controlled trials evaluating real-time continuous glucose monitoring (RT-CGM) patients with type 1 diabetes (T1D) show improved glycemic control, but limited data are available on real-world use.status: publishe