The study evaluates how outcome varies among critically ill patients with and without acute kidney injury. Data from the Swedish Intensive care register and other Swedish national registers is used to compare how survival and post discharge renal function differ between critically ill patients with and without acute kidney injury.

Background: Acute kidney injury is common amongst intensive care patients and is associated with extremely high mortality and morbidity in terms of increased risk of developing Chronic Kidney Disease (CKD) and End Stage Renal Disease (ESRD). Patients with CKD are at increased risk of cardiovascular, cerebro-vascular disease and long term increased risk of death. Those patients who progress to ESRD have a 20% mortality risk per year in Sweden. Outcome after acute kidney injury in the Swedish critical care population has never previously been described.

Method: This cohort study uses Swedish national healthcare registers to investigate the epidemiology of acute kidney injury. The Swedish Intensive Care Register (SIR) provides the population base, with data extraction between 2005 and 2011. The information obtained is cross-matched by the Swedish board for health and welfare (Social Styrelsen) with other national registries. All data are returned anonymized and individual patients can not be identified in any way. Additionally analysis is performed on a group and not on an individual basis. The key to this data is held by Swedish board for health and welfare. The other national registries include the Swedish Cause of Death Register (Dödsregister), the Swedish renal register (Svensknjurregistret) and the in and out-patients registers (Öppen- slutenvårdsregister) these are used to obtain data on all cause mortality, co-morbidities, Pre and Post ICU CKD and ESRD. Epidemiological methods are used to analyse the data.

Investigators aim to describe outcome in terms of long-term mortality (up to five years) and renal morbidity (incidence of CKD and ESRD) in critically ill patients with and without de novo AKI in Sweden.

Inclusion Criteria:

All first admissions of adult patients registered on the Swedish Intensive Care Register between January 1st 2005 and January 1st 2011.

Exclusion Criteria:

Patients under 18. Subjects with incomplete records. Patients previously diagnosed with Chronic Kidney Disease or End Stage Renal disease.

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The study population was provided by the Swedish Intensive Care register and included patients receiving intensive care treatment between January 2005 and January 2011