Repeated Contrast Exposure and Kidney Outcomes in Critically Ill Patients With Pre-Existing Renal Dysfunction: A Prospective Cohort Study

Methodology

Study design, recruitment and study location: This is a prospective observational cohort study. Patients were consecutively recruited from the intensive care units of Cairo University hospitals between March 2024 and November 2025 and were followed after discharge through outpatient clinics, in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. The study protocol approved by the Faculty of Medicine, Cairo University Research Ethics Committee, on 13-1-2024, with the approval number N-20-2024.

Exposure groups: Participants were categorized into two groups according to the number of intravascular contrast administrations received during the study period into two groups.

• Group I: patients who underwent a single contrast exposure with impaired kidney function.
• Group II: Patients who received two contrast administrations with impaired kidney function.

Data collection: For the enrolled patients, baseline variables were extracted from the hospital database. Before any data handling or analysis, all records were comprehensively anonymized to ensure confidentiality. Collected data included demographic characteristics (age, sex, and body mass index), clinical parameters (blood pressure, primary diagnosis, cause of ICU admission, CKD stage, smoking status), comorbid conditions (diabetes mellitus, hypertension, heart failure/cardiovascular disease, liver disease, previous stroke and dyslipidemia) and medication history (angiotensin converting enzyme inhibitors/angiotensin receptor blockers, sodium-glucose cotransporter 2 inhibitors, and statins).