title: Amoebic liver abscess in USA: a population-based study of incidence, temporal trends and mortality.
abstract: BACKGROUND
  Amoebic liver abscess (ALA) may be associated with significant morbidity and mortality, but nationwide American data is unavailable. Our objective was to describe ALA epidemiology and outcomes in USA from a population-based perspective.
  
  
  METHODS
  Patients hospitalized with ALA between 1993 and 2007 were identified using the Nationwide Inpatient Sample. Patient characteristics, interventions and outcomes including mortality were determined. The annual incidence of ALA and temporal trends were determined using the negative binomial regression models.
  
  
  RESULTS
  Between 1993 and 2007, 848 hospitalizations for ALA, corresponding to ∼4100 hospitalizations nationwide, were identified. The annual incidence was 1.38 per million population with a 2.4% [95% confidence interval (CI) 0-4.8%; P=0.06] average annual decline during this study. Most patients were hospitalized in western (54%) and southern states (27%), and 48% were Hispanic. Males (incidence rate ratio vs. females: 4.53; 95% CI 4.19-4.90) had the highest incidence rates. Percutaneous and surgical drainage was required in 48 and 7% of patients respectively. Although length of stay [median, 6 days; interquartile range (IQR) 4-10] and hospital charges (US$25,345; IQR US$15,030-42, 275) were substantial, in-hospital mortality was rare (0.8%). Females [odds ratio (OR) 6.12; CI 1.39-26.8], patients ≥ 60 years (OR 13.3; 95% CI 2.5-71.5), and those with ≥ 3 comorbidities (OR 5.80; 95% CI 1.30-25.8), particularly malnutrition, had an increased risk of death.
  
  
  CONCLUSIONS
  ALA is rare and the incidence has decreased in USA. Young, Hispanic males in southwestern states are most frequently affected. Mortality caused by ALA is lower than what was reported previously.
authors: Liver Unit, Department of Medicine, Division of Gastroenterology, University of Calgary, Calgary, Alberta, Canada.
authors: Stephen E
authors: SE
authors: Congly
authors: Abdel Aziz M
authors: AA
authors: Shaheen
authors: Liisa
authors: L
authors: Meddings
authors: Gilaad G
authors: GG
authors: Kaplan
authors: Robert P
authors: RP
authors: Myers
mesh_terms: D000328:Adult; D000367:Age Factors; D016009:Chi-Square Distribution; D004322:Drainage / Q000401:mortality; D004813:Epidemiology / Q000639:trends; D005260:Female; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D017722:Hospital Charges; D017052:Hospital Mortality / Q000639:trends; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007902:Length of Stay; D008101:Liver Abscess, Amebic / Q000191:economics / Q000453:epidemiology* / Q000208:ethnology / Q000401:mortality* / Q000628:therapy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012111:Residence Characteristics; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D013396:Suction / Q000401:mortality; D013997:Time Factors; D014481:United States / Q000453:epidemiology