Healthcare resource utilization and costs of persistent severe AKI among hospitalized Stage 2/3 AKI patients

Background: Persistent severe acute kidney injury (PS-AKI) is associated with worse clinical outcomes, but there is no data on costs of PS-AKI. We compared costs and healthcare resource utilization (HRU) for inpatients with PS-AKI vs. not-persistent severe AKI (NPS-AKI) overall and by ICU use. Methods: This retrospective observational study included 126,528 adult US inpatients in the PINC AI Healthcare Database (PHD), discharged from January 1, 2017, to December 31, 2019, with KDIGO stage 2 or 3 AKI (by serum creatinine [SCr] criteria) during hospitalization, length of stay (LOS) ≥3 days, and ≥3 SCr measurements. Patients were categorized as PS-AKI (defined as stage 3 AKI lasting ≥3 days or with death within 3 days or stage 2/3 AKI (by SCr criteria) with dialysis within 3 days), or NPS-AKI. Generalized linear model regression compared LOS and costs during index hospitalization (total cohort) and 30-days post-discharge (survivors of index hospitalization), adjusted for patient, hospital, and clinical characteristics. Results: Among 126,528 patients with stage 2/3 AKI, 30,916 developed PS-AKI. In adjusted models, compared to NPS-AKI, patients with PS-AKI had 32% longer total LOS (+3.3 days), 45% longer ICU LOS (+ 2.6 days), 46% higher total costs (+$13,143), 58% higher ICU costs (+$15,908), and during 30-days post-discharge, had 13% longer readmission LOS (+1.0 day), 22% higher readmission costs (+$4049), and 12% higher outpatient costs (+$206) (p<0.005 for all). Relative LOS and cost differences for PS-AKI vs. NPS-AKI were similar for ICU (n=57,947) and non-ICU (n=68,581) patients. Conclusions: Among hospitalized stage 2/3 AKI patients, PS-AKI was associated with significantly longer LOS and higher costs during index hospitalization and 30-days post-discharge, overall, and in ICU and non-ICU patients. Preventing PS-AKI among patients with stage 2/3 AKI may reduce hospital LOS and costs.