The incidence of contrast-induced nephropathy in trauma patients.

BACKGROUND: We measured the incidence and risk factors for contrast-induced nephropathy (CIN) in trauma patients.

METHODS: We conducted a retrospective review of a prospectively collected trauma database. We studied injured patients who received a contrast-enhanced computer tomography with an initial and repeat serum creatinine after 48 h. Exclusion criteria were patients on dialysis. CIN was defined as a 25% rise in creatinine or an increase in creatinine > or =0.5 mg/dl from baseline 48 h after contrast. Data were reported as means+/-SD. Group comparisons were made by Fisher's exact test or Student's t-test (alpha=0.05, two tails).

RESULTS: In total, 235 patients were studied with an average age of 44+/-20 (13-92 years) (80% men), 79% of whom had blunt injuries. CIN incidence was 5.1% [95% confidence interval (CI), 2.9-8.8%]. No patients in the CIN or non-CIN groups died, or required in-patient/chronic dialysis. CIN patients were significantly (P=0.003) older (61 vs. 43 years). For age > or =75 years, the relative risk was 7.7 and the number needed to harm was 5. An elevated creatinine (more than 1.5 mg/dl) was significantly (P=0.007) associated with CIN. For creatinine greater than 1.5 mg/dl, the relative risk was 6.4 and the number needed to harm was 6. CIN was significantly (P=0.02) more likely in patients with glomerular filtration rate less than 60 ml/min/1.73 m. We found no significant (P>0.05) difference in base-deficit, lactate, and Injury Severity Score between CIN and non-CIN patients.

CONCLUSION: We found a 5.1% incidence of CIN in trauma patients exposed to intravenous contrast. Elderly and trauma patients with low glomerular filtration rate were especially predisposed to CIN.