Acute Kidney Injury After Cardiac Surgery by Complete KDIGO Criteria Predicts Increased Mortality

Acute kidney injury (AKI) occurs frequently after cardiac surgery and is associated with increased mortality. The Kidney Disease: Improving Global Outcomes (KDIGO) criteria for diagnosing AKI include creatinine and urine output values. However, the value of the latter is debated. The authors aimed to evaluate the incidence of AKI after cardiac surgery and the independent association of KDIGO criteria, especially the urine output criterion, and 2.5-year mortality.

Prospective, observational, cohort study.

Single-center study in a university hospital.

The study comprised 638 cardiac surgical patients from September 1, 2011, to June 20, 2012.

None.

Hourly urine output, daily plasma creatinine, risk factors for AKI, and variables for EuroSCORE II were recorded. AKI occurred in 183 (28.7%) patients. Patients with AKI diagnosed using only urine output had higher 2.5-year mortality than did patients without AKI (9/53 [17.0%] v 23/455 [5.1%], p = 0.001). AKI was associated with mortality (hazard ratios [95% confidence intervals]: 3.3 [1.8-6.1] for KDIGO 1; 5.8 [2.7-12.1] for KDIGO 2; and 7.9 [3.5-17.6]) for KDIGO 3. KDIGO stages and AKI diagnosed using urine output were associated with mortality even after adjusting for mortality risk assessed using EuroSCORE II and risk factors for AKI.

AKI diagnosed using only the urine output criterion without fulfilling the creatinine criterion and all stages of AKI were associated with long-term mortality. Preoperatively assessed mortality risk using EuroSCORE II did not predict this AKI-associated mortality.