[Risk and harm of contrast induced nephropathy in critically ill patients]

Abstract

Objective: To assess whether intravenous contrast medium would result in acute kidney injury (AKI), and to determine the risk factors associated with contrast induced AKI (CI-AKI) and its outcome.

Methods: A retrospective observational study was conducted in intensive care unit (ICU) of Fuyang People's Hospital in Zhejiang Province from January 1st 2011 to December 31st 2014. All enrolled critically ill patients had accepted CT scan, and the hospital length of stay was longer than 48 hours, and the patients who needed renal replacement treatment were excluded. Patients were divided into contrast medium group and control group. AKI was defined according to Acute Kidney Injury Network (AKIN) criteria ( serum creatinine content over 26.4 μmol/L or 50% increase of it from baseline within 48 hours). The incidence of AKI was compared between the two groups, and risk factors for CI-AKI were determined by multiple logistic regression analysis. The relationship of CI-AKI and outcomes were also analyzed.

Results: A total of 2 370 critically ill patients were enrolled during the period. 474 (20.0%) of the 2 370 patients received contrast medium, and 70 of them suffered from CI-AKI ( 14.8% ). In 1 896 patients who did not receive contrast medium, 235 of them suffered from AKI (12.4%). There was no significant difference in the incidence of AKI between two groups ( χ² = 1.905, P = 0.168). After several confounding factors were adjusted, multiple logistic regression analysis showed that contrast medium was not found to associate with AKI in critically ill patients [ odds ratio (OR) = 1.66, 95% confidence interval ( 95%CI) = 0.72-3.90,P = 0.201 ], and high acute physiology and chronic health evaluation II ( APACHEII) score ( OR = 1.70, 95%CI = 1.33-2.40, P < 0.001), sepsis (OR = 8.06, 95%CI = 3.28-17.80, P < 0.001), shock (OR = 3.57, 95%CI = 1.73-8.01, P < 0.001) and use of nephrotoxic agent (OR = 1.96, 95%CI = 1.25-2.63, P = 0.015) were risk factors of CI-AKI. Ten of 70 patients with CI-AKI died (14.3%), and 21 out of 404 patients without CI-AKI, died (5.2%). There was no significant difference in the mortality rate (χ² = 8.060, P = 0.005 ). It was shown by multiple logistic regression analysis that age (OR=1.30, 95%CI = 1.05-1.71, P = 0.027), male sex (OR = 1.13, 95%CI = 1.05-1.20, P = 0.039), APACHEII score (OR = 1.07, 95%CI = 1.03-1.18, P < 0.001), and sepsis ( OR = 3.29, 95%CI = 1.92-6.46, P < 0.001) were highly associated with mortality of critically ill patients in whom contrast medium was used. However, the occurrence of CI-AKI showed no influence on the mortality rate (OR = 1.70, 95%CI = 0.88-3.56, P = 0.227).

Conclusions: The use of contrast medium is not a risk factor of CI-AKI in critically ill patients. CI-AKI will not raise mortality rate in ICU patients.