Epidemiological characteristics of and risk factors for patients with postoperative acute kidney injury: a multicenter prospective study in 30 Chinese intensive care units.

BACKGROUND: Although there were studies to investigate the risk factors for acute kidney injury (AKI) after surgery, most of them focused on one specific type of surgeries. The risk factors for postoperative AKI in patients undergoing all surgeries in intensive care units (ICU) have not been reported.

METHODS: Data from 1731 patients undergoing surgery in 30 ICUs of 28 tertiary hospitals in Beijing from March to August 2012 were prospectively collected. AKI was defined and staged by the KDIGO criteria. Multivariate logistic regression analysis was performed to assess independent risk factors for postoperative AKI.

RESULTS: Postoperative AKI occurred in 44.8% of patients (stage 1 54.8%; stage 2 21.9%, stage 3 23.3%). Cardiovascular surgery was identified as an independent factor for postoperative AKI as well as emergency surgery [odds ratio (OR) 1.403], nephrotoxic drugs (OR 1.303), APACHE II score (OR 1.055), SOFA score (OR 1.115), duration for positive fluid balance (OR 1.165), use of diuretics (OR 2.293), sepsis (OR 1.501), and CKD (OR 4.517). AKI stage 3 versus stages 1-2 was associated with higher mortality in ICU, hospital, and 28-day follow-up after cardiovascular, abdominal, limb, and chest surgeries, while this was not observed after neurosurgery or other surgeries.

CONCLUSION: Risk factors for AKI in ICU patients after different types of surgery were identified. This might be the first step to reduce the high incidence of AKI after surgery. The presence of AKI in ICU patients was associated with higher mortality after most types of surgery, but not after neurosurgery.

TRIAL REGISTRATION: ChiCTR-ONC-11001875.