Efficacy of Continuous Glucose Monitoring in Improving Glycemic Control and Reducing Hypoglycemia: A Systematic Review and Meta-Analysis of Randomized Trials

Abstract

Abbreviations: (CGM) continuous glucose monitoring, (CI) confidence interval, (HbA1c) hemoglobin A1c, (RCT) randomized controlled trial, (RR) relative risk, (SMBG) Abstract Objective:We conducted a systematic review and meta-analysis to assess the efficacy of continuous glucose monitoring (CGM) in improving glycemic control and reducing hypoglycemia compared to self-monitored blood glucose (SMBG). Methods:We searched MEDLINE, EMBASE, Cochrane Central, Web of Science, and Scopus for randomized trials of adults and children with type 1 or type 2 diabetes mellitus (T1DM or T2DM). Pairs of reviewers independently selected studies, assessed methodological quality, and extracted data. Meta-analytic estimates of treatment effects were generated using a random-effects model. Results:Nineteen trials were eligible and provided data for meta-analysis. Overall, CGM was associated with a significant reduction in mean hemoglobin A1c [HbA1c; weighted mean difference (WMD) of -0.27% (95% confidence interval [CI] -0.44 to -0.10)]. This was true for adults with T1DM as well as T2DM [WMD -0.50% (95% CI -0.69 to -0.30) and -0.70 (95% CI, -1.14 to -0.27), respectively]. No significant effect was noted in children and adolescents. There was no significant difference in HbA1c reduction between studies of real-time versus non-realtime devices (WMD -0.22%, 95% CI, -0.59 to 0.15 versus -0.30%, 95% CI, -0.49 to -0.10; p for interaction 0.71). The quality of evidence was moderate due to imprecision, suggesting increased risk for bias. Data for the incidence of severe or nocturnal hypoglycemia were sparse and imprecise. In studies that reported patient satisfaction, users felt confident about the device and gave positive reviews.

Continuous Glucose Monitors

“…CGM has had a significant impact on the care we provide for our insulin-dependent patients. 6 For the first time patients have a degree of security that they will be alerted to high or low glucose levels as these changes occur, potentially before they become symptomatic, allowing corrective action to be taken promptly. 6 …”

“…6 This is noted despite repeated concerns expressed in the literature over the accuracy of CGM devices when compared to home glucometers. 21 Many clinicians have questioned this focus on the numerical glucose value and accuracy, particularly given the inherent inaccuracies in SMBG.…”

2017 National Standards for Diabetes Self-Management Education and Support

“…Moving beyond static lecture methodology, incorporating meaningful discussions to address individual needs, and using interactive teaching styles are required. Incorporating PGHD, especially blood glucose and/or continuous glucose monitoring data, into decision making individualizes self-management and empowers participants to fully engage in personal problem solving to change behavior and improve outcomes (16,(142)(143)(144). There is strong evidence that incorporating text messaging into DSMES interventions improves engagement and outcomes (25,(145)(146)(147).…”

Improving the Clinical Value and Utility of CGM Systems: Issues and Recommendations

“…A number of formal summaries of the CGM literature have been conducted (25)(26)(27)(28)(29)(30)(31)(32). Although this suggests that the field is coming of age, review of the existing evidence base has generated diverse conclusions, ranging from "limited evidence" (Cochrane review) (25) to fully supportive (28)(29)(30).…”