Impact of acute kidney injury on in-hospital outcomes among patients hospitalized with acute heart failure: a propensity score matched analysis

Background Acute kidney injury (AKI) is frequently present in patients admitted for acute heart failure (AHF). Several studies have evaluated the mortality risk and have concluded poor prognosis in any patient with AKI admitted for AHF. For the most part, the additional morbidity and mortality burden in AHF patients with AKI has been attributed to the concomitant comorbidities, and/or interventions. Purpose We sought to determine the impact of acute kidney injury (AKI) on in-hospital outcomes in patients presenting with acute heart failure (AHF). We identified isolated AKI patients after excluding other concomitant diagnoses and procedures, which may contribute to an increased risk of mortality and morbidity. Methods Data from the National Inpatient Sample (2012- 14) were used to identify patients with the principal diagnosis of AHF and the concomitant secondary diagnosis of AKI. Propensity score matching was performed on 30 baseline variables to identify a matched cohort. The outcome of interest was in-hospital mortality. We further evaluated in-hospital procedures and complications. Results Of 1,470,450 patients admitted with AHF, 24.3% had AKI. After propensity matching a matched cohort of 356,940 patients was identified. In this matched group, the AKI group had significantly higher in-hospital mortality (3.8% vs 1.7%, p<0.001). Complications such as sepsis and cardiac arrest were higher in the AKI group. Similarly, in-hospital procedures including CABG, mechanical ventilation and IABP were performed more in the AKI group. AHF patients with AKI had longer in-hospital stay of ∼1.7 days. Conclusions In a propensity score-matched cohort of AHF with and without AKI, the risk of in-hospital mortality was >2-fold in the AKI group. Healthcare utilization and burden of complications were higher in the AKI group. Funding Acknowledgement Type of funding source: None