Continuous Glucose Monitoring Use Leads to Reduction in Glycosylated Hemoglobin

A new systematic review and meta-analysis published in BMC Endocrine Disorders has established that continuous glucose monitoring (CGM) is a superior alternative to traditional fingerstick monitoring for adults with type 2 diabetes (T2D) on insulin therapy. Analyzing data from 13 randomized controlled trials involving 1550 participants, investigators found that CGM use led to a statistically significant reduction in glycosylated hemoglobin (HbA_1C) by a mean difference of 2.78 mmol/mol compared to self-monitoring of blood glucose (SMBG). Crucially for patient safety, the study also demonstrated a meaningful decrease in the time patients spend in hypoglycemia, or time below range, with a mean difference reduction of 1.30%.¹

“CGM provides a dynamic profile of glucose fluctuations, enabling the evaluation of critical parameters such as HbA_1C, time in range (TIR), time below range (TBR), and time above range (TAR), metrics that are not captured by intermittent SMBG measurements,” the study authors said. “Recent studies suggest that CGM systems provide non-negligible advantages over SMBG, particularly in improving glycemic indices, reducing the risks of hypo- or hyper-glycemia, and potentially enabling proactive insulin adjustments.”

Although the primary analysis showed nonsignificant trends in time in range and time above range for the group as a whole, subgroup analyses revealed that real-time CGM (rtCGM) specifically provided significant improvements across all 4 glycemic indices, whereas intermittently scanned CGM did not reach the same level of statistical significance in these specific trials.

These findings suggest that the automatic data transmission and predictive alerts found in rtCGM may offer distinct advantages in enabling proactive insulin adjustments. However, the researchers noted substantial heterogeneity in the HbA_1C results, which they attributed to unmeasured factors like patient adherence, diabetes duration, or the specific generation of technology used.^1,2

For pharmacists, who are increasingly responsible for diabetes education and device management, these clinical gains are just one part of the narrative. Beyond the data, CGM serves as a transformative educational tool that helps patients visualize how diet, stress, and physical activity immediately impact their glucose levels. Modern systems are also expanding their utility through integration with smart connected insulin pens and automated insulin delivery systems. These technologies allow users to track dosages, calculate optimal units, and receive reminders, which have been shown to improve adherence and reduce long-term health care costs by preventing expensive complications like end-stage renal disease and retinopathy.²

Recognizing the expanding role of pharmacists in the primary care setting, recent educational research emphasizes the value of firsthand professional experience with these devices. A study involving pharmacy students who wore a CGM sensor for 1 week found that this practical immersion significantly increased their confidence in interpreting ambulatory glucose profile (AGP) reports and making therapeutic recommendations to the healthcare team. This experiential learning also fostered deeper empathy for patients, particularly regarding the daily burdens of alarm fatigue—such as being woken up by nighttime alerts—and the potential stigma associated with wearing a visible medical device.³

Despite the clear clinical benefits, pharmacists must also help patients navigate significant practical and physical barriers to adherence. Technical issues such as signal loss and skin-related complications remain common, with erythema and pruritus affecting a high percentage of users. Allergic contact dermatitis, often caused by adhesive components like isobornyl acrylate, can be severe enough to cause patients to discontinue use.

Furthermore, though CGM has proven cost-effective in the long term across multiple countries and health care systems, high upfront costs and limited insurance coverage still hinder widespread adoption. Successful implementation ultimately requires a multidisciplinary approach where structured education is prioritized to help patients set realistic expectations, manage alarms, and adjust their insulin regimens safely.

“The findings of this review will inform clinical decision-making by elucidating the optimal glucose monitoring strategy, thereby potentially mitigating the risk of diabetes-related complications in this patient population,” the study authors said.¹

READ MORE: Diabetes Resource Center

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REFERENCES

1. Zhu J, Zhang L. 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. BMC Endocr Disord. Published online April 6, 2026. doi:10.1186/s12902-026-02167-4

2. Kwon SY, Moon JS. Advances in Continuous Glucose Monitoring: Clinical Applications. Endocrinol Metab (Seoul). 2025;40(2):161-173. doi:10.3803/EnM.2025.2370

3. Gamal Eldin A, Nogid A. Integrating Continuous Glucose Monitoring Into Pharmacy Elective Curriculum: A Practical Learning Experience. J Pharm Technol. Published online October 17, 2025. doi:10.1177/87551225251379742