Acute Kidney Injury After Computed Tomography: A Meta-analysis

Study objective: Computed tomography (CT) is an important imaging modality used in the diagnosis of a variety of disorders. Imaging quality may be improved if intravenous contrast is added, but there is a concern for potential renal injury. Our goal is to perform a meta-analysis to compare the risk of acute kidney injury, need for renal replacement, and total mortality after contrast-enhanced CT versus noncontrast CT. Methods: We searched MEDLINE (PubMed), the Cochrane Library, CINAHL, Web of Science, ProQuest, and Academic Search Premier for relevant articles. Included articles specifically compared rates of renal insufficiency, need for renal replacement therapy, or mortality in patients who received intravenous contrast versus those who received no contrast. Results: The database search returned 14,691 articles, inclusive of duplicates. Twenty-six unique articles met our inclusion criteria, with an additional 2 articles found through hand searching. In total, 28 studies involving 107,335 participants were included in the final analysis, all of which were observational. Meta-analysis demonstrated that, compared with noncontrast CT, contrast-enhanced CT was not significantly associated with either acute kidney injury (odds ratio [OR] 0.94; 95% confidence interval [CI] 0.83 to 1.07), need for renal replacement therapy (OR 0.83; 95% CI 0.59 to 1.16), or all-cause mortality (OR 1.0; 95% CI 0.73 to 1.36). Conclusion: We found no significant differences in our principal study outcomes between patients receiving contrast-enhanced CT versus those receiving noncontrast CT. Given similar frequencies of acute kidney injury in patients receiving noncontrast CT, other patient- and illness-level factors, rather than the use of contrast material, likely contribute to the development of acute kidney injury.