title: Increased risk of pneumonia following pyogenic liver abscess: a nationwide population-based study.
abstract: OBJECTIVE
  This nationwide study aimed to estimate the risk of pneumonia during a 90-day period following diagnosis with pyogenic liver abscess (PLA) compared to individuals who did not suffer PLA.
  
  
  METHODS
  We investigated the incidence of pneumonia during the 90 days after diagnosis of PLA among 12 868 patients who received medical services for this condition, and compared it to that of 64 340 controls who received medical services for other medical conditions.
  
  
  RESULTS
  We found that the incidence rates of pneumonia were 9.59 and 1.87 per 10 000 person-days in patients with and without PLA, respectively. Stratified Cox proportional hazard regressions found that the hazard ratio for pneumonia among patients with PLA was 5.28 times higher than that of patients without PLA after adjusting for potential confounding factors. We further found Klebsiella pneumoniae to be the causative organism in 84.9% of the cases, but in only 11.7% of the comparison group.
  
  
  CONCLUSIONS
  Our study suggests an increased risk of pneumonia among individuals who have suffered a PLA.
authors.affiliation: Division of Urology, Department of Surgery, Far Eastern Memorial Hospital, Ban Ciao, New Taipei City, Taiwan.
authors.forename: Shiu-Dong
authors.initials: SD
authors.lastname: Chung
authors.forename: Ming-Chieh
authors.initials: MC
authors.lastname: Tsai
authors.forename: Herng-Ching
authors.initials: HC
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D046290:Liver Abscess, Pyogenic / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality; D011159:Population Surveillance; D011379:Prognosis; D016016:Proportional Hazards Models; D012306:Risk; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult