Efficacy and Safety of Continuous Glucose Monitoring and Intermittently Scanned Continuous Glucose Monitoring in Patients With Type 2 Diabetes: A Systematic Review and Meta-analysis of Interventional Evidence

Background: Traditional diabetes self-monitoring of blood glucose (SMBG) involves inconvenient finger pricks. Continuous glucose monitoring (CGM) and intermittently scanned CGM (isCGM) systems offer CGM, enhancing type 2 diabetes (T2D) management with convenient, comprehensive data.

Purpose: To assess the benefits and potential harms of CGM and isCGM compared with usual care or SMBG in individuals with T2D.

Data sources: We conducted a comprehensive search of MEDLINE, Embase, the Cochrane Library, Web of Science, and bibliographies up to August 2023.

Study selection: We analyzed studies meeting these criteria: randomized controlled trials (RCT) with comparison of at least two interventions for ≥8 weeks in T2D patients, including CGM in real-time/retrospective mode, short-/long-term CGM, isCGM, and SMBG, reporting glycemic and relevant data.

Data extraction: We used a standardized data collection form, extracting details including author, year, study design, baseline characteristics, intervention, and outcomes.

Data synthesis: We included 26 RCTs (17 CGM and 9 isCGM) involving 2,783 patients with T2D (CGM 632 vs. usual care/SMBG 514 and isCGM 871 vs. usual care/SMBG 766). CGM reduced HbA1c (mean difference -0.19% [95% CI -0.34, -0.04]) and glycemic medication effect score (-0.67 [-1.20 to -0.13]), reduced user satisfaction (-0.54 [-0.98, -0.11]), and increased the risk of adverse events (relative risk [RR] 1.22 [95% CI 1.01, 1.47]). isCGM reduced HbA1c by -0.31% (-0.46, -0.17), increased user satisfaction (0.44 [0.29, 0.59]), improved CGM metrics, and increased the risk of adverse events (RR 1.30 [0.05, 1.62]). Neither CGM nor isCGM had a significant impact on body composition, blood pressure, or lipid levels.

Limitations: Limitations include small samples, single-study outcomes, population variations, and uncertainty for younger adults. Additionally, inclusion of <10 studies for most end points restricted comprehensive analysis, and technological advancements over time need to be considered.

Conclusions: Both CGM and isCGM demonstrated a reduction in HbA1c levels in individuals with T2D, and unlike CGM, isCGM use was associated with improved user satisfaction. The impact of these devices on body composition, blood pressure, and lipid levels remains unclear, while both CGM and isCGM use were associated with increased risk of adverse events.