title: Hospitalization for achalasia in the United States 1997-2006.
abstract: OBJECTIVE
  The Nationwide Inpatient Sample (NIS) of the Healthcare Cost and Utilization Project (HCUP) was used to study the demographic characteristics of achalasia patients.
  
  
  METHODS
  HCUP data from 1997 to 2006 were stratified by categories pertaining to patient demographics, such as age, sex, race, income, residence in metropolitan area, and region of the United States, as well as categories pertaining to hospital characteristics, such teaching status, location, and bed size. The distributions of inpatients among different categories were compared between achalasia and all other diagnoses, using odds ratios and their 95% confidence intervals for comparison.
  
  
  RESULTS
  The annual hospitalization rates of achalasia revealed a clear-cut age-dependent rise between the youngest age group less than 18 years old (0.25/100,000) and the oldest age group over 85 years old (37.35/100,000). Between 1997 and 2007, the rates of hospitalization remained largely unchanged for all age groups alike. Achalasia was equally distributed among men and women and among various ethnic groups. Compared with other diagnoses, achalasia was more frequent among hospitalized patients from zip codes associated with a higher average income (1.26, 1.23-1.29), living in metropolitan areas (1.12, 1.09-1.15), and living in the northeast region of the United States (1.27, 1.25-1.30). Achalasia patients were mostly seen in large hospitals (1.22, 1.19-1.26), teaching hospitals (1.73, 1.70-1.76), and hospitals located in metropolitan areas (1.15, 1.14-1.15).
  
  
  CONCLUSIONS
  With exception of its striking age-dependence, the epidemiology of achalasia does not reveal any clues about its yet unsolved etiology.
authors.affiliation: Portland VA Medical Center, Oregon Health & Science University, P3-GI, 3710 SW US Veterans Hospital Road, Portland, OR 97239, USA. sonnenbe@ohsu.edu
authors.forename: Amnon
authors.initials: A
authors.lastname: Sonnenberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004931:Esophageal Achalasia / Q000453:epidemiology*; D005260:Female; D005843:Geography; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D012189:Retrospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult