Continuous Glucose Monitoring in Type 2 Diabetes and Beyond

Importance: Continuous glucose monitoring (CGM), initially recommended primarily for people with type 1 diabetes, has rapidly expanded to patients with type 2 diabetes and, more recently, even to individuals without diabetes. This broadening use underscores the importance of critically examining the evidence supporting CGM across populations, clarifying where benefits are established, where they are modest, and where they remain uncertain. Observations: We reviewed systematic reviews and meta-analyses of randomized trials and clinical guidelines evaluating CGM use beyond type 1 diabetes, with particular attention to glycemic outcomes, hypoglycemia, patient-reported outcomes, and potential unintended consequences in nonpregnant adults. In adults with type 2 diabetes, evidence from randomized trials consistently demonstrated that CGM use was associated, on average, with a modest yet consistent reduction in hemoglobin A1c of approximately 0.3% compared with finger-stick monitoring or usual care; some patients benefited considerably more. Only limited and indirect evidence supported the adoption of CGM in people with type 2 diabetes not receiving glucose-lowering therapy or in those with prediabetes or obesity. Conclusions and Relevance: CGM should be deployed in response to a specific patient problem rather than as a default intervention. Deliberate, equitable deployment of CGM that is aligned with patient goals, clinical context, and system capacity will be necessary to ensure that those most likely to benefit are not left behind, while avoiding overuse in populations for whom benefit remains unproven.