Risk factors for acute kidney injury in the elderly undergoing contrast-enhanced computed tomography in the emergency department

Background: There have been few studies focusing on the incidence and risk factors for elderly patients undergoing computed tomography (CT) scans with intravascular contrast medium, who develop contrast-induced nephropathy (CIN) in the emergency department (ED). Our objective was to investigate the incidence of and risk factors for, CIN in elderly patients seen in the ED, who receive intravenous contrast media for CT examination. Methods: Patients ≥65 years of age who received contrast-enhanced CT were eligible for inclusion in this retrospective analysis. CIN was defined as an increase in serum creatinine (sCr) ≥0.5 mg/dL 48 to 72 hours after intravenous contrast administration. Multiple logistic regression analysis for risk factors for CIN and Chi-square test were performed for trend analysis for CIN incidence and mortality of different risk scores. Results: A total of 594 patients, with a mean age of 79.8 ± 6.8 years were included. The overall incidence of CIN was 8.6%. In multivariate analyses, CIN was associated with diabetes mellitus [adjusted odds ratio (OR) = 1.93; 95% confidence interval (CI) = 1.04-3.62], precontrast sCr >1.5 mg/dL (OR = 2.72; 95% CI = 1.44-5.13), and acute hypotension (OR = 3.56; 95% CI = 1.29-9.84). CIN and mortality increased with increasing risk score (p < 0.001 and p = 0.001, respectively). The all-cause in-hospital mortality rate was 13.1%, and the mortality rates for patients with and without CIN (p < 0.001) were 47.1% and 9.9%, respectively. Conclusion: Our investigation confirmed diabetes mellitus, precontrast sCr >1.5 mg/dL and acute hypotension as risk factors for CIN, and also developed a simple risk score for elderly patients seen in the ED.