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NCT Number: NCT07624721

The Relationship Between Measured Creatinine Clearance and Acute Kidney Injury in Critically Ill Patients

With this study, the investigators want to find out how well different stages of acute kidney injury (AKI), match with the actual filtering ability of the kidneys in very sick adults in the intensive care unit (ICU). Kidney function will be measured using a urine test that estimates how much waste the kidneys can clear from the blood.

The investigators will also compare two ways of diagnosing and staging AKI: one based on how much urine a person makes, and the other based on blood creatinine levels (a waste product that rises when kidney function worsens). In addition, the investigators will examine how factors that can be changed (such as treatments or medications) and factors that cannot be changed (such as age or existing health conditions) may affect this relationship.

Finally, the investigators will look at whether drops in kidney function are linked to problems like high potassium levels in the blood and a buildup of acid in the body.

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Key information

Conditions

AKI - Acute Kidney Injury Acute Kidney Injury Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Kidney Diseases Male Urogenital Diseases Renal Insufficiency Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Ghent university hospital

Ghent, 9000, Belgium

About this study

The aim of this study is to investigate the relationship between the different stages of the KDIGO Acute Kidney Injury (AKI) criteria with measured creatinine Clearance using short-term creatinine clearance (Ccr) in critically ill adults admitted to the ICU. The investigators will also examine the difference between CCr and estimated Glomerular Filtration Rate (eGFR) and potential differences on this relationship when the urine output criteria are used versus when Scr is used for the diagnosis of the different AKI KDIGO stages. Additionally, the study will explore how modifiable and non-modifiable risk factors influence this relationship. Finally, we will evaluate how declines in GFR are associated with complications such as hyperkalemia and metabolic acidosis.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Admission ICU of Ghent university hospital
  • Availability of at least one serum creatinine clearance

Exclusion criteria

  • chronic RRT before ICU admission
  • RRT during ICU
  • Missing or incomplete data preventing KDIGO AKI classification

Treatment and study plan

Primary outcomes

  1. The association between KDIGO AKI stage and measured creatinine clearance.

    Time frame: from ICU admission until ICU discharge (average 4 days)

    During each patient's entire ICU stay, the KDIGO stage will be determined at every time point for which a measured creatinine clearance value is available. As this is a retrospective analysis, the timing and frequency of measured creatinine clearance assessments will vary between patients throughout their ICU stay.

    Measured creatine clearance will be corrected for body surface area and expressed as mL/min/1.73 m². The KDIGO classification categorizes AKI severity from mild to severe using a scoring system ranging from stage 1 to stage 3.

Secondary outcomes

  1. The association between KDIGO AKI 'urine output criteria' and 'serum creatinine criteria' and the measured creatinine clearance.

    Time frame: from ICU admission until ICU discharge (average 4 days)

    During each patient's entire ICU stay, the KDIGO stage will be determined at every time point for which a measured creatinine clearance value is available. As this is a retrospective analysis, the timing and frequency of measured creatinine clearance assessments will vary between patients throughout their ICU stay. Differences according to the KDIGO severity classification and its subcriteria 'serum creatinine changes' or 'urine output changes' will be evaluated. Measured creatinine clearance will be corrected for body surface area and expressed in mL/min/1.73 m².

  2. The association of gender with differences in measured creatinine clearance according to AKI severity.

    Time frame: from ICU admission until ICU discharge (average 4 days)

    The association of gender on measured creatinine clearance within different stages of AKI (based on KDIGO classification).

    During each patient's entire ICU stay, the KDIGO stage will be determined at every time point for which a measured creatinine clearance value is available. As this is a retrospective analysis, the timing and frequency of measured creatinine clearance assessments will vary between patients throughout their ICU stay. The gender of the patient is collected at ICU admission. Measured creatinine clearance will be corrected for body surface area and expressed in mL/min/1.73 m².

  3. Comparison of measured creatinine clearance in patients with chronic kidney disease (CKD) in the different AKI (KDIGO) stages

    Time frame: from ICU admission until ICU discharge (average 4 days)

    Comparison of measured creatinine clearance in patients with chronic kidney disease (CKD) versus those with normal baseline kidney function. Measured creatinine clearance will be compared in the different AKI KDIGO stages.

    During each patient's entire ICU stay, the KDIGO stage will be determined at every time point for which a measured creatinine clearance value is available. As this is a retrospective analysis, the timing and frequency of measured creatinine clearance assessments will vary between patients throughout their ICU stay. The stage of chronic kindey disease at ICU admission will be collected .

  4. Association of measured creatinine clearance and KDIGO stage with complications

    Time frame: from ICU admission until ICU discharge (average 4 days)

    Association of measured creatinine clearance and KDIGO stage with complications, including: Hyperkalemia, Acidemia, Need for renal replacement therapy. Data about complications will be collected during the entire ICU stay of the patient.

  5. The association between measured creatinine clearance and estimated glomerular filtration rate (eGFR)

    Time frame: from ICU admission until ICU discharge (average 4 days)

    Estimated glomerular filtration rate (eGFR) is generally used to assess renal function in stable patients. In this study, eGFR will be evaluated in critically ill ICU patients and compared with measured creatinine clearance.

    During each patient's entire ICU stay, the eGFR will be determined at every time point for which a measured creatinine clearance value is available. As this is a retrospective analysis, the timing and frequency of measured creatinine clearance assessments will vary between patients throughout their ICU stay.

    Measured creatinine clearance will be corrected for body surface area and expressed in mL/min/1.73 m². eGFR is expressed in the same unit, mL/min/1.73 m².

Sponsors and collaborators

Lead sponsor

University Hospital, Ghent

Other

Registry information

Official study title

Evaluating the Relationship Between Measured Creatinine Clearace and KDIGO AKI Criteria in Critically Ill Patients - A Retrospective Single-Center Study

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 3, 2026
Registry last updated
Jun 3, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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