Timing and Degree of Acute Kidney Injury in Patients Requiring Non-Surgical Intensive Care

The degree and timing of acute kidney injury (AKI) on admission and during hospitalization in patients requiring non-surgical intensive care remain unclear.Methods and Results: In this study, 3,758 patients requiring intensive care were analyzed retrospectively. AKI was defined based on the ratio of serum creatinine concentrations recorded at each time point (i.e., on admission and during the first 5 days in the intensive care unit and during hospitalization) to those measured at baseline. Patients were grouped by combining AKI severity (RIFLE class) and timing (i.e., from admission to 5 days [A-5D]; from 5 days to hospital discharge [5D-HD]) as follows: No-AKI; New-AKI (no AKI to Class R [risk; ≥1.5-fold increase in serum creatinine], I [injury; ≥2.0-fold increase in serum creatinine], and F [failure; ≥3.0-fold increase in serum creatinine or receiving dialysis during hospitalization]); Stable-AKI (Class R to R; Class I to I); and Worsening-AKI (Class R to I or F; Class I to F). Multivariate logistic regression analysis indicated that 730-day mortality was independently associated with Class R, I, and F on admission; Class I and F during the 5D-H period; and New-AKI and Worsening-AKI during A-5D and 5D-HD.AKI on admission, even Class R, was associated with a poor prognosis. An increase in RIFLE class during hospitalization was identified as an important factor for poor prognosis in patients requiring intensive care.