Proteinuria as a predictor of renal dysfunction in trauma patients receiving intravenous contrast

Trauma patients have unknown comorbidities, multiple injuries, and incomplete laboratory testing, yet require contrast-enhanced imaging to identify potentially life-threatening problems. Our goal was to characterize contrast-induced nephropathy (CIN) in this population. We retrospectively reviewed characteristics of 402 patients who presented to a Level II trauma center and received contrast-enhanced imaging. CIN was defined as creatinine rise of 0.5 mg/dL or greater or 25 per cent or greater from baseline within 48 hours. CIN occurred in 7.7 per cent and four patients required hemodialysis. Patients with CIN were older, had lower admission hemoglobin, higher Injury Severity Score, and received more blood products. Factors that predicted CIN included: male sex, age older than 46 years, body mass index less than 27 kg/m², glomerular filtration rate less than 109 mL/min/1.73 m ², hemoglobin less than 12 mg/dL, hematocrit less than 36 per cent, proteinuria, 2 units or more of fresh-frozen plasma in 48 hours, and alcohol use. Odds ratio for developing CIN with two, five, or six of these factors was 3.39, 6.54, and 8.38, respectively. A match-controlled analysis for Injury Severity Score and age in patients with CIN versus non-CIN patients revealed the strongest predictor of CIN was proteinuria (relative risk, 2.5; confidence interval, 1.1 to 5.8). Although it is difficult to truly differentiate CIN from renal dysfunction related to injury severity in trauma patients, proteinuria may be an important factor in identifying nephropathy in this population.