title: Complications following gastrointestinal bleeding and their impact on outcome and death.
abstract: BACKGROUND
  Bleeding from the upper gastrointestinal tract is one of the most common life-threatening morbidities encountered by gastroenterologists. A mathematical model has been developed to gain insights into how, after an initial event of upper gastrointestinal bleeding, complications can accumulate in individual patients and expose them to an increased risk of death.
  
  
  METHODS
  The occurrence of complications and possible death after gastrointestinal bleeding are simulated using a Markov chain model.
  
  
  RESULTS
  The accumulation of complications in an individual patient is influenced by the length of time a patient remains vulnerable to the probability of developing new complications. The model illustrates how the initial bleeding episode sets the stage for the occurrence of subsequent complications and how each subsequent complication increases in an exponential manner the risk for additional complications. Because of such a pattern, complications tend to cluster in a group of patients who run into an ever-increasing risk of multiple complications. Although the majority of patients go through their initial bleeding episode without ever experiencing any secondary complication, in a subset of patients the initial complication sets in motion a vicious cycle with frequently more than one consecutive complication after the initial gastrointestinal bleed.
  
  
  CONCLUSIONS
  The key to the successful management of a patient with gastrointestinal bleeding is to stop such a vicious cycle as early as possible, as each progression within the cycle renders the probability of additional complications more likely and its reversal more difficult.
authors.affiliation: Portland VA Medical Center, SW US Veterans Hospital Road, Portland, OR 97239, USA. sonnenbe@ohsu.edu
authors.forename: Amnon
authors.initials: A
authors.lastname: Sonnenberg
mesh_terms: D018450:Disease Progression; D016099:Endoscopy, Gastrointestinal; D006471:Gastrointestinal Hemorrhage / Q000150:complications* / Q000401:mortality / Q000628:therapy; D006801:Humans; D008390:Markov Chains; D008954:Models, Biological; D011379:Prognosis; D013997:Time Factors