CONTINUOUS GLUCOSE MONITORING (CGM): EVOLUTION OF SENSORS AND THE USE OF METRICS BEYOND GLYCATED HEMOGLOBIN, SUCH AS "TIME IN TARGET"
DOI:
https://doi.org/10.56238/arev8n4-056Keywords:
Continuous Glucose Monitoring, Time to Target, Glycemic Variability, Glycated Hemoglobin, Type 1 Diabetes MellitusAbstract
Introduction: Intensive management of type 1 diabetes mellitus (T1DM) has historically been based on glycated hemoglobin (HbA1c) and capillary blood glucose self-monitoring (CBSM), methods that have limitations in not adequately reflecting glycemic variability, trends, and the risk of hypoglycemia. Recently, technological advances in Continuous Glucose Monitoring (CGM) have enabled the use of more dynamic and precise metrics, notably Time to Target (TRT). Objective: To synthesize the technological and clinical evolution of CGM systems, evaluating how the adoption of metrics beyond HbA1c, with emphasis on TRT, redefines therapeutic goals and impacts the safety and quality of life of patients with T1DM. Methodology: A narrative literature review of a qualitative and descriptive nature was conducted. The search was conducted in the electronic databases PubMed, Web of Science, Scopus, and Cochrane Central, prioritizing publications between 2006 and 2026 that evaluated primary glycemic outcomes with the use of diabetes technologies. Results: Evidence shows that the use of CGM is associated with a reduction in HbA1c, less exposure to hypoglycemia, and an increase in IRR when compared to SMBG. In the comparison between devices, real-time CGM (rtCGM) demonstrated superiority over intermittent scanning systems (isCGM) in relation to IRR and safety against hypoglycemia, due to its ability to generate predictive alerts and operate in a closed loop. The literature confirms that the correlation between HbA1c and IRR is only partial; apparently adequate HbA1c values can coexist with severe glycemic instability. Furthermore, IRR proved to be the metric most consistently associated with a reduction in chronic complications (such as retinopathy and albuminuria) and mortality. From an engineering standpoint, interstitial fluid biosensors remain the clinically validated gold standard, as non-invasive technologies still face challenges in accuracy and consolidation. Conclusion: Diabetes monitoring has undergone a paradigm shift, correcting the "average fallacy" imposed by HbA1c. Although HbA1c maintains historical relevance, contemporary control requires complementary assessment of Time to Target (TTR), Time Below Range (TBR), and glycemic variability to ensure therapeutic efficacy, individualize clinical risk, and safely improve long-term outcomes in diabetes.
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