Long-Term Mortality among Hospitalized Non-ICU Patients with Acute Kidney Injury Referred to Nephrology.

BACKGROUND: Epidemiological studies of acute kidney injury (AKI) have focused on patients admitted to intensive care units (ICUs), and several have studied hospitalized non-ICU patients, but analysis of patients referred to Nephrology is sparse. We analyzed factors associated with short- and long-term morbimortality among hospitalized non-ICU patients with AKI who were referred to Nephrology.

METHODS: A retrospective study with data prospectively collected from 170 non-ICU patients, with referral to the Nephrology Unit, recruited over a 4-year period, was performed. AKI was classified according to the criteria based on risk, injury, failure, loss of kidney function and end-stage kidney disease (RIFLE). Risk factors that could influence prognosis of AKI and long-term mortality were analyzed at admission. Early on, 1- and 10-year mortalities were correlated with AKI RIFLE class, clinical and demographic characteristics.

RESULTS: Most patients were >65 years, with multiple comorbidities and frequent drug intake history. Median Charlson score was 6. Twenty-five percent of patients with previously unknown chronic kidney disease (CKD) were diagnosed with CKD during the study. Dialysis was required in 13.5% of patients. Hospital deaths were 22.4% and significantly associated with older age, RIFLE class L, higher peak serum creatinine, oliguria and decreased serum albumin levels. One-year (38.8%) and 10-year (68.8%) mortalities were significantly associated with age, prior cardiovascular disease, prior CKD and RIFLE class L. According to the Cox proportional hazard model, age, prior CKD and RIFLE class L were independent risk factors of death at 1 and 10 years.

CONCLUSIONS: AKI in hospitalized non-ICU patients is associated with high early and late mortality. This study increases our understanding of AKI among this specific population and can improve their management.