The Use of Continuous Glucose Monitoring With Remote Monitoring Improves Psychosocial Measures in Parents of Children With Type 1 Diabetes: A Randomized Crossover Trial

Glucose management for exercise using continuous glucose monitoring (CGM) and intermittently scanned CGM (isCGM) systems in type 1 diabetes: position statement of the European Association for the Study of Diabetes (EASD) and of the International Society for Pediatric and Adolescent Diabetes (ISPAD) endorsed by JDRF and supported by the American Diabetes Association (ADA)

Physical exercise is an important component in the management of type 1 diabetes across the lifespan. Yet, acute exercise increases the risk of dysglycaemia, and the direction of glycaemic excursions depends, to some extent, on the intensity and duration of the type of exercise. Understandably, fear of hypoglycaemia is one of the strongest barriers to incorporating exercise into daily life. Risk of hypoglycaemia during and after exercise can be lowered when insulin-dose adjustments are made and/or additional carbohydrates are consumed. Glycaemic management during exercise has been made easier with continuous glucose monitoring (CGM) and intermittently scanned continuous glucose monitoring (isCGM) systems; however, because of the complexity of CGM and isCGM systems, both individuals with type 1 diabetes and their healthcare professionals may struggle with the interpretation of given information to maximise the technological potential for effective use around exercise (i.e. before, during and after). This position statement highlights the recent advancements in CGM and isCGM technology, with a focus on the evidence base for their efficacy to sense glucose around exercise and adaptations in the use of these emerging tools, and updates the guidance for exercise in adults, children and adolescents with type 1 diabetes. Graphical abstract.

Glucose management for exercise using continuous glucose monitoring (CGM) and intermittently scanned CGM (isCGM) systems in type 1 diabetes: position statement of the European Association for the Study of Diabetes (EASD) and of the International Society for Pediatric and Adolescent Diabetes (ISPAD) endorsed by JDRF and supported by the American Diabetes Association (ADA)

Physical exercise is an important component in the management of type 1 diabetes across the lifespan. Yet, acute exercise increases the risk of dysglycaemia, and the direction of glycaemic excursions depends, to some extent, on the intensity and duration of the type of exercise. Understandably, fear of hypoglycaemia is one of the strongest barriers to incorporating exercise into daily life. Risk of hypoglycaemia during and after exercise can be lowered when insulin-dose adjustments are made and/or additional carbohydrates are consumed. Glycaemic management during exercise has been made easier with continuous glucose monitoring (CGM) and intermittently scanned continuous glucose monitoring (isCGM) systems; however, because of the complexity of CGM and isCGM systems, both individuals with type 1 diabetes and their healthcare professionals may struggle with the interpretation of given information to maximise the technological potential for effective use around exercise (ie, before, during and after). This position statement highlights the recent advancements in CGM and isCGM technology, with a focus on the evidence base for their efficacy to sense glucose around exercise and adaptations in the use of these emerging tools, and updates the guidance for exercise in adults, children and adolescents with type 1 diabetes.

Has subsidized continuous glucose monitoring improved outcomes in pediatric diabetes?

INTRODUCTION

In 2017, the Australian Federal Government fully subsidized continuous glucose monitoring (CGM) devices for patients under 21 years of age with T1D with the aim of reducing rates of severe hypoglycaemia (SH) and improving metabolic control. The aim of this study was to reports on metabolic outcomes in youth from a single tertiary centre.

METHODS

The study design was observational. Data were obtained on youth who commenced CGM between May 2017 and December 2019.

RESULTS

Three hundred and forty one youth who commenced CGM and had clinical outcome data for a minimum of 4 months. 301, 261, 216, 172, and 125 had outcome data out to 8, 12, 16, 20, and 24 months, respectively. Cessation occurred between 27.9% and 32.8% of patients 12 to 24 months after CGM commencement. HbA1c did not change in patients who continued to use CGM. In the 12 months prior to starting CGM the rate of severe hypoglycaemia events were 5.0 per 100 patient years. The rates of severe hypoglycaemia in those continuing to use CGM at 4, 8, 12, 16, 20, and 24 months, were 5.2, 5.1, 1.6, 6.1, 2.4, and 0 per 100 patient years, respectively.

DISCUSSION

Our experience of patients either ceasing or underusing CGM is less than reported in other cohorts but is nonetheless still high. There may have been a reduction in rates of severe hypoglycaemia over the 24 months follow up period; however, the absolute numbers of events were so low as to preclude meaningful statistical analysis.

Sources and Valence of Information Impacting Parents' Decisions to Use Diabetes Technologies in Young Children <8 Years Old with Type 1 Diabetes

There are multiple information sources available to assist families in learning about rapidly advancing diabetes technologies as care options for their children. This study explored where and from whom families of young children with type 1 diabetes get information about diabetes technologies and the valence (positive vs. negative) of that information. Semi-structured interviews were conducted with parents (86% mothers) of 79 youth <8 years old with type 1 diabetes for ≥6 months, ([mean ± standard deviation] age 5.2 ± 1.5 years, diabetes duration 2.4 ± 1.3 years, 77% white, A1c 63 ± 10 mmol/mol [7.9 ± 0.9%], 66% pump-treated, 58% using continuous glucose monitors [CGMs]). Interviews were transcribed and underwent content analysis to derive central themes. Most parents reported learning about new technologies from three direct sources: diabetes care providers, people with diabetes, and caregivers of children with diabetes. Parents also cited three indirect sources of information: online forums, publications, and diabetes-specific conferences. Parents reported hearing primarily positive things about technologies. Families not using pump and/or CGM noted reluctance to use technology due to family-specific concerns (e.g., cost, child's unwillingness to wear device) rather than information from outside sources. In this subset of parents, many still expressed willingness to initiate use once family-specific concerns were resolved. Parents of young children received largely positive information about diabetes technologies, primarily from health care providers and others familiar with using devices personally or for their children. To maximize diabetes technology use in young children, it is incumbent upon providers to ensure families receive balanced realistic information about benefits and barriers.

Exploring Parental Experiences of Using a Do-It-Yourself Solution for Continuous Glucose Monitoring Among Children and Adolescents With Type 1 Diabetes: A Qualitative Study

BACKGROUND

MiaoMiao (MM) is a Bluetooth transmitter, which when paired with a smart phone/device, converts the Abbott FreeStyle Libre flash glucose monitoring system into a Do-It-Yourself (DIY) continuous glucose monitor (CGM). Families are increasingly adopting DIY CGM solutions, but little is known about parent and child experiences with these add-on technologies. We aimed to explore experiences of families using MM-CGM including challenges faced and their advice to others who may choose to use the technology.

METHODS

Between May and July 2019, we conducted 12 semistructured interviews (in person or via video conference) with parents of children (aged ≤16 years) with type 1 diabetes using MM-CGM. Interviews were audio recorded; professionally transcribed and key themes were identified through thematic analysis.

RESULTS

Overall, parents used MM-CGM to proactively manage their child's blood glucose. In all participants, this led to a perceived decrease in frequency of hypoglycemia. Participants reported that the visibility and easy access to blood glucose readings, glucose trends, and customized alarms on parent's phones decreased their disease burden and improved their sleep quality. Common barriers to using MM-CGM included difficulty of the setting up process, connectivity issues, and lack of support from medical teams.

CONCLUSION

This study highlights the potential feasibility of using a DIY CGM system like MM-CGM, which could be an empowering and cost-effective tool for enabling remote monitoring of blood glucose in real time.

When Low Blood Sugars Cause High Anxiety: Fear of Hypoglycemia Among Parents of Youth With Type 1 Diabetes Mellitus

OBJECTIVES

Hypoglycemia is the most common acute complication of type 1 diabetes (T1D), and the potential short- and long-term sequelae can cause children and parents to develop significant fear of hypoglycemia (FOH). FOH and associated anxiety can be disruptive to activities of daily living and lead to reduced quality of life. We sought to determine the extent of FOH among parents of children with T1D within our clinic and to identify factors associated with greater FOH.

METHODS

Two hundred sixty-four parents of youth (2 to 18 years of age; mean ± standard deviation, 12.4±3.5 years) with T1D completed a survey that included demographic and disease-specific questions, the Spielberger State-Trait Anxiety Inventory and the Hypoglycemia Fear Survey---Parent version (HFS-P).

RESULTS

Of the 264 participants, 207 completed the full HFS-P, with a mean score of 67±19 (range, 31 to 119). The most frequent worries related to the child being hypoglycemic while alone or asleep. Higher HFS-P scores were also associated with more frequent and severe hypoglycemic episodes, higher state-trait anxiety scores, use of a continuous glucose monitor and more frequent blood glucose checks. Higher HFS-P scores were also associated with worse parental sleep quality and less parental engagement with treatment plans.

CONCLUSIONS

Parents of children with T1D experience FOH, especially during times of high vulnerability. Moreover, FOH could potentially impact clinical care (with parents being reluctant to administer suggested insulin doses) and quality of life (due to parental/child sleep disruption). Further studies are needed to develop and evaluate interventions aimed at reducing FOH in parents of youth with T1D.

Young Children with Type 1 Diabetes: Sleep, Health-Related Quality of Life, and Continuous Glucose Monitor Use

While children with type 1 diabetes (T1D) and their parents report significant sleep problems, few studies have focused on young children and included health-related quality of life (HRQOL) as an outcome of sleep disturbance. In addition, relatively little is known about the use of diabetes devices, such as continuous glucose monitors (CGMs), in young children and their link with sleep disturbances. This brief report examines the relationship between sleep quality and HRQOL and explores sleep disturbances related to CGM use in a sample of young children with T1D. Data are from the baseline of a behavioral intervention pilot for 46 parents of children ages 2-5 years with T1D. Parents reported on their child's sleep disturbances as a result of nighttime blood glucose monitoring (NBGM). Sleep was measured objectively in a subset of children (N = 11) who wore accelerometers for a 5-day period. All parents completed measures of pediatric and parental HRQOL. Greater child sleep disturbance due to NBGM was associated with lower pediatric HRQOL. Child sleep disturbances were negatively associated with parental life satisfaction. In addition, children who used CGM experienced fewer sleep disturbances than those who did not. However, parents of children who used CGM experienced greater sleep disturbances related to a higher frequency of NBGM. Pediatric and parental HRQOL were most related to child sleep disturbances by NBGM. CGM use may be associated with better child sleep, as parents are less likely to wake their child for NBGM, although CGM use may also be associated with greater sleep difficulties in parents. Future studies should further explore the relationship between sleep and technology use and impact on clinical outcomes in young children with T1D and their parents.

Strukturierte Diabetesschulung

Successful diabetes treatment requires a high degree of therapy-related competence and everyday coping from the patients. The necessary knowledge and skills are developed in diabetes education programs together with the diabetes health care team. This article presents history, structural components and methodological-didactic aspects, gives an up-to-date overview of existing programs in Germany and an outlook on future diabetes education in view of technological progress.

Modern diabetes devices in the school setting: Perspectives from school nurses

OBJECTIVE

To explore the experiences, practices, and attitudes of school nurses related to modern diabetes devices (insulin pumps, continuous glucose monitors, and hybrid-closed loop systems).

RESEARCH DESIGN AND METHODS

Semistructured interviews were conducted with 40 public school nurses caring for children in elementary and middle schools. Developed with stakeholder input, the interview questions explored experiences working with devices and communicating with the health care system. Deidentified transcripts were analyzed through an iterative process of coding to identify major themes.

RESULTS

School nurses reported a range of educational backgrounds (58% undergraduate, 42% graduate), geographic settings (20% urban, 55% suburban, 25% rural), and years of experience (20% <5 years, 38%, 5-15 years, 42% >15 years). Four major themes emerged: (a) As devices become more common, school nurses must quickly develop new knowledge and skills yet have inconsistent training opportunities; (b) Enthusiasm for devices is tempered by concerns about implementation due to poor planning prior to the school year and potential disruptions by remote monitors; (c) Barriers exist to integrating devices into schools, including school/classroom policies, liability/privacy concerns, and variable staff engagement; and (d) Collaboration between school nurses and providers is limited; better communication may benefit children with diabetes.

CONCLUSIONS

Devices are increasingly used by school-aged children. School nurses appreciate device potential but share structural and individual-level challenges. Guiding policy is needed as the technology progressively becomes standard of care. Enhanced training and collaboration with diabetes providers may help to optimize school-based management for children in the modern era.

The Role of Parent Self-Regulation in Youth Type 1 Diabetes Management

PURPOSE OF REVIEW

Youth with strong self-regulation (SR), or the ability to manage thoughts, emotions, and behaviors, engage in more effective type 1 diabetes (T1D) management. However, while parent support and engagement are critical to ensuring positive youth T1D outcomes, it is rarely considered that parents' SR may also influence youth T1D management. If this is the case, novel interventions to improve parents' SR or ensure adequate support for parents with SR challenges offer great potential to improve family functioning and youth T1D management.

RECENT FINDINGS

Theoretical and preliminary empirical evidence suggests that parental SR impacts family processes that support youth T1D treatment regimen adherence. Furthermore, parent and youth SR likely interact, with high parent SR enhancing the positive effects of high youth SR or compensating for low youth SR. Continued research is needed to better understand the ways in which parent SR matters to youth T1D management and identify how to support improvements in T1D management among families of parents with low SR.

Parental Experiences of Continuous Glucose Monitoring in Danish Children with Type 1 Diabetes Mellitus

PURPOSE

To explore parents 'experience of having a child aged 4-9 years with type 1 diabetes mellitus (T1DM) using continuous glucose monitor (CGM).

DESIGN AND METHODS

The study was a qualitative study. Twelve families were recruited for individual or dyadic interviews through purposeful and convenience sampling procedures.

RESULTS

Thematic analysis generated three main themes: 1) Living in the context of the unpredictability of diabetes 2) Establishing a sense of control and security with the CGM 3) Learning to use and trust the CGM and educating other caregivers.

CONCLUSIONS

Living in the context of the unpredictability of T1DM causes a loss of stability and control as T1DM pervades family life and transforms everyday routines. CGM use seems to increase opportunities for other family activities, as it provides parents with a sense of control and moderates the pervasiveness of T1DM. Yet the parents have to learn how to trust and use the CGM and take on the burdensome task of training and trusting other caregivers.

PRACTICE IMPLICATIONS

The CGM is used as an integral part of T1DM care in everyday life. Therefore, it should be accessible to families. Health-care professionals should be aware of how to assist parents with how to use and trust the CGM. Furthermore, parents may need help and support in educating other caregivers on how to use the CGM. This could be done through teaching sessions, written materials and recorded demonstrations of CGM use.

Impact on the well-being perceived by caregivers of children and adolescents with type 1 diabetes following the use of interstitial glucose measurement systems

INTRODUCTION

Type 1 diabetes mellitus (DM-1) is one of the most common chronic childhood diseases, and it is essential to optimize glycemic control in order to avoid complications. For years, interstitial glucose measurement systems (MGI systems) have been among the new technologies at the forefront of self-care.

OBJECTIVES

To determine the impact on the well-being of the caregivers of patients with type 1 diabetes mellitus under 18 years of age, controlled at a Pediatric Diabetes Unit of a third level hospital, of the use of MGI systems.

MATERIAL AND METHODS

This was an observational, descriptive and analytical cohort study based on a questionnaire completed by the patients' caregivers, as well as from the patient's clinical history.

RESULTS

There were 120 participants (55.5% males), with a mean age 13.20+/-3.71 years and mean glycosylated haemoglobin (HbA1c) 7.36%+/-0.90. 52.5% of the sample used MGI systems. The caregivers of patients using MGI systems showed significantly higher scores (p<.05) regarding well-being, compared to the caregivers of patients not using this technology. In the former, a significant improvement (p<.05) in these variables with respect to the values prior to the beginning of their use was observed.

CONCLUSIONS

The use of MGI systems for diabetes self-management in our study led to a greater sense of well-being on the part of caregivers compared with before their introduction, as well as in comparison with those who continued to perform measurements using daily capillary glycemias.

Psychosocial Aspects of Diabetes Technology Use: The Child and Family Perspective

This article offers a systematic review of the literature on psychosocial aspects of technology use in children and adolescents with type 1 diabetes and their families, searching for relevant articles published the past 5 years. Topics included continuous subcutaneous insulin infusion, continuous glucose monitoring, predictive low-glucose suspend, and artificial pancreas systems. The review indicates there are positive and negative psychosocial aspects to diabetes technology use among youth and their families. Although consistent findings were revealed, contradictions exist. Discussed are recommendations for future research and implications for how health care providers can collaborate with families to discuss and manage diabetes technology.

Use of remote monitoring with continuous glucose monitoring in young children with Type 1 diabetes: the parents' perspective

AIM

Remote monitoring with continuous glucose monitoring (CGM) in children with Type 1 diabetes mellitus has recently become available, but little is known about caregivers' experiences of its use, particularly in younger children. The aim of this study was to explore parents' everyday experiences of using this technology.

METHODS

The parents of children with Type 1 diabetes diagnosed for > 1 year, aged 2-12 years were invited to participate in a semi-structured interview. Interviews were the second phase of a randomized cross-over study using standard insulin therapy with or without CGM and remote monitoring for two 3-month periods. Open-ended questions were used to explore parents' real-life experiences of the remote monitoring and CGM system. Interviews were analysed using thematic analysis.

RESULTS

Five themes related to remote monitoring emerged: (i) impact on sleep quality for the parents, (ii) peace of mind, (iii) impact on anxiety, (iv) freedom and confidence for the parents and children, and (v) impact on relationships. Furthermore, parents reported on themes related to CGM in general, such as better understanding of how to manage and control their child's diabetes and experiences related to physical or technical aspects.

CONCLUSION

Overall, parents of primary school children reported that using remote monitoring and CGM was a mostly beneficial experience. However, negative aspects within the themes were also reported. These findings will help to provide a structure to discuss parent and child expectations and provide targeted education at the start of using remote monitoring and CGM.

Improvement in Psychosocial Outcomes in Children with Type 1 Diabetes and Their Parents Following Subsidy for Continuous Glucose Monitoring

Background: In April 2017, the Australian Government announced the full subsidy of continuous glucose monitors (CGM) to children and young people <21 years with type 1 diabetes (T1D). This study aimed to evaluate the effect of CGM on psychosocial outcomes in a T1D pediatric population-based sample. Methods: Children with T1D, commencing CGM between June 2017 and January 2018, and their parents were recruited in a prospective cohort study in a tertiary pediatric hospital in Western Australia. Parents and children older than 12 years self-completed questionnaires at onset of CGM and 2 months later, on fear of hypoglycemia (FOH) and diabetes treatment satisfaction (DTS). Parents provided measures of sleep quality. Children completed the Gold hypoglycemia awareness score. Hemoglobin A1c (HbA1c) values were compared at baseline (BL) and follow-up (FU). Results: Sixty parents and 38 children provided measures at BL and FU. Parental total FOH decreased (mean score BL vs. FU; 50.0 vs. 44.3, P = 0.004) with reduction in the Worry subscore (28.2 vs. 24.2, P = 0.004). Furthermore, parental and child DTS increased. Parental sleep quality improved (P < 0.001) and overnight finger prick testing decreased (P < 0.001). Impaired hypoglycemic awareness decreased in children (26.3% vs. 10.5%, P = 0.031). HbA1c reduced from 8.4% (68 mmol/mol) to 8.1% (65 mmol/mol) (P = 0.036). Conclusions: Introduction of subsidized CGM showed early improvement in psychosocial and glycemic outcomes in patients and their families in Western Australia. Ongoing evaluation is essential to assess whether equitable access to CGM will translate to sustained benefits for Australian T1D pediatric patients.

The road from intermittently scanned continuous glucose monitoring to hybrid closed-loop systems. Part B: results from randomized controlled trials

BACKGROUND

Advances in diabetes technology have been exponential in the last few decades. With evolution in continuous glucose monitoring (CGM) systems and its progressive automation in control of insulin delivery, these advances have changed type 1 diabetes mellitus (T1DM) management. These novel technologies have the potential to improve glycated haemoglobin (HbA1c), reduce hypoglycaemic events, increase time spent in range and improve quality of life (QoL). Our aim was to evaluate the sustained effects in free-living unsupervised conditions of CGM systems (intermittently scanned and real time) and insulin delivery [from multiple daily injections, via sensor-augmented pump therapy and (predictive) low-glucose insulin suspension to hybrid closed-loop systems] on glucose control and QoL in adults and children with T1DM.

METHODS

We performed a systematic review of randomized controlled trials (RCTs), using PubMed and the Cochrane library up to 30 May 2019. Inclusion of RCTs was based on type of intervention (comparing glucose-monitoring devices and insulin-delivery devices), population (nonpregnant adults and children with T1DM), follow-up (outpatient setting for at least 8 weeks) and relevant outcomes [HbA1c, time in range (TIR), time in target, time in hypoglycaemia and QoL]. Exclusion of RCTs was based on intervention (exercise, only overnight use). The Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were used to score the quality of the papers and for the final selection of the articles.

RESULTS

Our search resulted in 214 articles, of which 19 were eligible. Studies on advanced use in adults and children with T1DM reported increased TIR (all 9 studies); decreased time in hypoglycaemia (13 out of 15 studies); lowered HbA1c levels (5 out of 15 studies); improved QoL (10 of 16 studies) and treatment satisfaction (7 studies).

CONCLUSIONS

Recent technologies have dramatically changed the course of T1DM. They are proving useful in controlling glycaemia in patients with T1DM, without increasing the treatment burden.

Real-Time Sharing and Following of Continuous Glucose Monitoring Data in Youth

BACKGROUND

Those caring for children and adolescents with diabetes often use glucose concentration and trending information in management decisions. Some continuous glucose monitoring (CGM) systems offer real-time sharing and monitoring capabilities through mobile apps carried by the person with diabetes and the caregiver(s), respectively. Few large studies have explored real-world associations between sharing and following, CGM utilization, and glycemic outcomes.

METHODS

We performed a retrospective evaluation of device usage and glycemic control in 15,000 youth ranging in age from 2 to 18 years by analyzing anonymized data that had been uploaded with a mobile app that provides optional sharing. The presence or absence of a real-time monitor (a "Follower") was established on 15 June 2018. Each day with ≥ 1 uploaded glucose values was counted as a day of device usage. Between-group glucose comparisons were made with two-sided Welch's t tests.

RESULTS

Overall, 94.8% of the population used the sharing feature and had at least one Follower. The mean numbers of Followers for patients aged 2-5, 6-12, and 13-18 years were 2.8, 2.8, and 2.4, respectively. In all three age categories, the presence of at least one Follower was associated with lower mean glucose values, more glucose values in the 70- to 180-mg/dL range, correspondingly fewer glucose values representing hypoglycemia and hyperglycemia, and significantly more device utilization.

CONCLUSION

Real-time sharing and following of CGM data are associated with improved device utilization and glycemic parameters. The observed association suggests either more timely interventions or higher levels of engagement among the caregivers or the youth with diabetes.

FUNDING

Dexcom, Inc.

Current Diabetes Technology: Striving for the Artificial Pancreas

Diabetes technology has continually evolved over the years to improve quality of life and ease of care for affected patients. Frequent blood glucose (BG) checks and multiple daily insulin injections have become standard of care in Type 1 diabetes (T1DM) management. Continuous glucose monitors (CGM) allow patients to observe and discern trends in their glycemic control. These devices improve quality of life for parents and caregivers with preset alerts for hypoglycemia. Insulin pumps have continued to improve and innovate since their emergence into the market. Hybrid closed-loop systems have harnessed the data gathered with CGM use to aid in basal insulin dosing and hypoglycemia prevention. As technology continues to progress, patients will likely have to enter less and less information into their pump system manually. In the future, we will likely see a system that requires no manual patient input and allows users to eat throughout the day without counting carbohydrates or entering in any blood sugars. As technology continues to advance, endocrinologists and diabetes providers need to stay current to better guide their patients in optimal use of emerging management tools.

The road from intermittently scanned glucose monitoring to hybrid closed-loop systems: Part A. Keys to success: subject profiles, choice of systems, education

Managing type 1 diabetes (T1DM) is challenging and requires intensive glucose monitoring and titration of insulin in order to reduce the risk of complications. The use of continuous glucose monitoring (CGM) systems, either flash or intermittently scanned glucose monitoring (isCGM) or real-time (RT) CGM, has positively affected the management of type 1 diabetes with the potential to lower HbA1c, enhance time spent in range, reduce frequency and time spent in hypoglycemia and hyperglycemia, lower glycemic variability, and improve quality of life. In recent years, both CGM and pump technology have advanced, with improved functional features and integration, including low glucose suspend (LGS), predictive low glucose suspend (PLGS), and hybrid closed-loop (HCL) systems. In this review, we highlight the benefits and limitations of use of isCGM/RT-CGM for open-loop control and recent progress in closed-loop control systems. We also discuss different subject profiles for the different systems, and focus on educational aspects that are key to successful use of the systems.