Outcomes, risk factors and health burden of contrast-induced acute kidney injury: an observational study of one million hospitalizations with image-guided cardiovascular procedures.

BACKGROUND: Despite the use of low-osmolar contrast media that have significantly reduced the occurrence of severe adverse reactions, contrast-induced (CI) acute kidney injury (AKI) remains the third cause of AKI in hospitals. We sought to estimate the frequency of CI-AKI among hospitalized patients undergoing image-guided cardiovascular procedures, to quantify the effect of risk factors on the development of this complication and to assess relative organizational and economic burden in healthcare.

METHODS: A retrospective cross-sectional population-based study using the extensive French hospital discharge database (PMSI) was carried out. Hospitalizations with image-guided cardiovascular procedures using a contrast media were identified in adults over a 2-year period (2012-2013). Suspected CI-AKI was defined as the presence, during hospitalization, of a diagnostic code of AKI (International Classification of Diseases, 10th revision [ICD-10] codes: N141, 142, N144, N990, N17, N19 or R392) or a code of renal replacement therapy procedure (Classification Commune des Actes Médicaux [CCAM] codes: JVJB001, JVJF002-005 and JVJF008) as creatinine criteria were not available.

RESULTS: During 1,047,329 hospitalizations studied, 32,308 suspected CI-AKI were observed, yielding a frequency of 3.1 %. By multivariate analysis, factors that significantly increased the risk of suspected CI-AKI included cardiogenic shock (odds ratio [OR] = 20.5, 95 % confidence interval [95 % CI] [18.7; 22.5]), acute heart failure (OR = 2.5, 95 % CI [2.4; 2.6]) and chronic kidney disease (OR = 2.3, 95 % CI [2.2; 2.3]. Renal replacement therapy was initiated during 6,335 (0.6 %) hospitalizations. The mean length of stay and cost of hospitalizations associated with suspected CI-AKI was higher than in hospitalizations without suspected CI-AKI (20.5 vs 4.7 days, p < 0.00001 and €15,765 vs €3,352, p < 0.0001, respectively).

CONCLUSIONS: This is the first large-scale population-based study to estimate frequency and health burden of suspected CI-AKI occurring after image-guided cardiovascular procedures, and the first available data in a French population. We showed that this iatrogenic complication remains of high concern despite prevention efforts and contrast media product improvement. From our results, suspected CI-AKI is associated with particularly high mortality, significantly extends hospitalizations, and leads to additional costs reaching a total of €200M per year.