Costs and consequences of acute kidney injury after cardiac surgery: A cohort study

Abstract Objectives Acute kidney injury (AKI) is common after cardiac surgery. We quantified the mortality and costs of varying degrees of AKI using a population-based cohort in Alberta, Canada. Methods A cohort of patients undergoing cardiac surgery from 2004-2009 was assembled from linked Alberta administrative databases. AKI was classified by KDIGO stages of severity. Our outcomes were in-hospital mortality, length of stay, and costs; among survivors, we also examined mortality and costs at 365 days. Estimates were adjusted for demographics, comorbidities, and other covariates. Results 10170 were included, of whom 9771 patients were discharged to community. Overall in-hospital mortality, costs, and length of stay were 4%, 7 days, and $34 thousand, respectively. Post-cardiac surgery, AKI occurred in 25%. Compared to those without AKI, AKI was independently associated with increased in-hospital mortality across severity categories, with the highest risk (adjusted odds ratio 37.1, 95% confidence interval [CI] 26.3 to 52.1, p Conclusions AKI remains an important indicator of mortality and health care costs post-cardiac surgery.