Prior pneumococcal vaccination is associated with reduced death, complications, and length of stay among hospitalized adults with community-acquired pneumonia

Abstract

Background: Vaccination with pneumococcal polysaccharide reduces the incidence of bacteremic pneumococcal disease in adults. We investigated the impact of prior pneumococcal vaccination on in-hospital mortality and the probability of respiratory failure among hospitalized adults with community-acquired pneumonia.

Methods: Consecutive individuals hospitalized with community-acquired pneumonia (diagnosed by International Classification of Diseases, Ninth Revision, Clinical Modification codes 480.0-487.0) at 109 community and teaching hospitals in the United States were identified using the Quality and Resource Management System, a database constructed by Tenet HealthCare to improve the quality of patient care. Vaccination status, comorbidities, and outcomes were abstracted by case managers concurrently with patient care. Associations between vaccination, survival, and respiratory failure were defined using multivariable logistic regression models.

Results: Of 62,918 adults hospitalized with community-acquired pneumonia between 1999 and 2003, 7390 (12%) had a record of prior pneumococcal vaccination. Vaccine recipients were less likely to die of any cause during hospitalization than were individuals with no record of vaccination (adjusted odds ratio [OR], 0.50; 95% confidence interval [CI], 0.43-0.59), even after adjustment for the presence of comorbid illnesses, age, smoking, and influenza vaccination and under varying assumptions about missing vaccination data. Vaccination also lowered the risk of respiratory failure (adjusted OR, 0.67; 95% CI, 0.59-0.76) and other complications and reduced median length of stay by 2 days, compared with nonvaccination (P<.001).

Conclusions: Prior vaccination against pneumococcus is associated with improved survival, decreased chance of respiratory failure or other complications, and decreased length of stay among hospitalized patients with community-acquired pneumonia. These observations reinforce current efforts to improve compliance with existing pneumococcal vaccination recommendations for adults.