title: Risk of emergency admission while awaiting elective cholecystectomy.
abstract: BACKGROUND
  There is uncertainty regarding the frequency of adverse events while on a surgical waiting list. We assess the relationship between the duration of wait for cholecystectomy and the risk of emergency admission.
  
  
  METHODS
  We analyzed time to emergency admission in a group of 761 patients who underwent cholecystectomy after being seen in clinic for biliary colic and placed on waiting lists at 2 acute care centres in Ontario, from 1997 to 2000.
  
  
  RESULTS
  Emergency admissions due to worsening symptoms occurred in 51 patients (6.7%) waiting for elective cholecystectomy. The weekly rate of emergency admission was low during the first 19 weeks on the list, but increased almost by a factor of 3 after 20 weeks (rate ratio 2.7; 95% confidence interval 2.0-3.7). Relative to the first 4 weeks on the list, the rate was 1.6 times higher after 20 weeks, 2 times higher after 28 weeks and 7 times higher after 40 weeks.
  
  
  CONCLUSIONS
  The probability that a patient on a waiting list will be admitted for emergency cholecystectomy consistently increases with the duration of wait, particularly after 20 weeks.
mesh_terms: D000328:Adult; D000368:Aged; D002763:Cholecystectomy; D016001:Confidence Intervals; D004630:Emergencies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D012307:Risk Factors; D013997:Time Factors; D014850:Waiting Lists