Epic Cosmos to Describe AKI Events in Acute Heart Failure

Background: The prevalence of acute kidney injury (AKI) in acute heart failure (AHF) is highly variable (10-30%). How AKI in AHF is defined in the literature is also highly variable. AKI prevalence and applicability of AKI definitions to real-world data is unknown. We aimed to explore the types of data that could be leveraged to answer questions about AKI in AHF using data from Cosmos, a collaborative Epic health systems database with longitudinal healthcare records for 298 million patients. Methods: Diagnoses and laboratory values were queried using ICD-10-CM and LOINC codes, respectively. All adult hospitalizations from 2017-2024 with a primary diagnosis of AHF were included. Patients had ≥1 outpatient serum creatinine (sCr) in the 12 months prior to admission (the average of which we called baseline sCr), and ≥1 sCr value during the admission. We defined four sub-cohorts: (1) hospitalizations with AKI by ICD-10-CM code N17.* (AKI-ICD), (2) hospitalizations with Stage 1 AKI per KDIGO criteria, (3) hospitalizations with Stage 2/3 AKI per KDIGO criteria (mutually exclusive), and (4) No-AKI. Results: There were 606,131 AHF admissions attributable to 446,341 unique patients during the inclusion period. 40% had AKI by ICD-10 code; 43% had AKI by KDIGO criteria (Figure 1A). Only 6% had KDIGO stage 2/3 AKI. The positive predictive value of AKI-ICD was 72%; the negative predictive value was 77% (Figure 1B). sCr trajectories by AKI subgroup are shown in Figure 1C. Data on overall mortality, inpatient nephrology consults, and outpatient nephrology referrals were unreliably stored in Cosmos. Conclusion: This analysis demonstrated that Cosmos may be a valuable resource of real-world data that can be used to evaluate kidney outcomes in AHF. There is granular data on repeated kidney function measures, medications, and in-hospital outcomes. Data are lacking on out-of-hospital mortality and nephrology consults. Funding: Other NIH Support - 5KL2TR003981, UL1TR003163