Clinical Trial Protocol for Continuous Glucose Monitoring in Critical Care (CGM-UCI23)

Continuous Glucose Monitoring in Critically Ill Patients: a Randomized Controlled Trial in the Intensive Care Units of Hospital Clínic of Barcelona (CGM-UCI23)

High blood glucose levels (hyperglycaemia) are very common in patients admitted to intensive care units (ICUs) and are associated with worse health outcomes. Traditionally, glucose levels in critically ill patients are monitored using point-of-care blood glucose (POC-G) testing (fingerstick, arterial, or venous blood samples), which may require multiple measurements each day.

Continuous glucose monitoring (CGM) is a technology that measures glucose levels continuously throughout the day and night, providing real-time information and alerts when glucose levels are too high or too low. Previous studies have shown that CGM can be used safely in critically ill patients and may reduce the number of blood glucose tests required. However, more evidence is needed to determine whether CGM improves glucose control and patient outcomes in the ICU.

The purpose of this study is to compare CGM-based glucose management with standard point-of-care glucose testing in critically ill patients with hyperglycaemia admitted to the Hospital Clínic of Barcelona. Participants will be randomly assigned to one of two groups. In the experimental group, healthcare professionals will use real-time CGM data to make glucose management decisions. In the control group, glucose management will be based on standard point-of-care testing, while CGM data will be collected in the background for later analysis.

The study will evaluate whether CGM improves the amount of time that glucose levels remain within the target range, reduces episodes of high and low glucose, decreases the number of blood glucose tests required, and influences patient outcomes such as complications, hospital readmissions, and mortality up to 90 days after ICU discharge.

Researchers hope that the results of this study will help determine whether CGM should become part of routine ICU care, improving patient safety, reducing the burden of glucose monitoring, and supporting more efficient clinical decision-making.

Study Overview

• Status: Completed
• Conditions: Critical Illness; Hyperglycaemia; Continuous Glucose Monitoring; Critical Care, Intensive Care; Glucose Control; Critical Care Nursing
• Intervention / Treatment: Device: Conventional Glucose Measurement; Device: Continuous Glucose Monitoring

• Study Type: Interventional
• Enrollment (Actual): 400
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Catalonia
    • Barcelona, Catalonia, Spain, 08036
      • Carrer de Villarroel, 170

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Aged 18 years or over
• Stay in ICU and/or intermediate care
• Blood glucose levels >180 mg/dL (10 mmol/L).

Exclusion Criteria:

• Pregnancy
• Contraindications for the use of CGM (such as skin issues or allergies to adhesives)
• End-of-life process

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: Conventional Glucose Measurement; Participants receive standard glycemic management according to ICU standard practice. Capillary blood glucose is the primary method used for insulin dose adjustment and is complemented, when clinically indicated, by arterial or venous blood glucose measurements. On average, approximately six blood glucose measurements are performed per day; however, the frequency may be increased or decreased according to the prescribed treatment regimen, insulin requirements, and the patient's clinical condition during ICU admission. CGM is used throughout the study period to collect glucose data. In this control arm, CGM data are blinded to healthcare professionals and are not used for clinical decision-making, serving as a sham intervention for study comparison purposes. All therapeutic decisions, including insulin dose adjustments, are based exclusively on conventional blood glucose measurements according to standard ICU practice.	Device: Conventional Glucose Measurement; Conventional glucose monitoring consists of capillary blood glucose measurements as the primary method for insulin dose adjustment according to standard ICU practice, complemented by arterial or venous blood glucose measurements when clinically indicated, all know as POC-G measurements. Glucose is typically measured approximately six times daily, with frequency adjusted according to clinical condition and insulin requirements. During the study, a CGM device is worn only for glucose data collection; CGM values remain blinded to healthcare professionals and are not used for clinical decision-making. All therapeutic decisions are based exclusively on conventional blood glucose measurements.; Other Names: Sham Group; POC-G Group; Conventional Group
Experimental: Continuous Glucose Monitoring Group; Participants randomized to the experimental group will receive glucose management guided by a CGM system. A CGM sensor will be inserted on the upper arm or abdomen and will provide real-time glucose measurements every 5 minutes. Glucose values, trends, and alerts for hyperglycaemia and hypoglycaemia will be available to the clinical team and used to support glycaemic management decisions during the ICU stay. The CGM system will be configured with predefined glucose alerts and predictive hypoglycaemia alarms. Healthcare professionals may perform additional point-of-care glucose measurements when clinically indicated, including confirmation of hypoglycaemia, extreme glucose values, or during intravenous insulin therapy according to safety criteria.	Device: Continuous Glucose Monitoring; CGM uses a subcutaneous sensor inserted into the upper arm or abdomen to measure interstitial glucose every 5 minutes. The system provides real-time glucose values, trends, and configurable alerts for hyperglycaemia and hypoglycaemia to support glycaemic management. Point-of-care blood glucose measurements may be performed when clinically indicated for confirmation of hypoglycaemia, extreme glucose values, or according to institutional safety protocols during intravenous insulin therapy.; Other Names: CGM; CGM Guided

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time in Range	Percentage of time that glucose values remain within the target range of 70-180 mg/dL (3.9-10.0 mmol/L), measured by continuous glucose monitoring.	During ICU stay (up to 10 days or until ICU discharge, death, or sensor removal).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time Above Range (TAR)	Percentage of time that glucose values are above 180 mg/dL (10.0 mmol/L), measured by continuous glucose monitoring.	During ICU stay (up to 10 days or until ICU discharge, death, or sensor removal).
Time Below Range (TBR)	Percentage of time that glucose values are below 70 mg/dL (3.9 mmol/L), measured by continuous glucose monitoring.	During ICU stay (up to 10 days or until ICU discharge, death, or sensor removal).
Number of Point-of-Care Glucose Measurements	Total number of point-of-care glucose measurements performed during ICU admission.	During ICU stay (up ICU discharge or death)
Hospital Readmissions	Number of participants readmitted to the hospital following discharge from the ICU.	Up to 90 days after ICU discharge.
Morbidity at 90 Days	Presence of illness, disease, or complications affecting health status, quality of life, or functional ability that occur during hospitalization or within 90 days following ICU discharge.	Up to 90 days after ICU discharge.
Mean Absolute Relative Difference (MARD)	Accuracy of continuous glucose monitoring assessed by the Mean Absolute Relative Difference (MARD) between continuous glucose monitoring values and paired point-of-care glucose measurements. MARD will be calculated as the mean of the absolute relative differences between paired glucose values and expressed as a percentage.	During ICU stay (up to 10 days or until ICU discharge, death, or sensor removal).
Diabetes Technology Society (DTS) Error Grid Analysis	Clinical risk associated with continuous glucose monitoring accuracy assessed using the Diabetes Technology Society (DTS) Error Grid. Paired continuous glucose monitoring and point-of-care glucose values will be classified according to risk categories, and the proportion of values within the no-risk and slight-risk zones will be reported.	During ICU stay (up to 10 days or until ICU discharge, death, or sensor removal).

Collaborators and Investigators

• Sponsor: Institut d'Investigacions Biomèdiques August Pi i Sunyer
• Investigators: Study Director: Eva M Guix-Comellas, PhD, University of Barcelona; Study Director: Alberto Villamor-Ordozgoiti, PhD, Hospital Clinic of Barcelona

Publications and helpful links

General Publications

• Agarwal S, Mathew J, Davis GM, Shephardson A, Levine A, Louard R, Urrutia A, Perez-Guzman C, Umpierrez GE, Peng L, Pasquel FJ. Continuous Glucose Monitoring in the Intensive Care Unit During the COVID-19 Pandemic. Diabetes Care. 2021 Mar;44(3):847-849. doi: 10.2337/dc20-2219. Epub 2020 Dec 23.
• Faulds ER, Boutsicaris A, Sumner L, Jones L, McNett M, Smetana KS, May CC, Buschur E, Exline MC, Ringel MD, Dungan K. Use of Continuous Glucose Monitor in Critically Ill COVID-19 Patients Requiring Insulin Infusion: An Observational Study. J Clin Endocrinol Metab. 2021 Sep 27;106(10):e4007-e4016. doi: 10.1210/clinem/dgab409.
• Panero-Moreno M, Muxella-Roson M, Dube-Llobet G, Cabrerizo-Jimenez M, Guix-Comellas EM, Villamor-Ordozgoiti A, Marsa-Perez N. The use of continuous glucose monitoring: A scoping review of accuracy, feasibility and nursing workload reduction in intensive care setting. Enferm Intensiva (Engl Ed). 2025 Jul-Sep;36(3):500534. doi: 10.1016/j.enfie.2025.500534.
• Rijkenberg S, van Steen SC, DeVries JH, van der Voort PHJ. Accuracy and reliability of a subcutaneous continuous glucose monitoring device in critically ill patients. J Clin Monit Comput. 2018 Oct;32(5):953-964. doi: 10.1007/s10877-017-0086-z. Epub 2017 Dec 7.
• Ammar MA, Ammar AA, Wee T, Deshpande R, Band M, Akhtar S. Relationship Between Glucose Time in Range in Diabetic and Non-Diabetic Patients and Mortality in Critically Ill Patients. J Intensive Care Med. 2022 Dec;37(12):1625-1633. doi: 10.1177/08850666221098383. Epub 2022 May 2.
• American Diabetes Association Professional Practice Committee for Diabetes*. 9. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes-2026. Diabetes Care. 2026 Jan 1;49(Suppl 1):S183-S215. doi: 10.2337/dc26-S009.
• Panero-Moreno M, Carbonell-Sabate C, Conesa-Gonzalez R, Risco-Patino L, Guix-Comellas EM, Villamor-Ordozgoiti A, Cordon-Arnau T. Continuous glucose monitoring in a critically ill patient with extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump, and continuous renal replacement therapy: Case report. Enferm Intensiva (Engl Ed). 2026 Apr-Jun;37(2):500589. doi: 10.1016/j.enfie.2026.500589. Epub 2026 Apr 11.
• Panero-Moreno M, Guix-Comellas EM, Villamor-Ordozgoiti A. Clinical trial protocol for continuous glucose monitoring in critical care at Hospital Clinic of Barcelona (CGM-UCI23). Nurs Crit Care. 2025 May;30(3):e13198. doi: 10.1111/nicc.13198. Epub 2024 Oct 28.

Study record dates

Study Major Dates

• Study Start (Actual): June 14, 2025
• Primary Completion (Actual): June 1, 2026
• Study Completion (Actual): June 1, 2026

Study Registration Dates

• First Submitted: June 2, 2026
• First Submitted That Met QC Criteria: July 4, 2026
• First Posted (Actual): July 7, 2026

Study Record Updates

• Last Update Posted (Actual): July 7, 2026
• Last Update Submitted That Met QC Criteria: July 4, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Metabolic Diseases; Glucose Metabolism Disorders; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Critical Illness; Hyperglycemia; Investigative Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Blood Chemical Analysis; Clinical Chemistry Tests; Diagnostic Techniques, Endocrine; Monitoring, Physiologic; Continuous Glucose Monitoring
• Other Study ID Numbers: HCB/2023/0377; PR678/2024 (Other Grant/Funding Number: Official College of Nurses of Barcelona); HOS-2023-021 (Other Grant/Funding Number: Dexcom); IRB00003099/CER052429 (Other Identifier: Bioethics Committee of the University of Barcelona)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: IPD that underlie the results reported in publications, after anonymization, will be available to qualified researchers upon reasonable request. Data sharing will require approval from the principal investigator and the relevant ethics committee and will comply with applicable data protection regulations.
• IPD Sharing Time Frame: Beginning 12 months after publication of the study results and ending 5 years after publication.
• IPD Sharing Access Criteria: Anonymized IPD underlying the published results to researchers upon reasonable request. Requests will be reviewed by the principal investigator and may require approval from the relevant ethics committee and the sponsoring institution. Data will be provided for scientifically sound research purposes and in accordance with applicable data protection regulations. Access will be granted through a secure data-sharing process following the execution of an appropriate data access agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No