Protein Intake

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: * Group 1 (Standard Protein): ≤1.2 g/kg/day * Group 2 (High Protein): \>1.2 g/kg/day No additional interventions will be performed; data are collected from medical records. 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: * Primary Outcome: Time to recovery of kidney function within 30 days, measured by creatinine returning close to baseline values. * Secondary Outcomes: Changes in blood urea levels, duration of renal replacement therapy (hemodialysis), ICU length of stay, and 30-day mortality. 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.

When a patient has dialysis some nutrients are lost in the process. Nutritional losses include protein, trace elements (i.e. zinc, copper and selenium) and water-soluble vitamins (Vitamins C and B). These nutrients are essential for normal body function, including a good immune system and nutritional status. For example, on average the protein losses during a dialysis session (the process where the blood is cleaned via a machine and special fluid) is equal to 6g of protein/day (which is the equivalent of the amount of protein in 1 egg). Protein needs for the general population are 0.8g protein per kg of body weight. Because people on dialysis lose protein via the dialysis, it is thought that these people need to eat more protein. Currently, in clinical practice for people receiving dialysis, the guidelines are to aim for 1.1 -1.4g of protein per kg of body weight. However, the research is old and very weak. Dialysis treatments have changed over the past 40 years, and the investigator does not know if the replacement of these nutritional losses is important to how well people do on dialysis and if they have any effect on survival. Previous research is mostly limited to haemodialysis (a type of dialysis that requires a machine which cleans the patients' blood via special filters) and peritoneal dialysis (this is a type of dialysis which happens via the patients' tummy). There is no research on the nutritional supplementation in home HD and nocturnal HD. Our research will investigate if a higher protein provision leads to a reduction is hospital admissions and improved outcomes in patients receiving dialysis.