Risk factors for mortality in intensive care unit patients with sepsis combined with acute kidney injury after continuous renal replacement therapy: secondary analysis of the data from a multicenter observational study

Abstract

To analyze the risk factors of death in intensive care unit (ICU) patients with sepsis and acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). The data of patients with sepsis complicated with AKI who received CRRT treatment from March 1st to August 31st in 2012 in BAKIT study (a prospective observational study of AKI epidemiology in 30 ICUs of 28 hospitals in Beijing) were re-analyzed. The demographic data, clinical and laboratory data of patients were collected, including gender, age, case source, body mass index (BMI), blood pressure, the length of ICU stay, complications, other organs' function, drug use, CRRT, mechanical ventilation and vasoactive drugs. Acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure score (SOFA) were calculated by the worst value of the index within 24 hours of entry into ICU. The end point of observation was to ICU mortality. All test factors were analyzed by single factor analysis, and then multivariate Logistic regression analysis was carried out for the parameters with statistical significance in single factor analysis. Risk factors affecting CRRT in ICU sepsis patients with AKI were screened. A total of 189 patients were enrolled, 103 of whom died, with a mortality rate of 54.50%. Compared with the survival group, the death group had an older age [years old: 77(67, 83) vs. 58 (39, 73)], a higher proportion of ICU entry due to respiratory diseases (55.40% vs. 38.37%), a higher proportion of complications such as grade IV of cardiac function, hypertension, coronary heart disease, chronic kidney disease (with renal insufficiency; 20.39% vs. 3.49%, 53.40% vs. 34.88%, 40.78% vs.10.47%, 20.39% vs. 9.30%, respectively), a longer the length of ICU stay [days: 8 (5, 19) vs. 13 (7, 22)], a higher APACHE II and SOFA scores (27.53±8.59 vs. 22.73±8.36, 12.22±4.00 vs. 9.51±4.49), a lower mean arterial pressure (MAP) valley value [mmHg (1 mmHg = 0.133 kPa): 65.36±19.52 vs. 71.60±17.92], a higher proportion of invasive mechanical ventilation (80.58% vs. 65.12%), high proportion of CRRT treatment due to hyperkalemia and severe metabolic acidosis (28.16% vs. 9.30%, 63.11% vs. 22.09%), and the time from ICU entry to CRRT initiation was longer [days: 1 (0, 5) vs. 1 (0, 2)], which differences were statistically significant (all P < 0.05). Logistic regression analysis showed that age, APACHE II, SOFA, MAP, grade IV of cardiac function, coronary heart disease and hyperkalemia were risk factors for death in ICU sepsis patients with AKI treated by CRRT. Age, APACHE II, SOFA and grade IV of cardiac function were independent risk factors [age: odds ratio (OR) = 1.054, 95% confidence interval (95%CI) = 1.032-1.077, P < 0.001; APACHE II: OR = 1.061, 95%CI = 1.021-1.102, P = 0.034; SOFA: OR = 1.078, 95%CI = 1.033-1.116, P = 0.042; grade IV of cardiac function: OR = 3.357, 95%CI = 0.884-12.747, P = 0.045]. Age, APACHE II, SOAF and grade IV of cardiac function were independent risk factors for death in ICU sepsis patients with AKI treated with CRRT. Chinese Clinical Trial Registry, ChiCTR-ONC-11001875.