Clinical and economic outcomes of assigning percutaneous coronary intervention patients to contrast-sparing strategies based on the predicted risk of contrast-induced acute kidney injury

Abstract

Objective

Contrast-sparing strategies have been developed for percutaneous coronary intervention (PCI) patients at increased risk of contrast-induced acute kidney injury (CI-AKI), and numerous CI-AKI risk prediction models have been created. However, the potential clinical and economic consequences of using predicted CI-AKI risk thresholds for assigning patients to contrast-sparing regimens have not been evaluated. We estimated the clinical and economic consequences of alternative CI-AKI risk thresholds for assigning Medicare PCI patients to contrast-sparing strategies.

Methods

Medicare data were used to identify inpatient PCI from January 2017 to June 2021. A prediction model was developed to assign each patient a predicted probability of CI-AKI. Multivariable modeling was used to assign each patient two marginal predicted values for each of several clinical and economic outcomes based on (1) their underlying clinical and procedural characteristics plus their true CI-AKI status in the data and (2) their characteristics plus their counterfactual CI-AKI status. Specifically, CI-AKI patients above the predicted risk threshold for contrast-sparing were reassigned their no CI-AKI (counterfactual) outcomes. Expected event rates, resource use, and costs were estimated before and after those CI-AKI patients were reassigned their counterfactual outcomes. This entailed bootstrapped sampling of the full cohort.

Results

Of the 542,813 patients in the study cohort, 5,802 (1.1%) had CI-AKI. The area under the receiver operating characteristic curve for the prediction model was 0.81. At a predicted risk threshold for CI-AKI of >2%, approximately 18.0% of PCI patients were assigned to contrast-sparing strategies, resulting in (/100,000 PCI patients) 121 fewer deaths, 58 fewer myocardial infarction readmissions, 4,303 fewer PCI hospital days, $11.3 million PCI cost savings, and $25.8 million total one-year cost savings, versus no contrast-sparing strategies.

Limitations

Claims data may not fully capture disease burden and are subject to inherent limitations such as coding inaccuracies. Further, the dataset used reflects only individuals with fee-for-service Medicare, and the results may not be generalizable to Medicare Advantage or other patient populations.

Conclusions

Assignment to contrast-sparing regimens at a predicted risk threshold close to the underlying incidence of CI-AKI is projected to result in significant clinical and economic benefits.

Keywords:

• Contrast-induced acute kidney injury
• percutaneous coronary intervention
• contrast-sparing strategies
• prediction model
• outcomes

JEL CLASSIFICATION CODES:

• C53
• C5
• C
• I10
• I1
• I

Transparency

Declaration of financial/other relationships

At the time of writing, RIG was a full-time employee of, and shareholder in, Boston Scientific. AB, AMM, and LMH are full-time employees of, and shareholders in, Boston Scientific. CAS is a consultant to Boston Scientific. At the time of writing, APA was Associate Professor of Medicine, Geisel School of Medicine at Dartmouth. APA is Section Chief, Interventional Cardiology, Rush University Medical Center, Interventional Cardiology Fellowship Program Director, Associate Professor of Medicine/Cardiology, Rush College of Medicine. APA was not compensated for his participation in this study. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose. Two Editorial Board Members helped with adjudicating the final decision on this paper.

Author contributions

All authors meet the International Committee of Medical Journal Editors authorship guidelines and have reviewed and agree with the content of the article.

Additional information

Funding

This research was funded by Boston Scientific.