Factors influencing mortality in hospital-acquired pneumonia caused by Gram-negative bacteria in China

Abstract

Background: Hospital-acquired pneumonia (HAP) remains an important cause of morbidity and mortality despite advances in antimicrobial therapy. The emergence of Gram-negative bacteria (GNB) is of major concern. The objective of this study was to describe the epidemiology, microbiology, and predictors of infection-related 30-day mortality in HAP with GNB.

Methods: We performed a retrospective, single-center analysis of HAP patients with GNB occurring from January 2014 and December 2017. Univariate and multivariate analyses were performed to identify the risk factors for mortality.

Results: During the observational period, there were 1472 cases of HAP; 314 cases were bacterial culture-positive, 269 cases were caused by GNB, with a predominance of Acinetobacter baumannii and Pseudomonas aeruginosa. The mortality related to GNB was 14.5% (39 deaths).In the multivariate logistic regression analysis, the risk factors for mortality were age >70 years, intensive care unit (ICU) admission, blood lymphocyte count < 0.8 × 10⁹/L, multidrug-resistant Gram-negative bacteria(MDR-GNB) infection, and elevation of blood urea nitrogen(BUN) level. We identified these factors as significant predictors of GNB related mortality; the area under the receiver operating characteristic (ROC) curves was 0.836.

Conclusion: The results provided can help clinicians in identifying individuals who are at risk of infection-related 30-day mortality in HAP with GNB.

Keywords: Gram-negative bacteria; Hospital-acquired pneumonia; Mortality; Predictors.