Characteristics and outcomes in community-acquired versus hospital-acquired acute kidney injury

Aim Relatively little is known about the prevalence of acute kidney injury developing outside a hospital setting (CA-AKI) or the impact of CA-AKI on short-term or long-term clinical outcomes. The objective of this study was to compare the prevalence, causes, severity and outcomes of patients with CA-AKI and hospital-acquired (HA)-AKI. Methods A retrospective cohort study of patients with AKI identified by ICD-9 code at a single VA (Veterans Affairs) hospital from September 1999 to May 2007 was performed. AKI was verified by applying the RIFLE criteria, and patients were categorized as CA-AKI if RIFLE criteria were met at admission. Demographic, clinical, and outcome variables were extracted by chart review. Results Four hundred twenty-two patients met inclusion criteria, of which 335 (79.4%) developed CA-AKI. Patients with CA-AKI were more likely to have volume depletion as the aetiology, had fewer chronic illnesses and hospital complications, had a shorter length of stay, and had a reduced mortality, compared with HA-AKI. Distribution among the three RIFLE classes did not differ between groups, and recovery of renal function was incomplete in both groups. Conclusion We conclude that CA-AKI is a common cause of AKI that is as severe as that seen in HA-AKI. CA-AKI has a significant impact on length of hospital stay, mortality, and the development and/or progression of chronic kidney disease. Strategies to limit the risk of CA-AKI are likely to have a significant impact on healthcare costs and patient care.