Missed diagnoses of acute cardiac ischemia in the emergency department

Background: Discharging patients with acute myocardial infarction or unstab le angina from the emergency department because of missed diagnoses can hav e dire consequences. We studied the incidence of, factors related to, and c linical outcomes of failure to hospitalize patients with acute cardiac isch emia. Methods: We analyzed clinical data from a multicenter, prospective clinical trial of all patients with chest pain or other symptoms suggesting acute c ardiac ischemia who presented to the emergency departments of 10 U.S. hospi tals. Results: Of 10,689 patients, 17 percent ultimately met the criteria for acu te cardiac ischemia (8 percent had acute myocardial infarction and 9 percen t had unstable angina), 6 percent had stable angina, 21 percent had other c ardiac problems, and 55 percent had noncardiac problems. Among the 889 pati ents with acute myocardial infarction, 19 (2.1 percent) were mistakenly dis charged from the emergency department (95 percent confidence interval, 1.1 to 3.1 percent); among the 966 patients with unstable angina, 22 (2.3 perce nt) were mistakenly discharged (95 percent confidence interval, 1.3 to 3.2 percent). Multivariable analysis showed that patients who presented to the emergency department with acute cardiac ischemia were more likely not to be hospitalized if they were women less than 55 years old (odds ratio for dis charge, 6.7; 95 percent confidence interval, 1.4 to 32.5), were nonwhite (o dds ratio, 2.2; 1.1 to 4.3), reported shortness of breath as their chief sy mptom (odds ratio, 2.7; 1.1 to 6.5), or had a normal or nondiagnostic elect rocardiogram (odds ratio, 3.3; 1.7 to 6.3). Patients with acute infarction were more likely not to be hospitalized if they were nonwhite (odds ratio f or discharge, 4.5; 95 percent confidence interval, 1.8 to 11.8) or had a no rmal or nondiagnostic electrocardiogram (odds ratio, 7.7; 95 percent confid ence interval, 2.9 to 20.2). For the patients with acute infarction, the ri sk-adjusted mortality ratio for those who were not hospitalized, as compare d with those who were, was 1.9 (95 percent confidence interval, 0.7 to 5.2) , and for the patients with unstable angina, it was 1.7 (95 percent confide nce interval, 0.2 to 17.0). Conclusions: The percentage of patients who present to the emergency depart ment with acute myocardial infarction or unstable angina who are not hospit alized is low, but the discharge of such patients may be associated with in creased mortality. Failure to hospitalize is related to race, sex, and the absence of typical features of cardiac ischemia. Efforts to reduce the numb er of missed diagnoses are warranted. (N Engl J Med 2000;342:1163-70.) (C) 2000, Massachusetts Medical Society.