Contrast-associated acute kidney injury is a myth: We are not sure

Influence of contrast medium on long-term renal function and outcomes in patients with septic acute kidney injury: A propensity-matched cohort study

PURPOSE

To investigate the relationship between contrast medium administration and long-term mortality and renal function in patients with septic acute kidney injury (AKI).

MATERIALS AND METHODS

We performed a retrospective, propensity-matched cohort study involving 1521 adult patients admitted with septic shock. Patients with septic AKI who underwent contrast or non-contrast CT scans were enrolled. The primary outcomes were the rates of 90-day mortality and dialysis within 90 days. The secondary outcomes included worsening of AKI, in-hospital mortality, and maintenance of dialysis after 90 days.

RESULTS

During the study period, 609 patients with septic AKI were identified; 220 (36.1%) underwent contrast CT and 389 (63.9%) underwent non-contrast CT. After propensity score matching, 133 pairs were obtained. There were no significant differences between the contrast and non-contrast CT groups in 90-day mortality (54.9% vs. 58.6%, P = 0.579), dialysis within 90 days (6.8% vs. 8.3%, P = 0.655), worsening AKI (2.3% vs. 3.0%, P = 0.706), in-hospital mortality (10.6% vs. 14.4%, P = 0.369), or maintenance of dialysis after 90 days (0.0% vs. 0.8%, P > 0.99).

CONCLUSIONS

The administration of intravenous contrast medium was not associated with long-term mortality, deterioration of renal function, or dialysis in patients with septic AKI.

Just give the contrast? Appraisal of guidelines on intravenous iodinated contrast media use in patients with kidney disease

OBJECTIVE

To appraise the quality of guidelines on intravenous iodinated contrast media (ICM) use in patients with kidney disease, and to compare the recommendations among them.

METHODS

We searched four literature databases, eight guideline libraries, and ten homepages of radiological societies to identify English and Chinese guidelines on intravenous ICM use in patients with kidney disease published between January 2018 and June 2023. The quality of the guidelines was assessed with the Scientific, Transparent, and Applicable Rankings (STAR) tool.

RESULTS

Ten guidelines were included, with a median STAR score of 46.0 (range 28.5-61.5). The guidelines performed well in "Recommendations" domain (31/40, 78%), while poor in "Registry" (0/20, 0%) and "Protocol" domains (0/20, 0%). Nine guidelines recommended estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2 as the cutoff for referring patients to discuss the risk-benefit balance of ICM administration. Three guidelines further suggested that patients with an eGFR < 45 mL/min/1.73 m2 and high-risk factors also need referring. Variable recommendations were seen in the acceptable time interval between renal function test and ICM administration, and that between scan and repeated scan. Nine guidelines recommended to use iso-osmolar or low-osmolar ICM, while no consensus has been reached for the dosing of ICM. Nine guidelines supported hydration after ICM use, but their protocols varied. Drugs or blood purification therapy were not recommended as preventative means.

CONCLUSION

Guidelines on intravenous ICM use in patients with kidney disease have heterogeneous quality. The scientific societies may consider joint statements on controversial recommendations for variable timing and protocols.

CRITICAL RELEVANCE STATEMENT

The heterogeneous quality of guidelines, and their controversial recommendations, leave gaps in workflow timing, dosing, and post-administration hydration protocols of contrast-enhanced CT scans for patients with kidney diseases, calling for more evidence to establish a safer and more practicable workflow.

KEY POINTS

• Guidelines concerning iodinated contrast media use in kidney disease patients vary. • Controversy remains in workflow timing, contrast dosing, and post-administration hydration protocols. • Investigations are encouraged to establish a safer iodinated contrast media use workflow.

Renal outcomes following intravenous contrast administration in patients with acute kidney injury: a multi-site retrospective propensity-adjusted analysis

PURPOSE

Evidence of an association between intravenous contrast media (CM) and persistent renal dysfunction is lacking for patients with pre-existing acute kidney injury (AKI). This study was designed to determine the association between intravenous CM administration and persistent AKI in patients with pre-existing AKI.

METHODS

A retrospective propensity-weighted and entropy-balanced observational cohort analysis of consecutive hospitalized patients ≥ 18 years old meeting Kidney Disease Improving Global Outcomes (KDIGO) creatinine-based criteria for AKI at time of arrival to one of three emergency departments between 7/1/2017 and 6/30/2021 who did or did not receive intravenous CM. Outcomes included persistent AKI at hospital discharge and initiation of dialysis within 180 days of index encounter.

RESULTS

Our analysis included 14,449 patient encounters, with 12.8% admitted to the intensive care unit (ICU). CM was administered in 18.4% of all encounters. AKI resolved prior to hospital discharge for 69.1%. No association between intravenous CM administration and persistent AKI was observed after unadjusted multivariable logistic regression modeling (OR 1; 95% CI 0.89-1.11), propensity weighting (OR 0.93; 95% CI 0.83-1.05), and entropy balancing (OR 0.94; 95% CI 0.83-1.05). Sub-group analysis in those admitted to the ICU yielded similar results. Initiation of dialysis within 180 days was observed in 5.4% of the cohort. An association between CM administration and increased risk of dialysis within 180 days was not observed.

CONCLUSION

Among patients with pre-existing AKI, contrast administration was not associated with either persistent AKI at hospital discharge or initiation of dialysis within 180 days. Current consensus recommendations for use of intravenous CM in patients with stable renal disease may also be applied to patients with pre-existing AKI.

Contrast-induced acute kidney injury and its contemporary prevention

The complexity and application range of interventional and diagnostic procedures using contrast media (CM) have recently increased. This allows more patients to undergo procedures that involve CM administration. However, the intrinsic CM toxicity leads to the risk of contrast-induced acute kidney injury (CI-AKI). At present, effective therapy of CI-AKI is rather limited. Effective prevention of CI-AKI therefore becomes crucially important. This review presents an in-depth discussion of CI-AKI incidence, pathogenesis, risk prediction, current preventive strategies, and novel treatment possibilities. The review also discusses the difference between CI-AKI incidence following intraarterial and intravenous CM administration. Factors contributing to the development of CI-AKI are considered in conjunction with the mechanism of acute kidney damage. The need for ultimate risk estimation and the prediction of CI-AKI is stressed. Possibilities of CI-AKI prevention is evaluated within the spectrum of existing preventive measures aimed at reducing kidney injury. In particular, the review discusses intravenous hydration regimes and pre-treatment with statins and N-acetylcysteine. The review further focuses on emerging alternative imaging technologies, alternative intravascular diagnostic and interventional procedures, and new methods for intravenous hydration guidance; it discusses the applicability of those techniques in complex procedures and their feasibility in current practise. We put emphasis on contemporary interventional cardiology imaging methods, with a brief discussion of CI-AKI in non-vascular and non-cardiologic imaging and interventional studies.

Improving Cancer Care for Patients With CKD: The Need for Changes in Clinical Trials

Chemotherapeutic agents used to treat cancer generally have narrow therapeutic indices along with potentially serious adverse toxicities. Many cancer drugs are at least partially excreted through the kidney and, thus, the availability of accurate data on safe and effective dosing of these drugs in patients with chronic kidney disease (CKD) is essential to guide treatment decisions. Typically, during drug development, initial clinical studies only include patients with normal or only mildly impaired kidney function. In subsequent preregistration studies, a limited number of patients with more severe kidney dysfunction are included. Data obtained from patients with either severe kidney dysfunction (here defined as an estimated glomerular filtration rate [eGFR] < 30 ml/min or stage 4G CKD) or end-stage kidney disease (ESKD) requiring kidney replacement treatment are particularly limited before drug registration and only a minority of new drug applications to the US Food and Drug Administration (FDA) include data from this population. Unfortunately, limited data and/or other safety concerns may result in a manufacturer statement that the drug is contraindicated in patients with advanced kidney disease, which hinders access to potentially beneficial drugs for these patients. This systemic exclusion of patients with CKD from cancer drug trials remains an unsolved problem, which prevents provision of optimal clinical care for these patients, raises questions of inclusion, diversity, and equity. In addition, with the aging of the population, there are increasing numbers of patients with CKD and cancer who face these issues. In this review, we evaluate the scientific basis to exclude patients with CKD from cancer trials and propose a comprehensive strategy to address this problem.

Intravenous CT Contrast Media and Acute Kidney Injury: A Multicenter Emergency Department-based Study

Background Although the historical risk of acute kidney injury (AKI) after intravenous administration of contrast media might be overstated, the risk in patients with impaired kidney function remains a concern. Purpose To investigate whether intravenous contrast media administration during CT is associated with a higher risk of AKI and further hemodialysis compared with the risk in patients undergoing unenhanced CT. Materials and Methods This retrospective study evaluated patients who underwent contrast-enhanced or unenhanced CT in five Taiwanese emergency departments between 2009 and 2016. The outcomes were AKI within 48-72 hours after CT, AKI within 48 hours to 1 week after CT, or further hemodialysis within 1 month after CT. The associations between contrast media exposure and outcome were estimated by using an overlap propensity score weighted generalized regression model. Subgroup analyses were performed according to the estimated glomerular filtration rate (eGFR). Results The study included 68 687 patients (median age, 68 years; interquartile range, 53-74 years; 39 995 men) with (n = 31 103) or without (n = 37 584) exposure to contrast media. After propensity score weighting, contrast media exposure was associated with higher risk of AKI within 48-72 hours after CT (odds ratio [OR], 1.16; 95% CI: 1.04, 1.29; P = .007) but no significant risk at 48 hours to 1 week after CT (OR, 1.00; 95% CI: 0.93, 1.08; P = .90). Among patients with eGFR less than 30 mL/min/1.73 m², exposure to contrast media was associated with a higher AKI risk (48-72 hours after CT: OR, 1.36; 95% CI: 1.09, 1.70; P = .007) (48 hours-1 week after CT: OR, 1.49; 95% CI: 1.27, 1.74; P < .001) and a higher risk of hemodialysis (OR, 1.36; 95% CI: 1.09, 1.70; P = .008). For patients with eGFR greater than 45 mL/min/1.73.m², contrast media exposure was not associated with higher AKI risk (P > .05). Conclusion Contrast-enhanced CT was associated with higher risk of acute kidney injury and further hemodialysis among Taiwanese patients with an estimated glomerular filtration rate (eGFR) of less than 30 mL/min/1.73 m² but not those with an eGFR of more than 45 mL/min/1.73 m². © RSNA, 2021 Online supplemental material is available for this article.

Development and Validation of a Nomogram for Predicting Drug-Induced Acute Kidney Injury in Hospitalized Patients: A Case-Control Study Based on Propensity-Score Matching

Background: Drug-induced acute kidney injury (D-AKI) is associated with increased mortality and longer hospital stays. This study aims to establish a nomogram to predict the occurrence of D-AKI in hospitalized patients in a multi-drug environment.

Methods: A single center retrospective study among adult hospitalized patients was conducted from July 2019 to September 2019 based on the Adverse Drug Events Active Surveillance and Assessment System-2 developed by our hospital. According to the propensity score matching algorithm, four controls per case were matched to eliminate the confounding bias caused by individual baseline variables. The predictors for D-AKI were obtained by logistic regression equation and used to establish the nomogram.

Results: Among 51,772 hospitalized patients, 332 were diagnosed with D-AKI. After matching, 288 pairs and 1,440 patients were included in the study, including 1,005 cases in the development group and 435 cases in the validation group. Six variables were independent predictors for D-AKI: alcohol abuse, the concurrent use of nonsteroidal anti-inflammatory drugs or diuretics, chronic kidney disease, lower baseline red blood cell count and neutrophil count ≥7 × 10⁹/L. The area under the curve (AUC) of the prediction model in the development group and validation group were 0.787 (95%CI, 0.752–0.823) and 0.788 (95%CI, 0.736–0.840), respectively. The GiViTI calibration belts showed that the model had a good prediction accuracy for the occurrence of D-AKI (p > 0.05).

Conclusion: This nomogram can help identify patients at high risk of D-AKI, which was useful in preventing the progression of D-AKI and treating it in the early stages.

Contrast-induced acute kidney injury in acute ischaemic stroke patients

PURPOSE

The potential nephrotoxicity of intravenous iodinated contrast media is a major concern for acute ischaemic stroke imaging evaluation. This study aimed to assess the incidence of acute kidney injury after intravenous iodinated contrast media exposure in acute ischaemic stroke patients.

METHODS

We conducted a retrospective cohort analysis between January 2012 and July 2018 to select adult patients admitted to the emergency department with acute ischaemic stroke. The exposed patients received a uniform intravenous dose of low osmolar non-ionic iodinated contrast media, as part of the imaging protocol for acute ischaemic stroke. The unexposed patients underwent a non-enhanced cranial computed tomography scan. Acute kidney injury was defined according to the Kidney Disease Improving Global Outcomes criteria, limited to the first 72 hours.

RESULTS

A total of 161 and 105 patients were included in the exposed and unexposed groups, respectively. The median age was 72.8 years (interquartile range 20), 53% were men and 97% were white. Demographic and baseline characteristics were similar between the groups. The incidence of acute kidney injury between exposed (n = 10, 6.2%) and unexposed (n = 1, 1%) groups (P = 0.073) was similar and contrast exposure was not a significant predictor of acute kidney injury.

CONCLUSION

Intravenous iodinated contrast media exposure during acute ischaemic stroke imaging protocols is not an independent predictor of acute kidney injury in patients with normal or near-normal renal function. Studies with larger sample sizes would help to clarify if patients with both cardiovascular risk factors and impaired renal function could benefit from prophylactic measures.

Quality of care after AKI development in the hospital: Consensus from the 22nd Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

Acute kidney injury (AKI) is independently associated with increased morbidity and mortality. Quality improvement has been identified as an important goal in the care of patients with AKI. Different settings can be targeted to improve AKI care, broadly classified these include the inpatient and outpatient environments. In this paper, we will emphasize quality indicators associated with the management and secondary prevention of AKI in hospitalized patients to limit the severity, duration, and complications.

METHODS

During the 22nd Acute Disease Quality Initiative (ADQI) consensus conference, a multidisciplinary group of experts discussed the evidence and used a modified Delphi process to achieve consensus on recommendations for AKI-related quality indicators (QIs) and care processes to improve patient outcomes. The management and secondary prevention of AKI in hospitalized patients were discussed, and recommendations were summarized.

RESULTS

The first step in optimizing the quality of AKI management is the determination of baseline performance. Data regarding each institution's/center's performance can provide a reference point from which to benchmark quality efforts. Quality program initiatives should prioritize achievable goals likely to have the highest impact according to the setting and context. Key AKI quality metrics should include improvement in timely recognition, appropriate diagnostic workup, and implementation of known interventions that limit progression and severity, facilitating recovery, and mitigating AKI-associated complications. We propose the Recognition-Action-Results framework to plan, measure, and report the progress toward improving AKI management quality.

CONCLUSIONS

These recommendations identified and outlined an approach to define and evaluate the quality of AKI management in hospitalized patients.

Point-of-care creatinine tests to assess kidney function for outpatients requiring contrast-enhanced CT imaging: systematic reviews and economic evaluation

BACKGROUND

Patients with low estimated glomerular filtration rates may be at higher risk of post-contrast acute kidney injury following contrast-enhanced computed tomography imaging. Point-of-care devices allow rapid measurement of estimated glomerular filtration rates for patients referred without a recent estimated glomerular filtration rate result.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of point-of-care creatinine tests for outpatients without a recent estimated glomerular filtration rate measurement who need contrast-enhanced computed tomography imaging.

METHODS

Three systematic reviews of test accuracy, implementation and clinical outcomes, and economic analyses were carried out. Bibliographic databases were searched from inception to November 2018. Studies comparing the accuracy of point-of-care creatinine tests with laboratory reference tests to assess kidney function in adults in a non-emergency setting and studies reporting implementation and clinical outcomes were included. Risk of bias of diagnostic accuracy studies was assessed using a modified version of the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Probabilities of individuals having their estimated glomerular filtration rates correctly classified were estimated within a Bayesian framework and pooled using a fixed-effects model. A de novo probabilistic decision tree cohort model was developed to characterise the decision problem from an NHS and a Personal Social Services perspective. A range of alternative point-of-care testing approaches were considered. Scenario analyses were conducted.

RESULTS

Fifty-four studies were included in the clinical reviews. Twelve studies reported diagnostic accuracy for estimated glomerular filtration rates; half were rated as being at low risk of bias, but there were applicability concerns for most. i-STAT (Abbott Point of Care, Inc., Princeton, NJ, USA) and ABL (Radiometer Ltd, Crawley, UK) devices had higher probabilities of correctly classifying individuals in the same estimated glomerular filtration rate categories as the reference laboratory test than StatSensor® devices (Nova Biomedical, Runcorn, UK). There was limited evidence for epoc® (Siemens Healthineers AG, Erlangen, Germany) and Piccolo Xpress® (Abaxis, Inc., Union City, CA, USA) devices and no studies of DRI-CHEM NX 500 (Fujifilm Corporation, Tokyo, Japan). The review of implementation and clinical outcomes included six studies showing practice variation in the management decisions when a point-of-care device indicated an abnormal estimated glomerular filtration rate. The review of cost-effectiveness evidence identified no relevant studies. The de novo decision model that was developed included a total of 14 strategies. Owing to limited data, the model included only i-STAT, ABL800 FLEX and StatSensor. In the base-case analysis, the cost-effective strategy appeared to be a three-step testing sequence involving initially screening all individuals for risk factors, point-of-care testing for those individuals with at least one risk factor, and including a final confirmatory laboratory test for individuals with a point-of-care-positive test result. Within this testing approach, the specific point-of-care device with the highest net benefit was i-STAT, although differences in net benefit with StatSensor were very small.

LIMITATIONS

There was insufficient evidence for patients with estimated glomerular filtration rates < 30 ml/minute/1.73 m2, and on the full potential health impact of delayed or rescheduled computed tomography scans or the use of alternative imaging modalities.

CONCLUSIONS

A three-step testing sequence combining a risk factor questionnaire with a point-of-care test and confirmatory laboratory testing appears to be a cost-effective use of NHS resources compared with current practice. The risk of contrast causing acute kidney injury to patients with an estimated glomerular filtration rate of < 30 ml/minute/1.73 m2 is uncertain. Cost-effectiveness of point-of-care testing appears largely driven by the potential of point-of-care tests to minimise delays within the current computed tomography pathway.

FUTURE WORK

Studies evaluating the impact of risk-stratifying questionnaires on workflow outcomes in computed tomography patients without recent estimated glomerular filtration rate results are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018115818.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 39. See the NIHR Journals Library website for further project information.

Use of Intravenous Iodinated Contrast Media in Patients with Kidney Disease: Consensus Statements from the American College of Radiology and the National Kidney Foundation

Intravenous iodinated contrast media are commonly used with CT to evaluate disease and to determine treatment response. The risk of acute kidney injury (AKI) developing in patients with reduced kidney function following exposure to intravenous iodinated contrast media has been overstated. This is due primarily to historic lack of control groups sufficient to separate contrast-induced AKI (CI-AKI; ie, AKI caused by contrast media administration) from contrast-associated AKI (CA-AKI; ie, AKI coincident to contrast media administration). Although the true risk of CI-AKI remains uncertain for patients with severe kidney disease, prophylaxis with intravenous normal saline is indicated for patients who have AKI or an estimated glomerular filtration rate less than 30 mL/min/1.73 m² who are not undergoing maintenance dialysis. In individual high-risk circumstances, prophylaxis may be considered in patients with an estimated glomerular filtration rate of 30-44 mL/min/1.73 m² at the discretion of the ordering clinician. This article is a simultaneous joint publication in Radiology and Kidney Medicine. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article.

Use of Intravenous Iodinated Contrast Media in Patients With Kidney Disease: Consensus Statements from the American College of Radiology and the National Kidney Foundation

Intravenous iodinated contrast media are commonly used with CT to evaluate disease and to determine treatment response. The risk of acute kidney injury (AKI) developing in patients with reduced kidney function following exposure to intravenous iodinated contrast media has been overstated. This is due primarily to historic lack of control groups sufficient to separate contrast-induced AKI (CI-AKI; ie, AKI caused by contrast media administration) from contrast-associated AKI (CA-AKI; ie, AKI coincident to contrast media administration). Although the true risk of CI-AKI remains uncertain for patients with severe kidney disease, prophylaxis with intravenous normal saline is indicated for patients who have AKI or an estimated glomerular filtration rate less than 30 mL/min/1.73 m² who are not undergoing maintenance dialysis. In individual high-risk circumstances, prophylaxis may be considered in patients with an estimated glomerular filtration rate of 30-44 mL/min/1.73 m² at the discretion of the ordering clinician.

Association between intravenous contrast media exposure and non-recovery from dialysis-requiring septic acute kidney injury: a nationwide observational study

PURPOSE

This study aimed to examine the association between the use of intravenous contrast and non-recovery from dialysis-requiring acute kidney injury (AKI-D) and in-hospital mortality among patients with sepsis.

METHODS

This was a retrospective observational study using the Japanese Diagnosis Procedure Combination inpatient database between January 2011 and December 2016. We identified patients with septic AKI who began continuous renal replacement therapy (RRT) within 2-days of admission and underwent computed tomography. We compared patients with AKI-D with and without the use of intravenous contrast for computed tomography and performed propensity score matching to adjust for confounders for the association between exposure to intravenous contrast and outcomes, including a composite outcome of in-hospital mortality and RRT dependence at discharge and RRT duration.

RESULTS

From 3782 and 6619 patients with septic AKI-D with and without intravenous contrast exposure, respectively, 3485 propensity score-matched pairs were generated. No significant differences were found in the outcomes between the propensity score-matched groups: a composite outcome of in-hospital mortality and RRT dependence, 49.6% vs. 50.2% (odds ratio (OR) 0.98; 95% CI (confidence interval) 0.88, 1.07); in-hospital mortality, 45.3% vs. 46.1% (OR 0.97; 95% CI 0.87, 1.06); RRT dependence, 4.4% vs 4.1% (OR 1.08; 95% CI 0.85, 1.31); and median (interquartile range) of RRT duration, 4 [2-11] days vs. 4 [2-11] days (P = 0.58).

CONCLUSIONS

This large observational study did not support an association between intravenous contrast media and adverse in-hospital outcomes in patients with septic AKI-D. Further studies are warranted to assess the generalizability.

Acute kidney injury following contrast media administration in the septic patient: A retrospective propensity-matched analysis

PURPOSE

To determine the risk for acute kidney injury (AKI) attributable to intravenous contrast media (CM) administration in septic patients.

MATERIALS AND METHODS

This was a single-center retrospective propensity matched cohort analysis performed in the emergency department (ED) of an academic medical center. All visits for patients ≥18 years who met sepsis diagnostic criteria and had serum creatinine (SCr) measured both on arrival to the ED and again 48 to 72 h later were included. Of 4171 visits, 1464 patients underwent contrast-enhanced CT (CECT), 976 underwent unenhanced CT and 1731 underwent no CT at all.

RESULTS

The primary outcome was incidence of AKI. Logistic regression and between-groups odds ratios with and without propensity-score matching were used to test for an independent association between CM administration and AKI. Incidence of AKI was 7.2%, 9.4% and 9.7% in those who underwent CECT, unenhanced CT and no CT. CM administration was not associated with increased incidence of AKI.

CONCLUSIONS

Sepsis is a medical emergency proven to benefit from early diagnosis and rapid initiation of treatment, which is often aided by CECT. Our findings argue against withholding CM for fear of precipitating AKI in potentially septic patients.