title: Acute respiratory distress syndrome: nationwide changes in incidence, treatment and mortality over 23 years.
abstract: BACKGROUND
  The aim of this study was to assess population-based changes in incidence, treatment, and in short- and long-term survival of patients with acute respiratory distress syndrome (ARDS) over 23 years.
  
  
  METHODS
  Analysis of all patients in Iceland who fulfilled the consensus criteria for ARDS in 1988-2010. Demographic variables, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and ventilation parameters were collected from hospital charts.
  
  
  RESULTS
  The age-standardised incidence of ARDS during the study period was 7.2 cases per 100,000 person-years and was increased by 0.2 cases per year (P < 0.001). The most common causes of ARDS were pneumonia (29%) and sepsis (29%). The use of pressure-controlled ventilation became almost dominant from 1993. The peak inspiratory pressure (PIP) has significantly decreased (-0.5 cmH(2) O/year), but the peak end-expiratory pressure (PEEP) has increased (0.1 cmH(2) O/year) during the study period. The hospital mortality decreased by 1% per year (P = 0.03) during the study period, from 50% in 1988-1992 to 33% in 2006-2010. A multivariable logistic regression model revealed that higher age and APACHE II score increased the odds of hospital mortality, while a higher calendar year of diagnosis reduced the odds of mortality. This was unchanged when dominant respiratory treatment, PIP and PEEP were added to the model. The 10-year survival of ARDS survivors was 68% compared with 90% survival of a reference population (P < 0.001).
  
  
  CONCLUSIONS
  The incidence of ARDS has almost doubled, but hospital mortality has decreased during the 23 years of observation. The 10-year survival of ARDS survivors is poor compared with the reference population.
authors.affiliation: Department of Anaesthesia and Intensive Care Medicine, Landspitali University Hospital, Reykjavik, Iceland. gislihs@landspitali.is
authors.forename: M I
authors.initials: MI
authors.lastname: Sigurdsson
authors.forename: K
authors.initials: K
authors.lastname: Sigvaldason
authors.forename: T S
authors.initials: TS
authors.lastname: Gunnarsson
authors.forename: A
authors.initials: A
authors.lastname: Moller
authors.forename: G H
authors.initials: GH
authors.lastname: Sigurdsson
mesh_terms: D018806:APACHE; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003422:Critical Care; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D007223:Infant; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011379:Prognosis; D012128:Respiratory Distress Syndrome / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy*; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000453:epidemiology / Q000209:etiology; D012737:Sex Factors; D013534:Survival; D016019:Survival Analysis; D055815:Young Adult