Attributable mortality of ventilator-associated pneumonia: a meta-analysis

OBJECTIVE: To investigate whether ventilator-associated pneumonia (VAP) is a true cause of mortality in the intensive care unit setting. METHODS: We performed a meta-analysis of available data without time restrictions. A conservative random effects model was employed to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Of 968 retrieved reports, 44 studies fulfilled our inclusion criteria. Presence, as opposed to absence, of VAP was associated with higher mortality in the ICU setting (OR 1.96, 95% CI 1.26-3.04). This result persisted when matched case-control studies (OR 1.73, 95% CI 1.23-2.45) or studies in which VAP was microbiologically confirmed in all patients (OR 2.20, 95% CI 1.01-4.81) were evaluated separately. VAP continued to be associated with higher mortality when the impact of immune suppression was controlled. VAP was not associated with higher mortality in the subgroup analysis of studies including patients who received appropriate initial antimicrobial treatment (OR 1.64, 95% CI 0.68-3.96). CONCLUSION: Presence, compared to absence, of VAP seems to be associated with higher mortality in critically ill patients. Appropriateness of initial antimicrobial treatment in such patients may moderate this association.