Outcomes, Healthcare Resource Utilization, and Costs of Overall, Community-Acquired, and Hospital-Acquired Acute Kidney Injury in COVID-19 Patients.

Background: In hospitalized patients with COVID-19, acute kidney injury (AKI) is associated with higher mortality, but data are lacking on healthcare resource utilization (HRU) and costs related to AKI, community-acquired AKI (CA-AKI), and hospital-acquired AKI (HA-AKI). Objectives: To quantify the burden of AKI, CA-AKI, and HA-AKI among inpatients with COVID-19. Methods: This retrospective cohort study included inpatients with COVID-19 discharged from US hospitals in the Premier PINC AI™ Healthcare Database April 1-October 31, 2020, categorized as AKI, CA-AKI, HA-AKI, or no AKI by ICD-10-CM diagnosis codes. Outcomes were assessed during index (initial) hospitalization and 30 days postdischarge. Results: Among 208 583 COVID-19 inpatients, 30%, 25%, and 5% had AKI, CA-AKI, and HA-AKI, of whom 10%, 7%, and 23% received dialysis, respectively. Excess mortality, HRU, and costs were greater for HA-AKI than CA-AKI. In adjusted models, for patients with AKI vs no AKI and HA-AKI vs CA-AKI, odds ratios (ORs) (95% CI) were 3.70 (3.61-3.79) and 4.11 (3.92-4.31) for intensive care unit use and 3.52 (3.41-3.63) and 2.64 (2.52-2.78) for in-hospital mortality; mean length of stay (LOS) differences and LOS ratios (95% CI) were 1.8 days and 1.24 (1.23-1.25) and 5.1 days and 1.57 (1.54-1.59); and mean cost differences and cost ratios were $7163 and 1.35 (1.34-1.36) and $19 127 and 1.78 (1.75-1.81) (all P < .001). During the 30 days postdischarge, readmission LOS was ≥6% longer for AKI vs no AKI and HA-AKI vs CA-AKI; outpatient costs were ≥41% higher for HA-AKI vs CA-AKI or no AKI. Only 30-day new dialysis (among patients without index hospitalization dialysis) had similar odds for HA-AKI vs CA-AKI (2.37-2.8 times higher for AKI, HA-AKI, or CA-AKI vs no AKI). Discussion: Among inpatients with COVID-19, HA-AKI had higher excess mortality, HRU, and costs than CA-AKI. Other studies suggest that interventions to prevent HA-AKI could decrease excess morbidity, HRU, and costs among inpatients with COVID-19. Conclusions: In adjusted models among COVID-19 inpatients, AKI, especially HA-AKI, was associated with significantly higher mortality, HRU, and costs during index admission, and higher dialysis and longer readmission LOS during the 30 days postdischarge. These findings support implementation of interventions to prevent HA-AKI in COVID-19 patients.

Clinical Outcomes of Persistent Severe Acute Kidney Injury among Patients with Kidney Disease Improving Global Outcomes Stage 2 or 3 Acute Kidney Injury.

INTRODUCTION: The burden of persistent (≥3 days) severe AKI (PS-AKI) is poorly described among inpatients with stage 2-3 AKI in the ward or ICU. Quantification could motivate targeted interventions to decrease duration of AKI in these high-risk patients. METHODS: This retrospective cohort study included adult patients discharged from January 1, 2017, to December 31, 2019, from US hospitals in the PINC AI Healthcare Database. Patients with KDIGO stage 2 or 3 AKI, length of stay ≥3 days, ≥3 serum creatinine measures, and no history of renal transplant, dialysis, or stage 5 chronic kidney disease were included. Patients were classified as PS-AKI (stage 3 AKI lasting ≥3 days or with death in ≤3 days, or stage 2 or 3 AKI with dialysis in ≤3 days) or not PS-AKI (NPS-AKI) (stage 3 AKI for ≤2 days, or stage 2 AKI without dialysis in ≤3 days). Outcomes during index (initial) hospitalization were PS-AKI incidence, ICU use, and in-hospital mortality, and during 30 days post-discharge were readmissions, in-hospital mortality, dialysis, and "new" dialysis (dialysis among patients without dialysis during index hospitalization). For index outcomes, we used a sensitivity definition, PS-AKISens, that excluded patients who met PS-AKI criteria by dialysis/death in ≤3 days of AKI onset. Multivariable-adjusted logistic regression quantified differences between PS-AKI and NPS-AKI, overall, and separately for ICU and non-ICU patients. RESULTS: Among 126,528 inpatients with stage 2 or 3 AKI, PS-AKI developed in 24.4% (30,916), with 39% of PS-AKI occurring in non-ICU patients. With NPS-AKI as the reference group, adjusted odds ratios (aORs) (95% CI) for PS-AKI and for PS-AKISens were 2.15 (2.09-2.21) and 1.28 (1.24-1.32) for ICU use and 4.58 (4.41-4.75) and 1.79 (1.70-1.89) for in-hospital mortality during index hospitalization. For outcomes during 30 days post-discharge, aORs for PS-AKI versus NPS-AKI were 1.07 (1.02-1.11) for readmissions, 1.33 (1.18-1.49) for in-hospital mortality, 15.66 (13.87-17.67) for dialysis, and 6.80 (5.84-7.93) for new dialysis. Despite higher mortality among ICU patients, aORs for outcomes during index and 30 days post-discharge were similar for ICU and non-ICU patients. CONCLUSION: In and out of the ICU, PS-AKI frequently affected inpatients with stage 2 or 3 AKI and was independently associated with worse clinical outcomes during index hospitalization and during 30 days post-discharge. These results suggest that interventions to prevent persistence of severe AKI may reduce adverse clinical outcomes among patients with stage 2 or 3 AKI in or out of the ICU.