Systematic Review and Meta-Analysis of Subcutaneous CGM in Elective Surgery

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medRxiv Published May 8, 2026 Medically reviewed May 11, 2026 Study authors: Oliveira Andrade, L. J. d.; Matos de Oliveira, G. C.; Vinhaes Bittencourt, A. M.; Mattos Salles, O. … DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Consider subcutaneous CGM during elective surgery to improve glucose monitoring, but note reduced accuracy in cardiac procedures with hypothermia.

This systematic review and meta-analysis evaluated subcutaneous continuous glucose monitoring (CGM) compared with conventional point-of-care monitoring in 557 adults undergoing elective surgery under general or neuraxial anesthesia. The primary outcomes were pooled mean absolute relative difference (MARD) and time in range (TIR, 70/180 mg/dL).

The pooled MARD was 14.1% (95% CI 11.3/16.9%; I2=78%), indicating moderate accuracy. In non/cardiac surgery, MARD was 12.7%, while in cardiac procedures with hypothermia, MARD was significantly higher at 19.2% (p=0.03). CGM use was associated with a 14.9 percentage point improvement in TIR (95% CI 7.2/22.6; p<0.001). Clinically significant hypoglycemia was detected in 43% of patients, and sensor availability exceeded 96%.

No serious device-related adverse events were reported, though other safety outcomes were not detailed. The authors did not explicitly list limitations, but the high heterogeneity (I2=78%) for MARD suggests variability across studies. The review supports the potential integration of subcutaneous CGM into anesthetic management, though accuracy concerns in hypothermic cardiac procedures warrant caution.

Study Details

Study typeSystematic review

Sample sizen = 557

EvidenceLevel 1

PublishedMay 2026

View Original Abstract ↓

Introduction: Intraoperative glycemic dysregulation, including unrecognized hypoglycemia and stress/induced hyperglycemia, is common during elective surgery. Conventional point/of/care (POC) monitoring provides only intermittent measurements, limiting the anesthesiologists ability to detect rapid glucose fluctuations. Continuous glucose monitoring (CGM) enables real/time, trend/based assessment, potentially shifting intraoperative glycemic management from reactive to proactive. Objective: To meta/analyze the analytical accuracy, intraoperative glycemic efficacy, and feasibility of subcutaneous CGM in adults undergoing elective surgery, informing anesthesiology practice. Methods: This systematic review and meta/analysis followed the PRISMA 2020 statement. Searches were conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials from January 2010 to May 2025. Eligible studies included randomized controlled trials and prospective cohorts of adults undergoing elective surgery under general or neuraxial anesthesia using subcutaneous CGM. Primary outcomes were pooled mean absolute relative difference (MARD) and time in range (TIR, 70/180 mg/dL). Random/effects models were applied. Results: Ten studies (3 RCTs, 7 cohorts; N=557) were included. Pooled MARD was 14.1% (95% CI 11.3/16.9%; I2=78%), lower in non/cardiac surgery (12.7%) than cardiac procedures with hypothermia (19.2%; p=0.03). CGM improved TIR by +14.9 percentage points (95% CI 7.2/22.6; p<0.001). Clinically significant hypoglycemia was detected in 43% of patients, all missed by POC. Sensor availability exceeded 96%, with no serious device/related events. Conclusion: Subcutaneous CGM provides acceptable intraoperative accuracy and improves glycemic control, supporting its integration into anesthetic management. Keywords: Continuous glucose monitoring; intraoperative glycemic control; anesthesia; perioperative medicine.