Antibiotic therapy prior to hospital admission is associated with reduced septic shock and need for mechanical ventilation in patients with community-acquired pneumonia.

A subgroup of patients admitted to the hospital with a diagnosis of community-acquired pneumonia (CAP) have received antibiotic therapy prior to admission for the current episode of pneumonia. The objective of this study was to assess the clinical course of patients receiving antibiotics prior to admission, compared to patients not previously treated. An observational cohort of 3364 CAP patients consecutively admitted to our hospital, and prospectively included, were studied. We collected clinical, microbiological and biochemical parameters, focusing on recent antibiotics received prior to admission. 610 (18%) patients received antibiotics prior to hospital admission for the current CAP episode. Patients with previous antibiotic use developed septic shock less frequently (4% vs. 7%, p = 0.007) and required invasive ventilation less often (3% vs. 6%, p = 0.002). After adjustment by different covariate factors and propensity score, antibiotic therapy was still independently associated with a lower incidence of septic shock at admission (OR 0.54 [95% CI 0.31-0.95], p = 0.03) and less need for invasive ventilation (OR 0.38 [95% CI 0.16-0.91], p = 0.03). In this cohort, recent use of antibiotics before hospital admission in CAP seems to be associated with a lower incidence of septic shock on admission and a lower need for invasive ventilation.