Differences between chest pain observation service patients and admitted ''rule-out myocardial infarction'' patients

Objective: To compare and contrast the patient characteristics of ED patients at low risk for acute cardiac ischemia who were assigned to a chest pain observation service vs those admitted to a monitored inpatient bed for ''rule-out acute myocardial infarction'' (R/O MI). Methods: This was a retrospective, cross-sectional comparison of adult patients considered at relatively low risk for cardiac ischemia and who were evaluated in 1 of 2 settings: a short-term observation service and an inpatient monitored bed. All patients had an ED final diagnosis of ''chest pain,'' ''R/O MI,'' or ''unstable angina'' during the 7-month study period. Demographic features and presenting clinical features were examined as a function of site of patient evaluation. Results: Of 531 study patients, 265 (50%) were assigned to the observation service, Younger age (OR = 1.75, 95% CI 1.26, 2.44, for each decrement of 20 years), the complaint of ''chest pain'' (OR = 2.35, 95% CI 1.34, 4.12), and the absence of prior known coronary artery disease (OR = 1.64, 95% CI 1.13, 2.38) were the principal independent factors associated with assignment to a chest pain observation service bed. Conclusions: Patients evaluated in a chest pain observation service appear to have different clinical characteristics than other individuals admitted to a monitored inpatient bed for ''R/O MI.'' Investigators should address differences in clinical characteristics when making outcome comparisons between these 2 patient groups.