Differences in Continuous Glucose Monitoring Metrics Between Prediabetes and Normoglycemia: A Systematic Review and Meta-Analysis

Background: Prediabetes often remains undiagnosed until it progresses to type 2 diabetes mellitus (T2DM), particularly among individuals with obesity or a family history of diabetes. Conventional tests, including fasting plasma glucose, hemoglobin A1c, and the oral glucose tolerance test, provide only static snapshots of glycemia and may fail to capture variability and postprandial excursions. Continuous glucose monitoring (CGM) offers dynamic insight into glucose regulation and may complement traditional diagnostic tools. Methods: This systematic review and meta-analysis evaluated differences in CGM-derived metrics between individuals with prediabetes and those with normoglycemia. PubMed, EMBASE, and CENTRAL were searched from inception to September 3, 2025 (PROSPERO: CRD42024608658). The primary outcome was the mean amplitude of glycemic excursions (MAGE); secondary outcomes included time above range, 24-hour mean glucose, coefficient of variation, and time in range. Sixteen studies met the inclusion criteria, and ten were included in the quantitative synthesis ( n = 1657). Results: Prediabetes was consistently associated with higher CGM values compared with normoglycemia: MAGE (mean difference [MD] = 9.41 mg/dL, 95% confidence interval [CI]: 4.31, 15.31), TAR% (MD = 5.68%, 95% CI: 1.04, 10.32), and 24-hour mean glucose (MD = 7.91 mg/dL, CI: 6.27, 9.55). Conclusions: These results provide the first quantitative evidence that CGM can discriminate between prediabetes and normoglycemia, supporting its potential as a complementary tool for refined metabolic risk assessment. Further prospective studies are needed to determine its predictive value for progression to T2DM.