Continuous glucose monitoring for diabetes prevention in adults with prediabetes: a scoping review

Background Prediabetes affects a rapidly growing proportion of adults worldwide (IDF Diabetes Atlas 2024: 12.0% impaired glucose tolerance; 9.2% impaired fasting glucose). Continuous glucose monitoring (CGM) offers a more granular window into glycemic patterns than intermittent testing, and its use in prediabetes research has grown substantially, but this literature has not been comprehensively mapped. Objective To systematically map the extent, range, and nature of peer-reviewed literature on CGM use in adults with prediabetes, following a pre-registered protocol. Methods PubMed was searched in June 2026 (436 records), followed by a supplementary Europe PMC and Scopus check in October 2026. After AI-assisted first-pass title/abstract screening (with post hoc human re-screening of random samples) and independent two-reviewer eligibility assessment against Population–Concept–Context criteria (adults 18 and older with prediabetes; any rtCGM/isCGM use; no design restriction), 44 PubMed studies were included. The supplementary search added 4, a post hoc re-screening audit reinstated 1, and 1 was excluded on closer verification, giving 48 included studies, all with extracted data. No meta-analysis or formal quality appraisal was performed; studies were narratively synthesized into five pre-specified categories. Results Fifteen studies characterized CGM-derived glycemic metrics, showing graded worsening of glycemic control and variability across the normoglycemia–prediabetes–diabetes continuum. Twenty-nine studies evaluated CGM-guided interventions, which produced CGM-detectable improvements in glycemic variability or time-in-range that did not consistently translate into significant HbA1c or fasting glucose change. Three studies addressed screening/diagnosis, including a large cohort (n=8,315) in which single-timepoint fasting glucose resulted in different glycemic classification when repeated CGM-derived measurements were considered. One study addressed broader metabolic/complication risk, and none addressed CGM-based prediction of progression from prediabetes to type 2 diabetes. Conclusion CGM provides a more granular, continuous picture of glycemic dysregulation in prediabetes than intermittent testing. Interventions used CGM either as a real-time feedback tool or as a blinded outcome measure of non-CGM interventions, with CGM-detectable glycemic improvement in both, though durable biomarker translation remains inconsistent. CGM-based prediction of progression to diabetes is an unaddressed evidence gap; CGM’s role in screening/diagnosis and complication-risk assessment also warrants more research. Systematic review registration https://doi.org/10.17605/OSF.IO/QSXK9 , identifier 10.17605/OSF.IO/QSXK9.