title: Bacterial aetiology and mortality in COPD patients with CAP: results from the German Competence Network, CAPNETZ.
abstract: Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality, and chronic obstructive pulmonary disease (COPD) is a frequent comorbidity. The bacterial aetiology of CAP-COPD and its possible associations with serum markers and mortality are incompletely understood.
  
  
  
  1) To assess the bacterial aetiology of CAP only and CAP-COPD, and 2) to study the association between bacterial aetiology, empirical antibiotic treatment, serum markers and mortality.
  
  
  
  Of 1288 patients with CAP (57.0% males, age 59.0 years ± 18.5), 262 (20.3%) fulfilled the diagnostic criteria for COPD. Differences between subgroups were investigated using univariate analyses and corrected for multiple comparisons.
  
  
  
  Streptococcus pneumoniae was the most common pathogen (30.8% CAP only vs. 26.0% CAP-COPD, not significant). Haemophilus influenzae was significantly more frequent in CAP-COPD (5.6% CAP only vs. 26.0% CAP-COPD, P < 0.001). The number given adequate empirical antibiotic treatment was comparable (83.3% CAP only vs. 83.6% CAP-COPD, P > 0.05). The CAP-COPD group had worse CURB-65 and partial pressure of arterial oxygen levels than the CAP only group (P < 0.001). Partial pressure of arterial carbon dioxide levels were increased in CAP-COPD patients without pathogen detection (P < 0.001). Short- (P = 0.011) and long-term mortality (P = 0.006) were highest in CAP-COPD without pathogen detection.
  
  
  
  It is important to identify COPD patients with CAP. In particular, those without bacterial pathogen detection have more severe CAP and are at higher risk of dying. Better understanding of the aetiology could contribute to improved management and treatment of CAP in COPD patients.
authors.affiliation: Department of Research and Education, CIRO, Horn, Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
authors.forename: D C W
authors.initials: DC
authors.lastname: Braeken
authors.affiliation: Department of Research and Education, CIRO, Horn, Department of Respiratory Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
authors.forename: F M E
authors.initials: FM
authors.lastname: Franssen
authors.affiliation: Department of Medical Microbiology and Hygiene, University Hospital of Ulm, Ulm, Germany.
authors.forename: H
authors.initials: H
authors.lastname: von Baum
authors.affiliation: Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Ernst von Bergmann Klinikum, Potsdam, CAPNETZ Stiftung, Hannover, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Schütte
authors.affiliation: CAPNETZ Stiftung, Hannover, Center for Diseases and Infection Control, Jena University Hospital, Jena, Germany.
authors.forename: M W
authors.initials: MW
authors.lastname: Pletz
authors.affiliation: CAPNETZ Stiftung, Hannover, Department of Molecular and Clinical Infectious Diseases, University of Lübeck, Lübeck, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Rupp
authors.affiliation: Department of Medical Microbiology, MUMC+, Maastricht, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: Stassen
authors.affiliation: Department of Medical Microbiology, MUMC+, Maastricht, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Mooij
authors.affiliation: Department of Research and Education, CIRO, Horn, CAPNETZ Stiftung, Hannover, Germany.
authors.forename: G G U
authors.initials: GG
authors.lastname: Rohde
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001419:Bacteria / Q000302:isolation & purification; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000401:mortality
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D002245:Carbon Dioxide