Is ventilator-associated pneumonia an independent risk factor for death?

Background: Ventilator-associated pneumonia (VAP) has been implicitly accus ed of increasing mortality. However, it is not certain that pneumonia is re sponsible for death or whether fatal outcome is caused by other risk factor s for death that exist before the onset of pneumonia. The aim of this study was to evaluate the attributable mortality caused by VAP by performing a m atched-paired, case-control study between patients who died and patients wh o were discharged from the intensive care unit after more than 48 h of mech anical ventilation. Methods: During the study period, 135 consecutive deaths were included in t he case group. Case-control matching criteria were as follows: (1) diagnosi s on admission that corresponded to 1 of 11 predefined diagnostic groups; ( 2) age difference within 10 yr; (3) sex; (4) admission within 1 yr; (5) APA CHE II score within 7 points; (6) ventilation of control patients for at le ast as long as the cases. Precise clinical, radiologic, and microbiologic d efinitions were used to identify VAP. Results: Analysis was performed on 108 pairs that were matched with 91% of success. There mere 39 patients (36.1%) who developed VAP in each group. Mu ltivariate analysis showed that renal failure, bone marrow failure, and tre atment with corticosteroids but not VAP were independent risk factors for d eath. There was no difference observed between cases and controls concernin g the clinical and microbiologic diagnostic criteria for pneumonia. Conclusion: Ventilator-associated pneumonia does not appear to be an indepe ndent risk factor for death.