Mortality of the users of a hospital emergency department.

OBJECTIVE To ascertain the annual number of users who were discharged home after visits to the emergency department (ED), grouped by age, sex, and number of visits during the calendar year, and to assess whether a higher number of visits to the department predicted a higher mortality. METHODS This was a retrospective cohort study, with follow up of cause specific mortality through a national registry, in the Reykjavik area of Iceland. In total, 19 259 patients who visited the ED during the period 1995-2001 and who were discharged home at the Landspítali University Hospital, Reykjavik, Iceland, were enrolled. The main outcome measures were the standardised mortality ratio, with expected number based on national mortality rates, and hazard ratio calculations using time dependent multivariate regression analysis. RESULTS The annual increase in visits to the ED among the patients discharged home was 7-14% per age group during the period 1995-2001, with the highest increase among older men. When emergency department users were compared with the general population, the standardised mortality ratio was 1.81 for men and 1.93 for women. Among those attending the ED two, three, or more times in a calendar year, the mortality rate was higher than among those coming only once in a year. The causes of death that led to the highest mortality among frequent users of the ED were neoplasm, ischaemic heart diseases, and external causes, particularly drug intoxication, suicides, and probable suicides. CONCLUSIONS The mortality of those who had used the ED and been discharged home was found to be higher than that of the general population. Frequent users of the ED had a higher mortality than those visiting the department no more than once a year. As the ED serves general medicine and surgery patients, not injuries, the high mortality due to drug intoxication, suicide, and probable suicide is interesting. Further studies are needed into the diagnosis at discharge of those frequently using the ED, in an attempt to understand and possibly prevent this marked mortality rate.