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Crowded emergency rooms are dangerous to our health: ICES study


Long Emergency Department (ED) waiting times are a widespread problem and known to be associated with delays in care and poor outcomes for sick patients. In the first study of its kind, researchers at the Institute for Clinical Evaluative Sciences (ICES) found that ED waiting times may pose a safety risk to the majority of ED patients—those who are seen and sent home.

“Patient safety initiatives have focused on reducing delays for time-sensitive treatments in acutely ill patients and on reducing patients who are leaving without being seen, thought to represent high-risk groups. Yet the vast majority of ED patients are seen by a physician and discharged, and little is known about the safety implications of crowding for these patients,” says Dr. Astrid Guttmann, senior scientist at ICES and a paediatrician at the Hospital for Sick Children. “Although overall rates of mortality are low (0.027% in low acuity/risk patients and 0.125% in high acuity patients), there is a relative increase in mortality associated with increased waiting times.”

The population-based study of non-admitted ED patients in Ontario between 2003 and 2008 found that:

  • Among the 14,551,553 visits, almost 2 per cent were associated with mortality or a need for readmission in the seven days following the first ED visit;
  • Patients who were seen in shifts during which waiting times were longer were more likely to suffer an adverse event;
  • For high acuity patients, the risk of death was 79 per cent higher and for admission 95 per cent higher for shifts with a length of stay of 6 or more hours compared with those of 1 hour;
  • Even for low acuity, less sick patients, the relative increase in risk of death was 71 per cent higher and for admission 66 per cent higher for shifts with length of stay of more than 6 hours;
  • Patients who left the ED without being seen did not have a higher risk of death or need for admission compared with patients who were seen by a physician and discharged.

“There was a consistent pattern of risk that increased with every hour more of the overall length of stay of all similar patients on a shift. Reducing ED waiting times needs to remain a priority. A focus on reducing left-without-being-seen rates may be less important,” says Guttmann.

Author Block: A. Guttmann, M. J. Schull, M. J. Vermeulen, T. A. Stukel.

The study “Association between waiting times and short term mortality and hospital admission after departure from the emergency department: population-based cohort study from Ontario, Canada” in is the June 1, 2011 issue of BMJ.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


Read the Journal Article