Acute kidney injury in an infectious disease intensive care unit - an assessment of prognostic factors

BACKGROUND: Acute kidney injury (AKI) is a common complication in many infectious diseases. There are few studies to investigate risk factors for death in infectious diseases-associated AKI. METHODS: This is a retrospective study including all patients with acute kidney injury (AKI) admitted to an infectious diseases intensive care unit (ICU) in Brazil between October 2003 and September 2006. RESULTS: A total of 722 patients were admitted to the infectious disease ICU in the study period. AKI occurred in 147 cases (17.7%). The mean age was 45 +/- 5.6 years, and 77% were male. The mean length of hospital stay was 11.5 +/- 10.3 days. The main causes of ICU hospitalization were acquired immunodeficiency syndrome (AIDS)-related diseases (28 .6%), pneumonia 13%), leptospirosis (11.6%), meningitis (8.2%), disseminated histoplasmosis (6.8%) and tetanus (5.4%). The main cause of AKI was sepsis (41.5%). Patients were classified according to RIFLE as "Risk" (5.6%), "Injury" (21.7%) and "Failure" (72.7%). Patients in "Failure" showed a higher mortality (p = 0.007). Multivariate analysis showed that dependent risk factors for death were oliguria (OR = 5.59, P = 0.002), metabolic acidosis (OR = 5.13, P = 0.01), sepsis (OR = 4.79, P = 0.001), hypovolaemia (OR = 4.11, P = 0.01), use of vasoactive drugs (OR = 3.34, P = 0.02), use of mechanical ventilation (OR = 2.94, P = 0.03) and high APACHE II score (OR = 1.14, P = 0.001). CONCLUSION: There are important risk factors for death among critically ill patients with infectious diseases associated with AKI.