Position StatementPractical implementation, education and interpretation guidelines for continuous glucose monitoring: A French position statement
Introduction
The use by diabetes patients of real-time continuous interstitial glucose monitoring (CGM) or the FreeStyle Libre® (FSL) flash glucose monitoring (FGM) system is becoming more and more widespread and has changed patient, caregiver and researcher practices. Recommendations have been published recently for CGM use and data-reporting in clinical trials [1]. The working group bringing together a number of French experts [Conseil national professionnel d’endocrinologie, Diabète et maladies métaboliques (CNP-EDMM; National Professional Council of Endocrinology, Diabetes and Metabolic Diseases), Société francophone du diabète (SFD; Francophone Society of Diabetes), Société française d’endocrinologie (SFE; French Society of Endocrinology), Collège des diabétologues et endocrinologues des hôpitaux généraux (CODEHG; College of General Hospital Diabetologists and Endocrinologists), Groupe d’évaluation dans le diabète des implants actifs (EVADIAC; Evaluation Group of Active Implants in Diabetes), Fédération française des diabétiques (FFD; French Diabetes Federation) and Association d’aide aux jeunes diabétiques (AJD; Young Diabetics Help Association)] has proposed the present consensus to assist professionals in integrating these new technologies into their daily practice. Its main message is that the training of professionals and patient education are crucial to the success of CGM. The main recommendations of the working group are summarized in Table 1.
Section snippets
What is measurement of interstitial glucose?
CGM/FGM devices are based on the semi-continuous measurement of glucose in interstitial tissue. However, there is a discrepancy between the displayed value of interstitial glucose (IG) and that of capillary blood glucose due to the time delay of IG equilibration relative to blood glucose as well as the delay with measurements using subcutaneous electrodes due to converting the electrical signal into glucose levels and displaying the results on a screen [2], [3]. Furthermore, the relationship
The different devices currently available
Table S1 (see supplementary data associated with this article online) summarizes the main characteristics of the different systems that are currently available.
An alternative to self-monitoring of blood glucose (SMBG)
Glycaemic control of type 1 diabetes (T1D) retains priority over recommended objectives [7], as HbA1c improvement is limited by an increased risk of hypoglycaemia [8]. Although a relationship has been established between daily SMBG and HbA1c levels [9], < 30% of patients on a basal/bolus regimen perform the number of SMBG that meets the recommendation of at least four measurements per day [10]. In contrast, the IMPACT study [11], T1D patients using FSL performed an average of 15.1 ± 6.9 scans/day.
Metabolic and economic efficacy of CGM/FGM
Prerequisites
The following are necessary before the introduction of CGM:
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good manual dexterity;
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good cognitive ability;
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patient responsiveness with regard to therapeutic adjustments;
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patient commitment: as the efficacy of CGM correlates with sensor wearing time, patients must agree to use it permanently after being informed of the related conditions and usage constraints.
Initial therapeutic education
The use of CGM devices must be guided by structured therapeutic education, which is essential for the acquisition of technical skills as well
Organization of data collection (CGM/FGM)
For retrospective analysis of the data, it is important to train patients in prospective data collection. An exhaustive collection over a representational period (2 weeks) prior to consultation will make the retrospective analysis more effective for treatment adjustment. It will therefore be necessary to document meals (time, quantity of carbohydrates, daily food journal, photos…), insulin doses and timings; activities (hobbies, sports); medication treatments (acetaminophen) [25]; and sleep
Use of CGM/FGM in real time
Compared with standard SMBG, the management of insulin therapy is modified by the additional information (more values, changing trends) offered by CGM. This results in more frequent decision-making, leading to more rapid metabolic improvement [11], [18]. However, decision-making itself becomes more complex, requiring therapeutic education to limit the risks of glycaemic instability, anxiety and/or rejection of the technology.
Retrospective analysis and self-analysis of IG profiles
The retrospective analysis of data requires prior training of healthcare professionals (downloading and interpretation) and patient education [33] and is largely facilitated by collecting daily events (insulin doses and timing, food, physical activity…) in real time at least 1–2 weeks before consultation. Analysis of patterns has to take into account the personalized glycaemic goals of the patient, mutually established by both the patient and professional.
Structured analysis of the data must
Identification and correction of inappropriate uses and behaviors
Table 3 summarizes the causes to bear in mind when there are reliability problems with results, frequent misuse or insulin therapy effects on CGM/FGM.
Specific studies
The results of a dozen randomized controlled trials conducted in children (> 1000 children and adolescents with T1D) since 2006 show a remarkable effect on hypoglycaemic events [20], particularly with the TLGS function [13]. The benefits for HbA1c are significant, albeit slightly inferior to those obtained in adults. These benefits remain particularly dependent on device wearing time and disappear when its use is discontinued. The available data ‘in real life’ from large cohorts of young
Conclusion
CGM in real time is a considerable step towards refining useful tools for the daily management of diabetes. Maintained by caregiver and patient training, to which the present work aims to contribute, it allows an integrated mode of treatment that is a precursor to future advances towards an artificial pancreas. Indeed, we have already witnessed its first fruits with the availability of insulin pumps connected to glucose sensors capable of interrupting their output when hypoglycaemia occurs or
Funding
This work has been supported by the SFD, which covered scientific meeting travel expenses.
Disclosure of interest
S. Borot discloses congress invitations, honoraria and consultancies from Abbott, Animas/Johnson & Johnson, Medtronic, Roche.
P.-Y. Benhamou discloses congress invitations, honoraria and consultancies from Abbott, Animas/Johnson & Johnson, Dexcom, Insulet, Medtronic, Roche.
C. Atlan discloses congress invitations, honoraria and consultancies from Abbott and Medtronic.
E. Bonnemaison discloses congress invitations, honoraria and consultancies from Medtronic.
B. Catargi discloses congress
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