Prediction of patient outcome from Acinetobacter baumannii bacteremia with Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) II scores

Abstract

Objective: Acinetobacter baumannii is an important nosocomial pathogen associated with a high mortality rate. However, no objective and quantitative severity scores are available for the severity stratification. We aimed to assess the effectiveness of SOFA and APACHE II scores calculated at the onset of bacteremia in predicting the mortality of patients with A. baumannii bacteraemia.

Patients and methods: A total of 110 patients with A. baumannii bacteremia were included in this retrospective study during the 40-month study period. Information including clinical and laboratory data was collected.

Results: Multivariate analysis showed that both SOFA and APACHE II scores were independent outcome predictors after adjustment for other parameters. Goodness-of-fit was good for SOFA and APACHE II, and both models displayed excellent AUROCs (SOFA: 0.83 ± 0.06, APACHE II: 0.82 ± 0.08 in predicting 14-day mortality; SOFA: 0.85 ± 0.04, APACHE II: 0.81 ± 0.04 in predicting in-hospital mortality). There was no significant difference in the predictions of the two scoring systems, and the scores were highly correlated (r(2)=0.724, p <0.001). We found that SOFA >8, APACHE II >29 and SOFA >7, APACHE II >23 are associated with significantly higher 14-day and in-hospital mortality rates, respectively.

Conclusion: SOFA and APACHE II scores assessed at the onset of bacteremia are reliable risk stratifying tools in predicting 14-day and in-hospital mortality in A. baumannii bacteremia. For ease of calculation, the use of SOFA rather than APACHE II score to predict mortality of A. baumannii bacteremia might have clinical application.