An observational study in Acute Kidney Failure, Critical Illness and Protein Intake, sponsored by Hospital Italiano de Buenos Aires. Recruiting at 6 sites in Argentina. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-05.
Sponsored by Hospital Italiano de Buenos Aires · Observational
Background:
Acute kidney injury (AKI) is common in critically ill patients and is associated with worse outcomes, including longer ICU stay, need for dialysis, and higher mortality. Patients with AKI often experience significant protein and calorie loss due to their illness and medical treatments. Providing the right amount of protein may help maintain muscle mass and improve recovery; however, consuming too much protein could potentially worsen kidney function. Current international guidelines recommend adequate protein intake, but the best dose remains uncertain, especially for patients with AKI.
Study Purpose:
This research will examine whether patients with AKI who receive a higher protein intake (greater than 1.2 g/kg/day) have different outcomes compared to those who receive a standard or lower protein intake (≤1.2 g/kg/day). The primary outcome is whether a higher protein intake leads to a longer recovery time from AKI or worsens kidney function.
Study Design:
This is a retrospective, multicenter study using data from five hospitals in Argentina. It is designed as a "target trial emulation," meaning researchers will analyze existing patient data as if it were a randomized clinical trial. Patients will be included on the fifth day of their ICU stay and classified into two groups based on their protein intake on day 5:
Study Population:
The study will include adult patients (≥18 years) admitted to the ICU who are receiving exclusive enteral or parenteral nutrition and have AKI (or worsening chronic kidney disease) according to KDIGO criteria. Patients with advanced chronic kidney disease (creatinine clearance \<30 ml/min/1.73 m²) or undergoing hemodialysis at T0, previous kidney transplant, severe liver disease, or BMI >30 will be excluded.
Outcomes:
Statistical Approach:
To minimize bias, the study will use advanced statistical methods, including propensity score weighting, to ensure fair comparison between groups. Competing risks (such as death before kidney recovery) will be taken into account in the analysis.
Significance:
This study will provide important information about the safety and effectiveness of higher protein intake in critically ill patients with AKI. The findings may help guide nutritional strategies in the ICU, optimize kidney outcomes, and improve patient care.
Background:
Acute kidney injury (AKI) is a frequent complication in critically ill patients and is associated with prolonged hospital stay, need for renal replacement therapy (RRT), and higher mortality. Patients with AKI often develop protein-calorie malnutrition due to increased catabolism, inflammation, and nutrient losses. This is further aggravated when RRT is required, as dialysis contributes to nitrogen and amino acid losses. Clinical guidelines recommend providing an adequate protein intake to support recovery; however, the optimal protein dose remains uncertain.
Recent trials, such as the EFFORT Protein study, suggest that higher protein intake may benefit some critically ill patients, especially those with malnutrition or frailty. However, the same study also indicated potential harm in patients with severe illness or AKI, showing that excessive protein intake (>2.2 g/kg/day) could worsen kidney outcomes and increase mortality.
Given the uncertainty regarding the actual effect of increased protein intake in patients with AKI-and the possibility that it may be harmful in those with persistent AKI-this study uses a Target Trial Emulation approach to evaluate whether protein intake on the fifth day of ICU admission exceeding 1.2 g/kg/day leads to prolonged duration of AKI in critically ill patients.
Objective:
This study aims to evaluate whether a higher protein intake (>1.2 g/kg/day) compared with standard or lower intake (≤1.2 g/kg/day) affects the duration of AKI and clinical outcomes in critically ill patients.
Study Design:
This is a retrospective, multicenter study using a target trial emulation design. Patient data will be collected from electronic health records of five tertiary hospitals in Argentina. Eligible patients will be identified on the fifth day of their ICU admission, referred to as Time Zero (T0). Classification into treatment groups will depend on protein intake at T0:
Population:
Inclusion criteria: age ≥18 years, ICU admission, exclusive enteral or parenteral nutrition, and presence of AKI or worsening chronic kidney disease as defined by KDIGO criteria (rise in serum creatinine >0.3 mg/dL within 48 hours, or 1.5-fold increase within 7 days).
Exclusion criteria: advanced chronic kidney disease (creatinine clearance \<30 ml/min/1.73 m²) or dialysis at admission, prior kidney transplant, severe liver disease (Child-Pugh >7), AKI requiring RRT at baseline (T0), or body mass index >30.
Primary Outcome: Time to recovery of kidney function within 30 days, defined as return of serum creatinine to ≤1.5 times baseline or ≤30% above baseline, with death considered as a competing event.
Secondary Outcomes:
Sample Size: Based on prior literature, we estimated that 172 patients per group are required for non-inferiority testing with 80% power, α = 0.05, and a non-inferiority margin of 2 days of AKI. Adjustments for potential confounders indicate that at least 105 patients per group will be necessary.
Statistical Analysis:
Ethical Considerations:
This study involves a retrospective review of de-identified patient data. It poses minimal risk, as no interventions are introduced beyond standard care. Confidentiality will be strictly maintained in accordance with national and local regulations, including Argentina's Personal Data Protection Law (Law 25,326). Informed consent will be waived in accordance with CIOMS guidelines, as the study is retrospective, presents minimal risk, and has significant social and scientific value.
Significance:
This study will provide new evidence on the safety and effectiveness of protein dosing in critically ill patients with AKI. The results may inform future guidelines on nutritional therapy in the ICU and optimize outcomes for patients at high risk of kidney complications.
1,691 studies on the registry are indexed under Acute Kidney Injury; 395 are open to participants now.
This study's planned enrollment of 344 is above the median of 160 across 814 observational studies indexed under Acute Kidney Injury.
Browse Acute Kidney Injury studies →Hospital Italiano de Buenos Aires is the lead sponsor of 133 studies on the registry; 24 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The study population consists of critically ill adult patients (≥18 years) admitted to intensive care units at five tertiary hospitals in Argentina. Eligible patients are those receiving exclusive enteral or parenteral nutrition who present with acute kidney injury (AKI) or worsening chronic kidney disease according to KDIGO criteria. Patients with advanced chronic kidney disease (creatinine clearance \<30 ml/min/1.73 m²) or hemodialysis at admission, previous kidney transplant, severe liver disease, or body mass index (BMI) >30 are excluded.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients in this group will be those whose documented protein intake on ICU day 5 is ≤1.2 g/kg/day. No additional interventions are administered as part of the study; classification is based solely on protein intake recorded in the medical record.
Patients in this group will be those whose documented protein intake on ICU day 5 is greater than 1.2 g/kg/day. No additional interventions are administered as part of the study; classification is based solely on protein intake recorded in the medical record.
Time to recovery of kidney function
Recovery of kidney function will be defined as the serum creatinine returning to ≤1.5 times the baseline value or ≤30% above the baseline value, with death considered a competing event. The analysis will compare patients receiving ≤1.2 g/kg/day vs. \>1.2 g/kg/day of protein intake on ICU day 5.
Time frame: Within 30 days from ICU day 5 (Time Zero) or until ICU discharge, whichever occurs first.
Change in blood urea levels at day 14
Comparison of serum urea concentration between groups at day 14 after ICU day 5 (Time Zero). The outcome will assess whether patients with higher protein intake (\>1.2 g/kg/day) show different urea values compared with those with standard intake (≤1.2 g/kg/day).
Time frame: 14 days from ICU stay (T0)
ICU length of stay
Comparison of the duration of ICU stay between groups classified by protein intake on day 5 of ICU stay. Discharge will be considered the endpoint, with death treated as a competing event in the analysis.
Time frame: Within 30 days from ICU day 5 (Time Zero) or until ICU discharge, whichever occurs first.
Mortality at 30 days
Proportion of patients who die within 30 days. The outcome will compare mortality rates between patients with higher protein intake (\>1.2 g/kg/day) and those with standard intake (≤1.2 g/kg/day).
Time frame: Within 30 days or until hospital discharge, whichever occurs first.
Plan to share: Undecided — The study team is currently evaluating the feasibility of sharing de-identified individual participant data, taking into account ethical approvals, data privacy regulations, and the resources required for proper anonymization and curation. A final plan will be determined after completion of data collection and primary analyses.
Started Sep 2025 (actual). Primary completion is estimated for Aug 2026, 11 months after the start.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Hospital Italiano de Buenos Aires →