This study aims to evaluate the incidence of acute kidney injury (AKI) among patients presenting with acute upper gastrointestinal bleeding (UGIB) at Sohag University Hospitals, and to identify predictors associated with renal impairment in these patients.

Upper gastrointestinal bleeding (UGIB) is a common medical emergency associated with significant morbidity and mortality. Acute kidney injury (AKI) is frequently observed in these patients, mainly due to hypovolemia and renal hypoperfusion. Despite its clinical importance, data regarding AKI incidence and predictors in UGIB patients, particularly in Middle Eastern populations, remain limited.

This prospective observational study aims to assess renal function abnormalities and identify predictors of AKI in patients with UGIB, including both variceal and non-variceal causes. The study will also evaluate clinical outcomes such as mortality, hospital stay duration, and need for renal replacement therapy.

Inclusion Criteria:

• Adult patients aged 18 years or older
• Patients presenting with clinical features suggestive of acute upper gastrointestinal bleeding (UGIB), including hematemesis, coffee-ground vomiting, or melena
• Diagnosis of UGIB confirmed by upper gastrointestinal endoscopy or strong clinical evidence when endoscopy is not immediately available
• Patients admitted to Sohag University Hospitals (medical wards or intensive care unit)
• Availability of renal function data, including at least one serum creatinine measurement at admission and serial measurements during hospitalization
• Availability of baseline renal function (previous serum creatinine within 3-12 months) or estimable baseline during hospitalization

Exclusion Criteria:

• Patients with end-stage renal disease (ESRD) on chronic dialysis
• Patients with a history of renal transplantation
• Patients with advanced chronic kidney disease stage 5 (eGFR <15 mL/min/1.73 m²) not on dialysis
• Patients with lower gastrointestinal bleeding
• Patients with incomplete or missing essential renal function data
• Patients discharged or deceased within 24 hours of hospital admission
• Pregnant patients
• Patients with acute kidney injury at presentation due to causes other than UGIB

Adult patients presenting with acute upper gastrointestinal bleeding and admitted to Sohag University Hospitals, including both ward and ICU patients, who meet the eligibility criteria and have available renal function data.

A decision regarding sharing individual participant data (IPD) has not yet been finalized. Any future data sharing will be considered in accordance with institutional policies and participant consent.