Frequency of acute kidney injury following intravenous contrast medium administration: a systematic review and meta-analysis.

PURPOSE To perform a systematic review and meta-analysis of controlled studies examining the incidence of acute kidney injury (AKI) and other outcomes in patients exposed to intravenous (i.v.) contrast medium compared with patients who underwent an imaging examination without contrast medium or were otherwise unexposed (control group). MATERIALS AND METHODS MEDLINE, EMBASE, Scopus, and the Cochrane Library were searched for all articles published through September 2011 that contained search terms related to nephrotoxicity following intravenous contrast medium administration. Two independent reviewers identified studies in which the incidence of AKI in patients exposed to i.v. contrast medium was directly compared with the incidence of AKI in unexposed patients through analysis of changes in serum creatinine level or estimated glomerular filtration rate 48-72 hours following imaging procedures or admission. Study characteristics and outcomes of AKI, dialysis, and mortality were extracted by using a standardized protocol. Relative risk (RR) was calculated by using random-effects models and was tested in subgroups of different patient comorbidities, contrast medium types, and AKI diagnostic criteria. RR results of less than 1.00 indicated that there was a higher incidence of these outcomes in the group that did not receive contrast medium (non-contrast medium group). RESULTS Of the 1489 studies originally identified, 13 nonrandomized studies (0.9%) representing 25,950 patients met inclusion criteria. In the group that received contrast medium (contrast medium group), risk of AKI (RR = 0.79; 95% confidence interval [CI]: 0.62, 1.02; P = .07), death (RR = 0.95; 95% CI: 0.55, 1.67; P = .87), and dialysis (RR = 0.88; 95% CI: 0.23, 3.43; P = .85) was similar, compared with the risk of AKI in the non-contrast medium group. This pattern was observed regardless of i.v. contrast medium type, diagnostic criteria for AKI, or whether patients had diabetes mellitus or renal insufficiency. CONCLUSION Controlled contrast medium-induced nephropathy studies demonstrate a similar incidence of AKI, dialysis, and death between the contrast medium group and control group. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121460/-/DC1.