Background and Aims: The glycemic effects of continuous glucose monitoring (CGM) are well established in type 1 diabetes but less clear in type 2 diabetes. We aimed to comprehensively evaluate the effect of CGM on glycemic control compared to self-monitoring of blood glucose in adults with type 2 diabetes.

Methods: A systematic review of Embase, MEDLINE, Web of Science, Scopus, and Clinicaltrials.gov was conducted until May 2, 2023. We included randomized controlled trials comparing real-time CGM (rtCGM) or intermittently scanned CGM (isCGM) with self-monitoring of blood glucose in adults with type 2 diabetes. Change in HbA1c and other glycemic parameters were extracted.

Results: We could include 12 trials (total n=1248 participants): eight on rtCGM and four on isCGM. CGM use (rtCGM or isCGM) was associated with a mean HbA1c reduction of -0.31% [-3.39 mmol/mol] (95%CI:-0.43 to -0.19) and low heterogeneity (I²=15%) compared to self-monitoring of blood glucose. Results were consistent for users of insulin (MD:-0.30% (95%CI:-0.57 to -0.03), both insulin or oral agents (MD:-0.33%, 95%CI:-0.56 to -0.11), and oral agents only (MD:-0.29%, 95%CI:-0.49 to -0.10). CGM also improved other glycemic parameters, including time in range (+6.4%, 95%CI:+2.5% to +10.3%), time below range (-0.7%, 95%CI:-1.2% to -0.1), time above range (-5.9%, 95% CI -10.9% to -0.8%) and glycemic variability (-1.5%, 95%CI:-2.9% to -0.01%).

Conclusions: CGM use is associated with a relatively modest, but clinically relevant improvement in glycemic control type 2 diabetes. CGM can play a role in the glycemic management of type 2 diabetes.