title: Incidence and risk factors of recurrent acute lung injury.
abstract: OBJECTIVE
  To determine risk factors for development of recurrent acute lung injury.
  
  
  METHODS
  A population-based case-control study.
  
  
  METHODS
  The study was conducted in Olmsted County, MN, from 1999 to 2008.
  
  
  METHODS
  Using a validated electronic screening protocol, investigators identified intensive care patients with acute hypoxemia and bilateral pulmonary infiltrates.
  
  
  METHODS
  None.
  
  
  RESULTS
  The presence of acute lung injury was independently confirmed according to American-European Consensus Conference criteria. Recurrent acute lung injury cases were subsequently matched (1:1:1) with two controls (single acute lung injury and no acute lung injury) on age, gender, duration of follow-up, and predisposing conditions. Risk factors evaluated included gastroesophageal reflux disease, alcohol consumption, smoking, chronic opioid use, and transfusions. We identified 917 patients with acute lung injury, 19 of which developed a second episode, yielding a frequency of 2.02 (95% confidence interval 1.10-2.93) per 100,000 person years. The median time to development of the second episode was 264 days (interquartile range 80-460 days), with a mortality of 47% during the episode. The history of gastroesophageal reflux disease was highly prevalent in patients who developed recurrent acute lung injury: 15 of 19 patients (79%) compared to 5 of 19 (26%) matches with a single episode of acute lung injury (p = .006) and 8 of 19 (42%) matches without acute lung injury (p = .016). Other exposures were similar between the cases and the two matched controls.
  
  
  CONCLUSIONS
  Recurrent acute lung injury is not a rare phenomenon in the intensive care unit and may continue to increase with improvements in survival following acute lung injury. Gastroesophageal reflux disease was identified as an important risk factor for recurrent acute lung injury and may suggest an important role of gastric aspiration in the development of this syndrome.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Mayo Epidemiology and Translational Research in Intensive Care, Mayo Clinic, Rochester, MN, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bice
authors.forename: Guangxi
authors.initials: G
authors.lastname: Li
authors.forename: Michael
authors.initials: M
authors.lastname: Malinchoc
authors.forename: Augustine S
authors.initials: AS
authors.lastname: Lee
authors.forename: Ognjen
authors.initials: O
authors.lastname: Gajic
mesh_terms: D055371:Acute Lung Injury / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015897:Comorbidity; D016001:Confidence Intervals; D003422:Critical Care / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000453:epidemiology*; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012008:Recurrence; D012016:Reference Values; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D015996:Survival Rate