Comment to ‘Minimum expectations for market authorization of continuous glucose monitoring devices in Europe—“ eCGM ”’

We read the recent publication by Mathieu et al., ‘Minimum expectations for market authorization of continuous glucose monitoring devices in Europe “eCGM” compliance status’ with great interest.1 We support the authors' intent to enhance the safety and effectiveness of continuous glucose monitoring (CGM) devices for people with diabetes. We also share the concern regarding the market entry of CE-marked CGM systems that may underperform, particularly at the extremes of glycaemia. At the same time, we would like to offer an alternative perspective on their proposed approach. While we appreciate the rationale behind adopting the FDA's integrated CGM (iCGM) criteria, we believe there are other viable pathways to establishing appropriate performance expectations for CGM systems in Europe (eCGM). In this letter, we aim to constructively share the rationale behind our concerns and offer an alternative interim standard for consideration. We believe the iCGM criteria may not be uniquely suited for this purpose, as they were originally developed to support interoperability rather than to function as a standalone safety or performance standard. For example, there are instances where iCGM-compliant systems were contraindicated for use with AID systems.2 Moreover, both real-world evidence and clinical trial data involving hundreds of thousands of users demonstrate that non-iCGM systems can be highly effective and safe.3 A second consideration is that the FDA offers alternative pathways for CGM approval, as illustrated by the recent approval of the Simplera CGM, which do not require adherence to the iCGM criteria.4 Such pathways are not proposed in the paper by Mathieu et al. for Europe, which could unintentionally create barriers to access safe and effective CGM devices. A working group of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), dedicated to this topic, similarly noted that ‘this approach could create an environment where market access might be limited to companies with prior FDA approval’ and questioned why a CGM system, supported by robust safety and efficacy data from rigorously designed studies, should not be eligible for CE marking, even without prior FDA approval.5 Thirdly, the IFCC working group highlighted that ‘some crucial aspects of the proposed eCGM requirements are incomplete and lack the necessary clinical and scientific substantiation to ensure a consistent and meaningful assessment of CGM performance’. In response to the call by Mathieu et al. for interim CGM performance standards, we would like to propose an alternative approach (Table 1) that has been clinically validated and demonstrated to ensure safe and effective outcomes in over 100 000 users.2 The key distinction between our proposed interim standard, and that of Mathieu et al. is the incorporation of a clinical rationale into the performance criteria ensuring alignment with real-world safety and efficacy outcomes. Specifically, we propose replacing the criteria based on ‘CGM 180 mg/dL ±40%’ with a single criterion focused on the percentage of points falling in the A and B regions of the Consensus Error Grid.6 Other notable differences include the addition of a specific criterion for performance on the first day of wear, when sensors often underperform, and a consistent rule for pairing CGM glucose values with reference glucose values. For instance, we propose always pairing the FDA approved blood glucose analyser reference value with a future CGM glucose reading recorded within 5 min of the reference value. These criteria were derived under the assumption that any CGM system fulfilling them will be similarly safe and effective as that CGM system. To conclude, we would like to once again express our appreciation to the authors, and to the IFCC working group, for their continued commitment to enhancing the quality and safety of CGM systems. Emphasising our support of the initiative to create a performance standard for CGM and potentially ISO standard. We believe that collaborative efforts, including the active involvement of industry experts, are essential to advancing this important field in a way that prioritises people with diabetes safety and improves health outcomes. The authors have nothing to report. All authors are employees of Medtronic. The peer review history for this article is available at https://www.webofscience.com/api/gateway/wos/peer-review/10.1111/dom.70072. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.