Urea-to-Creatinine Ratio as a Marker of Metabolic Transition in Septic Shock: A Comparison With Indirect Calorimetry

February 9, 2026 updated by: José Raimundo Araujo de Azevedo, Hospital Sao Domingos

Urea-to-Creatinine Ratio as a Marker of Metabolic Transition in Septic Shock: A Comparison with Indirect Calorimetry.

This study investigates whether the urea-to-creatinine ratio can serve as a simple marker of metabolic state in patients with septic shock. Septic shock is associated with hypermetabolism and severe protein catabolism, which worsen outcomes. Although indirect calorimetry is the gold standard for measuring energy expenditure and metabolic demand in critically ill patients, its availability in ICUs is limited.

The authors hypothesize that the urea-to-creatinine ratio reflects protein catabolism and correlates with energy expenditure measured by indirect calorimetry, making it a potential tool to identify the transition from the catabolic to the anabolic phase and to guide nutritional therapy. The primary objective is to assess the correlation between the urea-to-creatinine ratio and energy expenditure in septic shock patients. Secondary objectives include evaluating changes in systemic inflammation over time using C-reactive protein (CRP).

This is a prospective observational cohort study of adult patients with septic shock admitted to a medical-surgical ICU who require at least three days of mechanical ventilation and undergo indirect calorimetry. Energy expenditure will be measured at predefined intervals during the ICU stay, while urea, creatinine, and CRP levels will be collected regularly. Patients with severe renal dysfunction, renal replacement therapy, or high oxygen requirements will be excluded.

Data will be analyzed across three time periods during mechanical ventilation to examine trends in energy expenditure, urea-to-creatinine ratio, and inflammation. Demographic and clinical variables will also be collected. The study aims to determine whether changes in the urea-to-creatinine ratio mirror metabolic transitions detected by indirect calorimetry, potentially offering a practical alternative for metabolic monitoring in septic shock patients.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Urea-to-Creatinine Ratio as a Marker of Metabolic Transition in Septic Shock: A Comparison with Indirect Calorimetry

INTRODUCTION: Patients with septic shock develop profound metabolic alterations characterized by hypermetabolism and accelerated protein catabolism, leading to loss of lean body mass and worse clinical outcomes. Indirect calorimetry is the gold standard for assessing energy expenditure and metabolic demand in critically ill patients; however, it is not widely available in ICUs.

The urea-to-creatinine ratio has been proposed as a simple and readily available marker of protein catabolism. Nevertheless, its relationship with measured energy expenditure remains unclear.

HYPOTHESIS: The urea/creatinine ratio may be an efficient catabolism marker to guide nutritional therapy in critically ill patients. Evidence to confirm this hypothesis can be obtained by comparing the urea-to-creatinine ratio with indirect calorimetry, which is the gold standard for evaluating energy expenditure and metabolic demands in these patients.

OBJECTIVES: The primary objective of this study is to evaluate the correlation between the urea-to-creatinine ratio and energy expenditure measured by indirect calorimetry in patients with septic shock, in order to identify the transition from the catabolic to the anabolic phase. This transition is expected to be reflected by a reduction in the urea-to-creatinine ratio accompanied by a decrease in measured energy expenditure.

Secondary objectives include the analysis of inflammatory activity over time, as assessed by C-reactive protein (CRP) levels.

METHODS: This is a prospective observational cohort study including adult patients with septic shock, defined according to Sepsis-3 criteria, admitted to a 53-bed medical-surgical intensive care unit between April 2026 and March 2027. Eligible patients will be required to have undergone invasive mechanical ventilation for at least three consecutive days and to have had energy expenditure measured by indirect calorimetry.

Indirect calorimetry assessments will be performed on days 1, 4, 7, 11, 14, 17, and 20 after ICU admission. Patients will be excluded if they had a serum creatinine level greater than 4.0 mg/dL at hospital admission, chronic kidney disease requiring dialysis, initiation of renal replacement therapy during ICU stay, or if they require an inspired oxygen fraction (FiO₂) greater than 70% on the fourth day of mechanical ventilation.

Energy expenditure measurements will be obtained using the E-COVX module integrated into the Carescape B650 monitor (GE Healthcare, Helsinki, Finland). Urea and creatinine levels will be collected daily, and the urea-to-creatinine rati calculated accordingly. CRP levels will also be measured as an indicator of systemic inflammation.

For analysis, energy expenditure, urea-to-creatinine ratio, and CRP values will be grouped into three time periods based on days since initiation of mechanical ventilation: days 1-4, days 7-11, and days 14-20.

Demographic and clinical data to be collected include age, sex, Simplified Acute Physiology Score III (SAPS III), Sequential Organ Failure Assessment (SOFA) score at admission, admission category (medical or surgical), the sepsis focus and relevant comorbidities. Data will be collected prospectively using standardized case report forms.

Written informed consent will be obtained from patients or their legal representatives. The study protocol will be submitted for approval to the Research Ethics Committee of Hospital São Domingos

Study Type

Observational

Enrollment (Estimated)

40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: JOAMMA QUARIGUASI, MD
  • Phone Number: +55 98 98418-6565
  • Email: joamaq@gmail.com

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Adult patients with septic shock, defined according to Sepsis-3 criteria, admitted to a 53-bed medical-surgical intensive care unit between April 2026 and March 2027. Eligible patients will be required to have undergone invasive mechanical ventilation for at least three consecutive days and to have had energy expenditure measured by indirect calorimetry.

Description

Inclusion Criteria: Adult patients with septic shock, defined according to Sepsis-3 criteria, admitted to a 53-bed medical-surgical intensive care unit between April 2026 and March 2027. Eligible patients will be required to have undergone invasive mechanical ventilation for at least three consecutive days -

Exclusion Criteria:Patients will be excluded if they had a serum creatinine level greater than 4.0 mg/dL at hospital admission, chronic kidney disease requiring dialysis, initiation of renal replacement therapy during ICU stay, or if they require an inspired oxygen fraction (FiO₂) greater than 70% on the fourth day of mechanical ventilation.

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Septic shock patients
Patients will be submmited to determinations os indirect calorimetry and urea-to-creatinine ratio on days 1, 4, 7, 11, 14, 17 and 20

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Urea-to-creatinine ratio and energy expenditure measured by indirect calorimetry
Time Frame: 20 days
To evaluate the correlation between the urea-to-creatinine ratio and energy expenditure measured by indirect calorimetry in patients with septic shock, in order to identify the transition from the catabolic to the anabolic phase. Urea and creatinine will be determined on days 1,4,7,11, 14,17 and 20. In the same period patients will be submmited to determination of energy expenditure by indirect calorimetry using the E-COVX module integrated into the Carescape B650 monitor (GE Healthcare, Helsinki, Finland).
20 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
C-reactive protein (CRP)
Time Frame: 20 days
Analysis of inflammatory activity over time, as assessed by C-reactive protein (CRP) levels.
20 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospital Sao Domingos

Investigators

  • Principal Investigator: JOSE AZEVEDO, MD, PhD, Hospital São Domingos

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

October 1, 2027

Study Registration Dates

First Submitted

February 9, 2026

First Submitted That Met QC Criteria

February 9, 2026

First Posted (Actual)

February 17, 2026

Study Record Updates

Last Update Posted (Actual)

February 17, 2026

Last Update Submitted That Met QC Criteria

February 9, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Study 01-2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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