An Opportunity to Increase the Benefit of CGM Usage: The Need to Train the Patients Adequately

Introduction

The belief used to be that if patients with diabetes receive a continuous glucose monitoring (CGM) system, then glucose control will improve more or less automatically. Or, an even more extreme position was held by some that the availability of additional information about the current glucose levels and trend information will ensure that each patient has an optimal HbA1c when using a CGM system. A recent publication showing the analysis of a large registry with data from thousands of patients with type 1 diabetes in the United States initiated a lot of discussion.¹ The number of CGM users quadrupled from 7% to 30% and increased tenfold in younger children. However, Figure 2 in this publication shows that in spite of the larger availability of CGM the HbA1c values of the patients who participated in this registry in 2018 were higher than those patients who participated in 2012.¹ It is worth mentioning that Figure 3 in the same publication showed that CGM is associated with better HbA1c for both insulin pump and insulin injection users in the 2016 to 2018 survey. The point is that the increased use of a technology does not necessarily improve population outcomes, but, among those who do choose to use CGM, outcomes are better. This may likely be due to self-selection bias but could also be a direct effect of availability of the technology. In any case, smart use of CGM with appropriate training is undoubtedly better than no training.²

Continuous Glucose Monitoring Use Does Not Necessarily Lead to Better Outcomes

Investment into CGM usage does not result in an automatic improvement in glucose control. There are a number of reasons for this somewhat surprising and unexpected outcome, eg,

• - The patients who participated in the 2012 analysis were not actually the same ones that were in the 2018 analysis,

• - The number of patients represented at different data points differs considerably,

• - The CGM systems used were different in the two time periods,

• - These are self-reported data.

Probably, this outcome also reflects something else: providing real-time (rt)CGM systems per se (with only technical introduction) to the patients in this group was not sufficient. In order to optimize glucose control, patients must be trained adequately to transfer the wealth of information provided by CGM systems into meaningful therapeutic actions. However, it appears as if there is a difference in how the term “training” (or the term “education”) is used in the United States and Germany/Europe, which appears to be a source of misunderstandings when talking about “CGM training”:

1. In the United States, training usually means a lesson on how to use the device itself (= technical instruction; “Button pushing”), what the trend arrows mean, and how to set the alarms levels. Such training sessions (generally lasting only one or two hours) are performed one-on-one by salespersons of the manufacturer of the given rtCGM system or by trained nurses/ Certified Diabetes Educator (CDE)s. Most manufacturers also provide interactive tutorials online. Participation in such training sessions enables patients to insert their sensors adequately and use the given rtCGM system from a pure handling point of view.

2. In Germany, a CGM training program like SPECTRUM focuses on using the wealth of glucose information provided by this diagnostic option for optimization of diabetes therapy and not on the rtCGM system itself.³ This program was developed by a group of diabetologists, CDEs, and scientists without any financial support by any manufacturer. Participation in this program requires that the patients attend seven sessions in specialized diabetes practices, most often together with other patients. SPECTRUM includes some repetition until the patients fully understand the range of support rtCGM offers. Such an approach also reduces the risk of misinterpretation of the data and therapeutic errors. A French expert group recently published a consensus statement stating that patient education is crucial for patients to receive maximum benefit from the use of CGM technology.⁴

Educational Programs for CGM Users

The training is provided by “Diabetes Care and Education Specialists” (DCES) who participated in a respective training session; they must attend a weekend course to learn how to train patients with this program. In Germany, diabetologists regard “diabetes education” as mandatory; therefore, each practice offers a range of diabetes training programs for their patients and their CDEs are quite experienced in training patients.

A second education program named FLASH is also available for users of a CGM system that requires intermittent scanning (isc) users in Germany. It addresses emotional issues of using iscCGM but also provides training on how to make use of glycemic information to optimize insulin treatment. The development and evaluation was sponsored by the manufacturer of an iscCGM system. It is conducted as a group program by a certified DCES. Recently, the results of a study were published showing the benefits of participating in this education program with regard to an improved glycemic control, reduced diabetes distress, and higher satisfaction with the glucose monitoring system.⁵

A recently reported study from Korea recently found that a diabetes education program for interpreting CGM readings using a pattern management approach resulted in improved self-care behaviors and self-efficacy (a belief in the capacity to execute behaviors necessary to produce specific performance attainments) for diabetes management.²

Guidelines

A number of national and international guidelines recommend the usage of rtCGM systems in patients with type 1 diabetes to support patients’ in keeping their blood glucose levels within the target range (time in range) of 70 to 180 mg/dL and to prevent acute deteriorations into the hypo- or hyper-glycemic range, ie, to improve treatment safety and efficacy.^6,7 These guidelines are based on a considerable number of clinical trials performed with different rtCGM systems and subsequent meta-analyses.^8-11 It is not clear how much attention was paid in these studies to adequate training of study participants according to the European meaning of this word, as outlined above; at least in most publications, nothing or very little is stated about the training efforts devoted to the study participants. One might argue that if in such studies an improvement in HbA1c concentrations was seen without providing such formal training, then why bother with doing so. Subsequently, the manufacturers of rtCGM systems have frequently not regarded additional training (more than the technical training) as relevant. However, the question is, how much better the effect would have been in such trials—but also in daily life (see above)—what if the patients would have been more intensively trained in how to make use of all the information provided by the given rtCGM system(s) to optimize their diabetes therapy? As one example from a current rtCGM study showed, the quality of glucose control when using an rtCGM system is improved; however, it is not optimal. In the DIAMOND study, 158 subjects with type 1 diabetes treated with multiple daily injections were randomized to the Dexcom G4 Platinum rtCGM system or their current diabetes care.¹² The mean HbA1c concentration was 8.6% at baseline for both groups and rtCGM was used ≥6 days a week in 93% of the patients. Results showed that rtCGM users reduced HbA1c concentrations by 0.6% in comparison with the subjects in control group. However, at the six-month follow-up, 62% of rtCGM users had still a HbA1c value ≥7.5% and only 18% of study participant meet ADA HbA1c target <7.0% at this time point. Time spent in range (70-180 mg/dL) was only increased by 11.5% from 660 to 736 minutes and time in hyperglycemia reduced by 8% from 687 to 638 minutes. Compared with this was time spent at glucose levels <70 mg/dL decreased by 34% from 65 to 43 minutes in the rtCGM group. This might indicate that reduction of hypoglycemia by responding to hypoglycemic alerts might be easier than reduction of hyperglycemia, since this requires more complex skills.

In this study, CGM was found to be cost-effective at the willingness-to-pay threshold of $100 000 per quality-adjusted life year attained.¹³ In the DIAMOND study, the intervention subjects received a minimum of rtCGM training only. They received one page of instructions about how to make use of the information provided by the rtCGM system. How much better the outcome of this study (and many others) might have been with a more detailed rtCGM training program for the intervention subjects? It would be worth performing a detailed literature review of CGM studies performed with respect to the training efforts in these. Clearly, a definitive answer to the question raised is possible only when an adequately performed clinical trial is performed. In such a trial, one group of subjects would be “adequately” trained and the other not trained at all while using the same CGM system.

An analogy to the situation with CGM systems is self-monitoring of blood glucose (SMBG) testing: patients have better results when they perform structured testing than when they are simply given numbers to work with but no instructions on what to do with these numbers.¹⁴ There were many discussions for many years about the impact of adequate training on glucose control with SMBG. Merely measuring blood glucose levels without linking these results to therapeutic actions has not been shown to be beneficial. However, when structured responses to the SMBG results are provided, then there is benefit.^15,16

Features of Successful rtCGM Programs

Patient education about how to interpret CGM results is necessary to avoid unnecessary concern about borderline “normal” readings (which should be individualized) or patterns. These concerns can lead anxious individuals to unnecessarily seek medical attention and additional testing. This outcome can compromise appropriate allocation of scarce medical resources.¹⁷

Several important requirements must be considered for the successful use of rtCGM or iscCGM systems with respect to optimization of glucose control as well as the quality of life and patient satisfaction (as demonstrated by patient reported outcome surveys). Successful rtCGM or iscCGM programs demonstrate

• realistic patient expectations of the time and efforts needed to learn the new therapeutic concept and its integration into everyday life;

• the will to “rethink” about treatment routines used until now in diabetes therapy;

• adequate reactions to hitherto undetected glucose fluctuations and rational adjustments of therapy to correct hypo- or hyperglycemic situations;

• an understanding of the time delay between blood glucose and tissue glucose levels;

• alarm settings adapted to the individual metabolic situation, which warn of risks without sounding unfavorable false positive alarms in everyday life;

• the ability to perform a structured analysis and interpretation of the glucose data to optimize diabetes therapy, based on the patient’s individual treatment goals agreed with the treating physician and CDA or in general HCP;

• age-related explanations of rtCGM systems for younger children, inclusion of other caregivers in childcare facilities, and appropriate alarm settings that do not cause children to feel unsafe.

In a sense, patients have to forget some things that they had learned previously when using SMBG. The much higher amount of data (for some patients it can be a data overload) requires to learn of how to react to the constant data availability and not overreact to it. Continuous glucose monitoring provides a lot of information, but does not result automatically in better and safer glycemic control.

Conclusion

Coming back to the starting point, a clinically relevant improvement in glucose control can also probably be achieved in the United States in case patients participate in adequate CGM education programs. These programs should not be one-time events, but should accompany patients for some time during their learning process when using CGM systems. In practice, there is a need to train patients with diabetes to enable them to take full advantage of what technology provides. Our suggestion is that additional research comparing training programs and their impact on outcomes should be performed to be able to better define the minimum requirements for optimum deployment of CGM systems. Now, however, it is time to conduct a formal study that looks at outcomes both without and with various types of educational programs to see how much more clinical education improves outcomes.