Continuous Glucose Monitoring in Children with Type 1 Diabetes Improves Well-Being,Alleviates Worry and Fear of Hypoglycemia

Introduction

Type 1 diabetes mellitus (T1DM) in children is a common condition that continues to pose a serious health risk worldwide. The diagnosis and ongoing burden of disease causes significant psychological stress in families and considerable long-term complications if good metabolic control is not achieved. ¹ Even when the glycated hemoglobin (HbA_1c) is below target, the blood glucose levels in any patient with T1DM can be variable. ² Dysglycemia in the form of both hypoglycemia and hyperglycemia is known to have a significant short-term impact on the developing brain, affecting the activity, survival, and function of neural cells. ³ In children, the effect of seizures caused by severe hypoglycemia has been shown to have a transient impairment in neuropsychological profile with effect on memory, visuospatial reasoning, and mental flexibility. ⁴ At worst, an acute complication of dysglycemia can lead to sudden death, described as the “dead-in-bed” syndrome. ⁵ Studies have shown that prolonged QT interval caused by undetected severe nocturnal hypoglycemia and autonomic neuropathy is possibly the cause of 2%–14% of deaths in patients with type 1 diabetes. ⁶ One of the factors imperative to reducing glycemic variability is appropriate adjustment to insulin dosing, which is achieved by continuous monitoring of blood glucose levels and trends.

The aim of diabetes management is to reduce the risk of diabetes-related complications and to achieve an improved quality of life for patients and their families through optimum metabolic control. However, tighter metabolic control also carries an increased risk of hypoglycemic episodes, ¹ and it is postulated that families with a high fear of hypoglycemia and its consequences run blood sugars higher to avoid this. In adults, fear of hypoglycemia is common, ⁷ with it being classed as one of the most feared complications of T1DM. ⁸ It has been found to be strongly linked to high frequency of hypoglycemic episodes, anxiety in an adult population, female gender, higher age, and longer duration of T1DM in adolescents. ^9,10 This finding can be extrapolated and applied to children and young people with T1DM as well as their parents, both equally important, as parental fear of hypoglycemia influences the management of the child with T1DM and is also likely to influence the child's fear of hypoglycemia. ¹¹ Previous studies have reported fear of hypoglycemia as a term used to describe severe anxiety-like symptoms related to glucose management as well as the use of hypoglycemic avoidance behaviors, and Patton et al. ^12,13 reported fear of hypoglycemia and anxieties in up to 60% of parents of young children based on self-report using the hypoglycemia fear survey for parents of young children (HFS-P) validated survey.

Self-monitoring of blood glucose (SMBG) is an important part of diabetes management ¹⁴ but only provides a snapshot view of the blood sugar at that point in time. From a one-off reading, it is impossible to see what the trend in the blood sugar is and to obtain a trend, a series of readings are needed. Obtaining such data through SMBG can be an issue in children who are needle phobic, or those who generally have poor compliance as they may be less likely to check their blood glucose levels frequently throughout the day. ¹⁵

Continuous glucose monitoring (CGM) provides real-time measurement of users' glucose levels. The advantage of CGM is the availability of constant information about glucose levels, as well as trends, which help to predict hyperglycemia and hypoglycemia and to adjust the insulin doses accordingly. National Institute for Health and Care Excellence guidelines in the United Kingdom recommend that CGM be offered to children with T1DM that have frequent severe hypoglycemia, or, impaired awareness of hypoglycemia associated with adverse consequences, or, inability to recognize, or communicate about, symptoms of hypoglycemia. ¹⁶ Recent studies have shown that CGM technology can reduce HbA_1c without increase in the risk of hypoglycemia. ¹⁷ CGM can be advantageous in this population of patients by allowing families to adjust insulin doses and it has been shown in adults to achieve improved control with reduced risk of hypoglycemia, while simultaneously improving confidence and reducing fear. ^18,19 However, there is little research describing this advantage in children and its benefits over SMBG in improving control in this population, and consequently, in the United Kingdom, there is limited funding for CGM.

Methods

In this study, we have evaluated the effect of CGM on the metabolic control and fear of hypoglycemia and worry scores on a cohort of children with T1DM who were funded to use CGM for a 12-month period. This study was conducted within a pediatric diabetes unit in a large district general hospital in the northwest of the United Kingdom.

Sixteen children up to the age of 18 years, who had used CGM (Dexcom G4) for at least 12 months were included in the study. All patients were on pump therapy before starting CGM. All participants received education on CGM use before commencement and were instructed to wear the CGM all the time. Data were collected for the 12-month period beginning from when the CGM was commenced as part of an audit. Information was collected for demographics and HbA_1c at 0, 3, 6, 9, and 12 months post-CGM use.

Children aged >12 years independently completed the hypoglycemia fear survey (HFS). ⁷ Parents of all the patients were asked to complete a modified version of the HFS-P ¹² The HFS-P is a reliable and valid measure of fear of hypoglycemia adapted from an existing adult questionnaire, the HFS. ^13,20 HFS-P is designed to assess fear, anxieties, avoidance behaviors, and worry associated with hypoglycemia in parents and carers of younger children with diabetes. ²⁰ The HFS-P is a validated 25-item questionnaire that examines fear of hypoglycemia in parents of preadolescent children. Similar to the original HFS from which the HFS-P was modified, the HFS-P has two subscales that measures parents' behaviors related to preventing an episode of hypoglycemia and their worry and anxieties that their child may experience a hypoglycemic episode. Similar to the HFS scores, HFS-P yields a subscale score for each of the behavior and worry scales and a total score, with higher scores indicating greater fear of hypoglycemia. For items in HFS that originally sought to measure behavior or worry specific to hypoglycemia when children were alone, in the HFS-P survey, the phrase “away from me and in someone else's care” was added to the item, as it was expected that very young children were never left alone.

Consent was obtained to take part in this audit survey. As part of a routine national annual audit review, a psychological assessment is routinely undertaken as part of the service evaluation as well as monitoring. HbA_1c is also monitored three monthly as part of a national audit process for children with diabetes within the United Kingdom.

Results

Sixteen patients received CGM for at least 12 months. Eight of these patients were boys. Their ages ranged from 2 to 17 years (median age of 13.5 years). Mean duration of diabetes diagnosis was 7.6 years (range 3–12.4 years). All patients were on an insulin pump at the time of CGM commencement. There were reported issues with compliance in 58% of patients. Five patients used the CGM sensor intermittently after 8 months of continuous usage reporting up to 1 week per month of not using the CGM due to sensor issues. Two patients reported problems with allergy to plaster and seven patients reported that the CGM device was not sticking very well to the skin, requiring other adhesives. Overall, there were no episodes of severe hypoglycemia needing third-party assistance or hospitalization during this study period.

Discussion

This study was conducted in a pediatric population and found no significant improvement in HbA_1c for a 12-month period of CGM usage. This is not surprising as studies involving children with CGM devices have not consistently shown benefit on long-term metabolic control. ²¹ In our cohort, we found that after 8 months of CGM use, up to 58% of children and adolescents were not using their CGM sensors routinely. This could possibly be the reason for deterioration in control after initial improvement. Yeh et al. ²² found in their review that glycemic control improvement was seen in patients with high levels of sensor adherence. In 2009, The Juvenile Diabetes Research Foundation CGM study group found no difference in HbA_1c for 8- to 14-year olds when compared with controls but reported improvement in control for adults. ²³ They also found a positive correlation between an increase in age and CGM usage, with adult patients (aged >25 years) being most likely to use CGM on 6 or more days per week. Similarly, this association between age of patient and compliance with CGM usage was reported by De Bock et al., ²⁴ as well as a decrease in compliance across all age groups after 9 and 11 weeks after commencement. De Bock et al. ²⁴ showed that although patterns of CGM usage was individual to each patient, in general, despite a reduction in HbA_1c, children and adolescents may not be willing to wear a device as often, or for prolonged periods of time as is required to result in consistently achieving improved glucose metabolism.

Lawton et al.'s ²⁵ recent exploratory qualitative study provided an understanding of participants' experiences about using CGM and reports that CGM can be an empowering and motivational tool that enables participants to fine-tune and optimize their blood glucose control reducing hypo- and hyperglycemic excursions and thereby improving their well-being. A randomized controlled trial published in 2012 by Mauras et al. ²⁶ investigated the efficacy and safety of CGM use in a population of patients aged 4–10 years with T1DM. ²⁶ In contrast with adult studies and similar to our results, they did not find any improvement of long-term metabolic control. They found that those who used the CGM reported high parental satisfaction and an improved knowledge of glycemic variability but hypothesized that an unremitting high parental fear of hypoglycemia formed a barrier to improving long-term glycemic control. Similarly, they also found issues with compliance, with usage of CGM decreasing over time, and consequently affecting their results. In comparison with the findings regarding fear of hypoglycemia from Halford et al., ²⁷ studies conducted with adult participants showed positive improvements in both fear of hypoglycemia levels and quality of life. A study by Vesco et al. ²⁸ reported that improvements in adaptive behaviors and attitudes that enhance resilience in living with diabetes were associated with reductions is diabetes distress in both parents and adolescents.

Recent studies with sensor-augmented pumps have also shown reduction in hypoglycemia, but those results are not transferable to our population as all our patients wore stand-alone pumps with CGM devices, ²⁹ and it was difficult to capture the real incidence of hypoglycemia before using the CGM and compare it with after CGM use. Although our sample size was small, the study was able to show that the CGM device gave parents and children the confidence to alter treatment regimens and CGM improved their anxieties, fear, and worry.

The study highlights the importance of education and training of parents and children when using these complex technologies so that maximum benefit is obtained. The need for patient training and selection when selecting CGM therapy has been identified. The UK Association of Children's Diabetes Clinicians group has recently published guidelines for the use of CGM in clinical practice, ³⁰ which highlights the need for appropriate patient selection and indications when withdrawal of CGM systems may be justified. Reduced fear of nocturnal hypoglycemia along with reduced frequency of hypoglycemic episodes were among the beneficial psychological effects reported in a qualitative analysis by 52% of adult patients and parents of children with T1DM who had used CGM. ³¹ Within our study population, use of CGM significantly decreased the level of parental fear of hypoglycemia (P < 0.001). We also found that for the patients aged 12 years and over who completed their own surveys, fear of hypoglycemia was also significantly reduced (P = 0.003) but less so than for their parents where the statistical significance was greater (P < 0.001). This subtle difference in the significance in the scores from the parents and young people may be due to differences in the way that adolescents view the impact of T1DM on their daily life, a concept explored by Markowitz et al. ³² who reported that there was a very different psychosocial effect of T1DM on adults, adolescents, and their parents. These are important findings as they signify not only as potentially improving HbA_1c through increased awareness of glycemic variability, but also CGM can be utilized to allay both parental and the young person's fear of hypoglycemia, reduce the burden of psychological distress, and hence engage the family in behaviors that will avoid blood glucose levels being run higher than is necessary.

Limitations of this study include the small sample size. The outcomes evaluated as part of the audit was well-being, hypoglycemic fear, and worry scores validated using the HFS and HFS-P surveys. All patients were reviewed in clinic every 3 months where their HbA_1c was obtained; however, details related to specific CGM data such as time in range were not obtained. The authors note that future larger prospective studies should take this into account.

Conclusion

This study shows that CGM significantly reduces worry and fear of hypoglycemia and improves the well-being of children with T1DM and their parents. It builds upon the current limited evidence from adult research that CGM is a useful tool to improve psychological well-being, glycemic control, and importantly reduces the fear in both parents and children with T1DM. Larger studies focusing on psychological aspects of CGM use are warranted.