Risk factors and outcomes of inadequate empirical antibiotic therapy in ventilator-associated pneumonia: a systematic review and meta-analysis

Objectives: Inadequate empirical antibiotic therapy for ventilator-associated pneumonia (VAP) is defined as at least one bacterial isolate not covered by initial antibiotics, or when the bacteria were resistant to all empiric antibiotics. The aim of our study is to identify the associated risk factors and outcomes of inadequately treated VAP in critically ill adults. Methods: PubMed, Embase, and Google Scholar databases were systematically searched until March 2024. Any observational study reporting on inadequate antibiotic therapy of adult patients (≥18 years) admitted to the intensive care unit (ICU) with a diagnosis of VAP was included in the analysis. The risk factors studied in this meta-analysis were isolation of multi-drug resistant (MDR) bacteria, prior use of antibiotics, admission in surgical units, polymicrobial infection, and late-onset VAP. Likewise, outcomes like in-hospital mortality, length of stay in the ICU and hospital, and duration of intubation were also studied. Results: Isolation of MDR bacteria from the patient significantly increased the risk of inadequate empirical antibiotic treatment (OR = 2.50, 95% C.I. = 1.57-3.97, P < 0.016). Prior use of antibiotics, admission in surgical units, polymicrobial infection, and late-onset VAP were not associated with the inadequate treatment. Likewise, inadequately treated VAP had significantly higher in-hospital mortality (RR = 1.66, 95% C.I. = 1.23-2.23, P < 0.001) and intubation duration (HG = 0.31, 95% C.I. = 0.03-0.59, P = 0.03) as compared to patients who received adequate treatment. Conclusions: VAP caused by MDR pathogens were highly likely to receive inadequate empirical antibiotic therapy. The mortality rate and intubation duration were significantly longer in inadequately treated VAP as compared to adequately treated VAP.