Association of antibiotic duration and all-cause mortality in a prospective study of patients with ventilator-associated pneumonia in a tertiary-level critical care unit in Southern India.

Objectives: To estimate all-cause mortality in ventilator-associated pneumonia (VAP) and determine whether antibiotic duration beyond 8 days is associated with reduction in all-cause mortality in patients admitted with VAP in the intensive care unit.

Design: A prospective cohort study of patients diagnosed with VAP based on the National Healthcare Safety Network definition and clinical criteria.

Setting: Single tertiary care hospital in Southern India.

Participants: 100 consecutive adult patients diagnosed with VAP were followed up for 28 days postdiagnosis or until discharge.

Outcome Measures: The incidence of mortality at 28 days postdiagnosis was measured. Tests for association and predictors of mortality were determined using χ test and multivariate Cox regression analysis. Secondary outcomes included baseline clinical parameters such as age, underlying comorbidities as well as measuring total length of stay, number of ventilator-free days and antibiotic-free days.

Results: The overall case fatality rate due to VAP was 46%. There was no statistically significant difference in mortality rates between those receiving shorter antibiotic duration (5-8 days) and those on longer therapy. Among those who survived until day 9, the observed risk difference was 15.1% between both groups, with an HR of 1.057 (95% CI 0.26 to 4.28). In 70.4% of isolates, non-fermenting Gram-negative bacilli were identified, of which the most common pathogen isolated was (62%).

Conclusion: In this hospital-based cohort study, there is insufficient evidence to suggest that prolonging antibiotic duration beyond 8 days in patients with VAP improves survival.