title: The outcome of community-acquired pneumonia in patients with chronic lung disease: a case-control study.
abstract: BACKGROUND
  The impact of chronic lung diseases on outcome in community-acquired pneumonia (CAP) is not well established. We aimed to investigate the outcome of adult CAP-patients with underlying chronic obstructive pulmonary disease (COPD), asthma or interstitial lung disease (ILD) in a case-control study.
  
  
  METHODS
  We used a nationwide database including all hospitalisations in Switzerland from 2002 to 2010. Endpoints were the incidence of lung abscess, parapneumonic pleural effusion, empyema, acute respiratory distress syndrome, in-hospital mortality and length of stay.
  
  
  RESULTS
  We found less disease-related complications of CAP in COPD (n = 17,075) and asthma (n = 2700) patients compared with their controls. This difference was mainly related to a lower incidence of pleural effusion (COPD: 4.3% vs 4.9%, p = 0.011; asthma: 3.4% vs 5.2%, p <0.001). In-hospital mortality was lower in the COPD and - much more pronounced - asthma cohorts (COPD: 5.8% vs 6.7%, p <0.001; asthma: 1.4% vs 4.8%, p <0.001). For ILD (n = 916), the complication rate was similar as compared to the control group, whereas in-hospital mortality was markedly higher (16.3% vs 6.8%, p <0.001).
  
  
  CONCLUSIONS
  These rather unexpected results should be viewed as hypothesis generating, with various possible explanations for our findings. These include the possible influence of inhaled corticosteroid therapy, a possibly higher awareness of general practitioners and hospital physicians while treating patients with chronic lung diseases, a different infective agent spectrum or a different immune response.
authors.affiliation: Clinic for Pulmonology and Sleep Medicine, Kantonsspital, St. Gallen, Switzerland.
authors.forename: Frank
authors.initials: F
authors.lastname: Dusemund
authors.affiliation: Clinic for Cardiology, Kantonsspital, St. Gallen, Switzerland.
authors.forename: Joannis
authors.initials: J
authors.lastname: Chronis
authors.affiliation: Clinic for Pulmonology and Sleep Medicine, Kantonsspital, St. Gallen, Switzerland.
authors.forename: Florent
authors.initials: F
authors.lastname: Baty
authors.affiliation: Clinic for Infectious Diseases and Hospital Epidemiology, Kantonsspital, St. Gallen, Switzerland.
authors.forename: Werner Christian
authors.initials: WC
authors.lastname: Albrich
authors.affiliation: Clinic for Pulmonology and Sleep Medicine, Kantonsspital, St. Gallen, Switzerland.
authors.forename: Martin Hugo
authors.initials: MH
authors.lastname: Brutsche
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000150:complications / Q000401:mortality; D016022:Case-Control Studies; D017714:Community-Acquired Infections / Q000150:complications / Q000401:mortality; D004653:Empyema / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D007902:Length of Stay; D008169:Lung Abscess / Q000453:epidemiology / Q000209:etiology; D008171:Lung Diseases / Q000150:complications* / Q000401:mortality; D017563:Lung Diseases, Interstitial / Q000150:complications / Q000401:mortality; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000453:epidemiology / Q000209:etiology; D011014:Pneumonia / Q000150:complications* / Q000401:mortality; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000401:mortality; D012128:Respiratory Distress Syndrome / Q000453:epidemiology / Q000209:etiology; D012189:Retrospective Studies; D013557:Switzerland / Q000453:epidemiology; D016896:Treatment Outcome