Rate and risk factors for AKI after CT scans in a cancer cohort

Aims: The proinflammatory milieu in cancer patients may expose them to increased risk for acute kidney injury (AKI) after IV contrast (CON). The aims of this study were to determine: (1) the rates of AKI after CON and noncontrast (NC) CT scans in cancer inpatients, (2) if rates differed among cancer subtypes, and (3) whether recent chemotherapy, comorbid conditions, or nephrotoxins increase AKI after CON. Materials and methods: Retrospective data was collected on adults who had received a CON or NC CT from January 1, 2012 to December 30, 2014. AKI was defined as a > 1.5× increased baseline creatinine. Data was analyzed using Rao-Scott χ(2)-test, propensity score matching, and logistic regressions. Results: A total of 7,512 CT scans were performed in 4,456 patients (4,958 NC, 2,554 CON). The rate for AKI with CON was 7.3% and 11.4% (p < 0.001) with NC imaging. The risk of AKI increased with lower baseline eGFR: for eGFR ≤ 29 mL/min/1.73m(2), OR = 1.83 (p = 0.0002); for eGFR 30 – 59 mL/min/1.73m(2), OR = 1.5 compared to eGFR ≥ 60 mL/min/1.73m(2) (p < 0.0001). AKI rates were higher when any chemotherapy was given within 60 days of CT (OR = 1.22, p < 0.02), with congestive heart failure (OR 1.51, p = 0.0006), and history of AKI (OR 3.89, p < 0.0001). In 1:1 propensity score matched samples, the OR for AKI after CON was 0.87 (p = 0.23) compared to NC. Conclusion: In cancer patients, eGFR below 59 mL/min/1.73m(2) were associated with increased rate of AKI, independent of contrast exposure. Congestive heart failure and prior AKI were also associated with increased rates of AKI.