title: Prognostic implications of aspiration pneumonia in patients with community acquired pneumonia: A systematic review with meta-analysis.
abstract: Aspiration pneumonia is thought to be associated with a poor outcome in patients with community acquired pneumonia (CAP). However, there has been no systematic review regarding the impact of aspiration pneumonia on the outcomes in patients with CAP. This review was conducted using the MOOSE guidelines: Patients: patients defined CAP.
  
  
  
  aspiration pneumonia defined as pneumonia in patients who have aspiration risk. Comparison: confirmed pneumonia in patients who were not considered to be at high risk for oral aspiration.
  
  
  
  mortality, hospital readmission or recurrent pneumonia. Three investigators independently identified published cohort studies from PubMed, CENTRAL database, and EMBASE. Nineteen studies were included for this systematic review. Aspiration pneumonia increased in-hospital mortality (relative risk, 3.62; 95% CI, 2.65-4.96; P < 0.001, seven studies) and 30-day mortality (3.57; 2.18-5.86; P < 0.001, five studies). In contrast, aspiration pneumonia was associated with decreased ICU mortality (relative risk, 0.40; 95% CI, 0.26-0.60; P < 0.00001, four studies). Although there are insufficient data to perform a meta-analysis on long-term mortality, recurrent pneumonia, and hospital readmission, the few reported studies suggest that aspiration pneumonia is also associated with these poor outcomes. In conclusion, aspiration pneumonia was associated with both higher in-hospital and 30-day mortality in patients with CAP outside ICU settings.
authors.affiliation: Department of Pediatrics, Virginia Commonwealth University School of Medicine, 1217 East Marshall Street: KMSB, Room 215 Richmond, Virginia 23298, USA.|Respiratory Medicine and Infectious Diseases, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan.|Clinical Research Center of Respiratory Medicine, Tenshindo Hetsugi Hospital, 5956 Nihongi, Nakahetsugi, Oita, 879-7761, Japan.
authors.forename: Kosaku
authors.initials: K
authors.lastname: Komiya
authors.affiliation: Department of Pediatrics, Virginia Commonwealth University School of Medicine, 1217 East Marshall Street: KMSB, Room 215 Richmond, Virginia 23298, USA.
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Rubin
authors.affiliation: Respiratory Medicine and Infectious Diseases, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Kadota
authors.affiliation: Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
authors.affiliation: Department of Pediatrics, Virginia Commonwealth University School of Medicine, 1217 East Marshall Street: KMSB, Room 215 Richmond, Virginia 23298, USA.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Akaba
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, 757 Asahi-machi, Chuo-ku, Niigata, 951-8510, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Moro
authors.affiliation: Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, 757 Asahi-machi, Chuo-ku, Niigata, 951-8510, Japan.
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Aoki
authors.affiliation: Department of Respiratory Medicine/Infectious Disease, Niigata City General Hospital, 463-7 Shumoku, Chuo-ku, Niigata, 950-1197, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Tsukada
authors.affiliation: Department of Respiratory Medicine, University of Occupational and Environmental Health, 1-1 Idaigaoka, Yahatanishi-ku, Kitakyushu, 807-8555, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Noguchi
authors.affiliation: Department of Emergency and Critical Care Medicine, Institute of Biomedical &Health Sciences, Hiroshima University Advanced Emergency and Critical Care Center, Hiroshima University Hospital, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Shime
authors.affiliation: Center for Clinical Epidemiology, St. Luke's Life Science Institute, 10-1 Akashicho, Chuo-ku, Tokyo, 104-0044, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Takahashi
authors.affiliation: Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohno
mesh_terms: D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000401:mortality / Q000473:pathology*; D017052:Hospital Mortality; D006801:Humans; D064887:Observational Studies as Topic; D010359:Patient Readmission; D011015:Pneumonia, Aspiration / Q000401:mortality / Q000473:pathology*; D011379:Prognosis