Influence of Appropriate Empirical Antibiotic Treatment on the Prognosis of ICU Patients with HAP Caused by Carbapenem-Resistant Gram-Negative Bacteria

Purpose: In patients with carbapenem-resistant Gram-negative bacteria (CRGNB) infection, the impact of appropriate empirical antibiotic treatment (AEAT) initialized before culture results were available remains controversial. We aimed to investigate the effect of AEAT on the prognosis of critically ill patients with hospital-acquired pneumonia (HAP) caused by CRGNB. Patients and Methods: Patients with CRGNB-infected HAP and received empirical antibiotic treatment (EAT) for at least 3 days in the intensive care unit (ICU) of a tertiary teaching hospital in China from February 2017 to September 2021 were included in the retrospective cohort study. Patients were categorized into AEAT and inappropriate empirical antibiotic treatment (IEAT) groups based on whether they received EAT covering CRGNB. The associations of AEAT with ICU and 28-day mortality were assessed using multivariable logistic regression model. Results: A total of 94 patients were enrolled, including 29 patients in AEAT group and 65 patients in IEAT group. Patients in AEAT group had a higher Sequential Organ Failure Assessment (SOFA) score (P = 0.003), levels of procalcitonin (PCT) (P = 0.001), and lactic acid (LAC) (P = 0.026); while patients in the IEAT group had a higher platelet count (PLT) (P = 0.001). There was no significant difference in the length of ICU stay between the two groups (P = 0.051). Compared with IEAT, AEAT was associated with an increased risk of 28-day mortality in the univariable logistic regression model (OR: 2.618, 95% CI: 1.063–6.448). However, after adjusted for SOFA score, PLT, PCT, and LAC level, the association between AEAT and 28-day mortality diminished (OR: 1.028, 95% CI: 0.353–2.996). AEAT showed no significant association with ICU mortality in neither univariable (OR: 1.167, 95% CI: 0.433– 3.142) nor multivariable (OR: 0.357, 95% CI: 0.097–1.320) models. Conclusion: AEAT showed no significant influence on ICU or 28-day mortality in critically ill patients with HAP caused by CRGNB infection.