Efficacy of continuous glucose monitoring in comparison to self-blood glucose monitoring in patients with type 2 diabetes mellitus under insulin treatment: a systematic review and meta-analysis

Diabetes Mellitus (DM) affects approximately 10.5% of the global population, necessitating effective glucose monitoring to mitigate complications. Self-monitored blood glucose (SMBG) lacks dynamic glycemic profiling, while continuous glucose monitoring (CGM) provides real-time/intermittent data. This review compares CGM and SMBG in insulin-treated type 2 diabetes (T2DM) patients. A systematic review and meta-analysis of randomized controlled trials (RCTs) from PubMed, Web of Science, and Scopus was conducted until May 2025 and included RCTs compared CGM with SMBG in terms of glycemic indices in adults with T2DM on insulin therapy (± oral agents), excluding studies < 6 weeks or non-insulin treatments. Meta-analysis using a random-effect model was performed. Thirteen RCTs (n = 1550) were included. CGM significantly reduced HbA1c (mean difference MD = − 2.78 mmol/mol, 95% CI: −4.68 to − 0.88) and TBR (MD = − 1.30%, 95% CI: −1.94 to − 0.65) versus SMBG. TAR reduction (MD = − 4.12%, 95% CI: −9.11 to 0.88) and TIR increase (MD = 4.04%, 95% CI: −0.09 to 8.17) were non-significant. Substantial heterogeneity in HbA1c (I²=89.66%) persisted despite subgroup analyses based on CGM type. CGM improves long-term glucose control (HbA1c) and hypoglycemia risk (TBR) in insulin-treated T2DM, supporting its clinical utility. Non-significant TIR/TAR trends may reflect limited statistical power. Future studies are warranted to delineate the outcome disparities between CGM and SMBG. Not applicable.