Continuous glucose monitoring during hospitalization: yes or no?

Abstract

The use of continuous glucose monitoring (CGM) in hospitalized patients is a topic of growing relevance, and current evidence leans favorably towards its adoption over intermittent point-of-care (POC) testing, albeit with important considerations.

The primary advantage of CGM is the significant improvement in glycemic control. A meta-analysis of randomized controlled trials demonstrated that CGM increases "time in range" (70–180 mg/dL) and, crucially, reduces time in hypoglycemia in non-critical patients. This latter point is fundamental to patient safety, as hypoglycemia is associated with increased morbidity and mortality. Beyond glycemic metrics, studies in high-risk populations, such as frail and critically ill patients with COVID-19, have associated CGM use with a drastic reduction in mortality and shorter stays in the Intensive Care Unit (ICU).  

However, the technology is not without limitations. The main one is that it measures glucose in the interstitial fluid, which implies a physiological lag compared to blood glucose. Its accuracy, quantified by the Mean Absolute Relative Difference (MARD), can be variable and is compromised in critically ill patients with hemodynamic instability (e.g., hypotension, shock) or by interfering substances. Therefore, CGM does not completely replace POC measurements, which remain necessary to confirm values before making critical therapeutic decisions.  

In conclusion, the answer is a conditional but resounding "yes." CGM is emerging as the new standard of care due to its demonstrated benefits in safety and efficacy. Its successful implementation depends on a hybrid approach (CGM + POC), with clear institutional protocols, integration into healthcare systems, and adequate staff training. For institutions willing to adopt this framework, CGM represents a fundamental tool for improving the quality of care for hospitalized patients with diabetes.