Outcomes of acute kidney injury depend on initial clinical features: A national French cohort study

Abstract

Background. Acute kidney injury (AKI) is a common condition that is associated with poor short- and long-term outcomes. The aim of this nationwide cohort study was to profile the long-term outcome of patients admitted for AKI in France. Methods. Based on the comprehensive French hospital discharge database, all hospitalizations for an AKI episode were categorized in four groups according to the presence of at least one dialysis session [renal replacement therapy (RRT)] and according to the coding of AKI as the principal or associated diagnosis (PRINC_DIAG or ASS_DIAG). Results. In this nationwide cohort of 989 974 patients (median age 77 years) hospitalized with AKI during the 2009–16 period, 422 739 (43%) patients died (235 572 during the first hospitalization) and 40 015 (4%) patients reached end-stage renal disease (ESRD) (5962 during first hospitalization) up to 31 December 2016. Patients without RRT and discharged from hospital had a cumulative incidence of ESRD that ranged from 5.3% (5.2–5.4) in the ASS_DIAG group to 28.7% (27.9–29.5) in the RRT-PRINC_DIAG group at 60 months. The cumulative incidence of death ranged from 31.0% (30.2–32.2) in the RRT-ASS_DIAG group to 45.5% (45.3–45.7) in the ASS_DIAG group. Initial clinical features were associated with outcome independent of comorbidities and age. Conclusions. The death penalty of AKI is abysmal and AKI was an important predisposing factor to chronic ESRD. Our study strengthens the current recommendations for long-term follow-up of patients with AKI. The novelty of this study is to propose a clinical classification of AKI episodes that is easy to detect in administrative medical databases and that is strongly associated with immediate and long-term outcomes.