Risk of acute kidney injury after contrast-enhanced computerized tomography: a systematic review and meta-analysis of 21 propensity score-matched cohort studies

Abstract

Objectives: Intravenous application of contrast media is part of a wide spectrum of diagnostic procedures for better imaging quality. Clinical avoidance of contrast-enhanced imaging is an ever-present quandary in patients with impaired kidney function. The objective of this study was to estimate the risk for acute kidney injury (AKI), dialysis and mortality among patients undergoing contrast-enhanced CT compared to propensity score-matched controls (i.e. contrast-unenhanced CT). Selected cohort studies featured high-risk patients with advanced kidney disease and critical illness.

Methods: This review was designed to conform to the Preferred Reporting Items in Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed was searched from August 2021 to November 2021 for all-language articles without date restriction. A random-effects model (DerSimonian and Laird method) was used for meta-analysis.

Results: Twenty-one articles were included, comprising data of 169,455 patients. The overall risk of AKI was similar in the contrast-enhanced and unenhanced groups (OR: 0.97 [95% CI: 0.85; 1.11], p = 0.64), regardless of baseline renal function and underlying disease. Substantial heterogeneity was detected (I² = 90%, p ≤ 0.0001). Multivariable logistic regression identified hypertension (p = 0.03) and estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m² (p = 0.0001) as factors associated with greater risk of post-contrast AKI.

Conclusions: Based on propensity score-matched pairs obtained from 21 cohort studies, we found no evidence for increased risk for AKI, dialysis or mortality after contrast-enhanced CT among patients with eGFR ≥ 45 mL/min/1.73 m². In congruence with the emerging evidence in the literature, caution should be exercised in patients with hypertension and eGFR ≤ 30 mL/min/1.73 m².

Key points: • The application of contrast media for medical imaging is not associated with higher odds for AKI, induction of renal replacement therapy, or mortality. Many comorbidities traditionally associated with greater risk for acute kidney injury do not appear to predispose for renal decline after contrast media exposure. • Underlying hypertension and eGFR less than or equal to 30 mL/min/1.73 m² seem to predispose for post-contrast acute kidney injury. • Propensity score matching cannot account for unmeasured influences on AKI incidence, which needs to be addressed in the interpretation of results.

Keywords: Acute kidney injury; Computed tomography; Contrast media; Glomerular filtration rate; Propensity score matching.

Fig. 1

Flowchart showing the study selection process. The numbers of studies identified, assessed for eligibility, and included in the meta-analysis

Fig. 2

Forest plot with overall odds ratio (OR) of the association of CM application and AKI. 95%-CI, 95% confidence interval; CM, contrast media

Fig. 3

Forest plot with overall odds ratio (OR) of the association of CM application and AKI in patients with eGFR ≤ 30. 95%-CI, 95% confidence interval; CM, contrast media

Fig. 4

Balloon plot with log odds ratio (OR) of the association of CM application and AKI in patients with hypertension. 95%-CI, 95% confidence interval; CM, contrast media