Does intravenous contrast-enhanced computed tomography cause acute kidney injury? Protocol of a systematic review of the evidence

Abstract

BackgroundContrast-induced acute kidney injury is a common cause of iatrogenic acute kidney injury (AKI). Most of the published estimates of AKI after contrast use originate from the cardiac catheterization literature despite contrast-enhanced computed tomography (CT) scans being the more common setting for contrast use. This systematic review aims to summarize the current evidence about (1)the risk of AKI following intravenous (IV) contrast-enhanced CT scans and(2) the risk of clinical outcomes (i.e. death, hospitalization and need for renal replacement therapy) due to IV contrast-enhanced CT scans.Methods/DesignA systematic literature search for published studies will be performed using MEDLINE, EMBASE and The COCHRANE Library databases. Unpublished studies will be identified by searching through grey literature. No language restriction will be applied.The review will consider all studies that have examined the association between IV contrast media and AKI. To be selected, the study should include two arms: one group of exposed patients who received IV contrast material before CT scans and one group of unexposed group who did not receive contrast material before CT scans. Two authors will independently screen titles and abstracts obtained from electronic databases, extract data and will assess the quality of the studies selected using the Cochrane's ‘Risk of Bias’ assessment tool for randomized trials and the Newcastle-Ottawa Scale for observational studies. A random-effects meta-analysis will be performed if there is no remarkable heterogeneity between studies.DiscussionThis systematic review will provide synthesis of current evidence around the effect of IV contrast material on AKI and other clinical outcomes. Results will be helpful for making evidence-based recommendations and guidelines for clinical and radiologic settings.Systematic review registrationPROSPERO CRD42013003799.

The Controversy of Contrast-Induced Nephropathy With Intravenous Contrast: What Is the Risk?

“…All these controlled studies have major limitations, including a higher prevalence of CKD in the control patients, limited numbers of high-risk patients, and lack of adjustment for confounding variables. [44][45][46][47] CECT Controlled Studies of CIN With Propensity Score Adjustments Given the imbalance in confounding covariates and selection bias between CM and control populations, the ideal approach to determine CIN following intravenous contrast would be an RCT in patients undergoing CT with or without CM enhancement, which would ensure balanced comorbid conditions between groups and nonbiased randomization. For ethical and logistical reasons, it is unlikely that such RCTs will be performed.…”