A european-wide study on the role of streptococcus pneumoniae in community-acquired pneumonia among adults: A meta-analysis

OBJECTIVES: Community-acquired pneumococcal pneumonia is an important cause of hospitalization and death among adults, but figures on the prevalence of Streptococcus pneumoniae largely vary. We aimed to identify the prevalence of Streptococcus pneumoniae by systematically reviewing all available etiological studies of adult patients with community-acquired pneumonia (CAP) over the period January 1990- November 2011 across European countries. METHODS: Two reviewers conducted a systematic literature search using PubMed of English-language articles on the prevalence of adult CAP caused by S. Pneumoniae and manually reviewed the article bibliographies. A mixed-effects meta-regression model was developed and populated with 24,236 patients obtained from 79 articles that met in- and exclusion criteria. The meta-regression was adjusted for country and region characteristics as well as other possible independent covariates. RESULTS: The findings from the mixed-effects meta-regression model indicate that the observed prevalence of S. pneumoniae in CAP significantly differs between European regions even after adjusting for various covariates including patient characteristics, diagnostic tests, antibiotic resistance and health-care setting. Performing a diagnostic PCR assay increased the probability of detecting S. pneumoniae substantially, compared to all other diagnostic tests included. Furthermore, S. pneumoniae was more likely to be confirmed as the cause of a CAP in cases treated in the ICU as compared to those treated in the hospital or in the community. CONCLUSIONS: This study provides estimates of the prevalence of S. Pneumoniae in CAP, independent of study design, or other risk factors, which could be used for predictions of the health and economic impact of adult pneumococcal vaccination.