Pope JH, Aufderheide TP, Ruthazer R, Woolard RH, Feldman JA, Beshansky JR, Griffith JL, Selker HP.
Missed diagnoses of acute cardiac ischemia in the emergency department.
N Engl J Med 2000;342(16):1163-70.
(Comments in: N Engl J Med. 2000;342(16):1207-10. N Engl J Med. 2000;343(20):1492-3; discussion 1493-4. N Engl J Med. 2000;343(20):1492; discussion 1493-4. N Engl J Med. 2000;343(20):1493; discussion 1493-4. N Engl J Med. 2000;343(20):1493; discussion 1493-4.)

The study goals were to determine the rate of misdiagnosed (defined as failure to hospitalize) patients with acute cardiac ischemia (either acute myocardial infarction or unstable angina), to identify clinical and demographic characteristics associated with misdiagnosis, and to estimate 30-day risk-adjusted mortality ratios for all patients and those who were misdiagnosed (not presented by race).

The study sample included patients who participated in a controlled clinical trial of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) and met an age criterion and a series of symptom-based inclusion criteria. Patients were recruited from 10 hospitals in the eastern and midwestern United States. Data were collected from patients at arrival in the emergency room, during hospitalization (for patients hospitalized), during a follow-up evaluation 24 to 72 hours later (for those not hospitalized), and at a 30-day follow-up point. Diagnoses were confirmed by various (objective) measures.

The results showed that patients who were not hospitalized were more likely to be “nonwhite” (4.3% of all black patients versus 1.7% of all white patients; OR for nonwhite race in multivariate analysis=2.2, 95% confidence interval=1.1 to 4.3), have shortness of breath as the chief symptom, and have a normal cardiogram. The racial pattern held for the subsample of patients with acute myocardial infarction (5.8% of black patients versus 1.2% of white patients; OR for nonwhite race in multivariate analysis=4.5, 95% confidence interval=1.8 to 11.8) and for patients with unstable angina (3.0% of black patients versus 2.2% of white patients; this difference was not statistically significant).

The authors state that “blacks have more risk factors for coronary artery disease than whites, but this fact did not appear to have a strong influence on the diagnostic impressions of the physicians.” They also state that the age and gender differences between black and white patients (black patients were on average 8-10 years younger and more likely to be female than white patients) might partially explain why physicians might be less inclined to suspect the presence of acute cardiac ischemia in black patients. The authors conclude that “the incidence of missed diagnoses of acute cardiac ischemia in the emergency department may be reduced by … addressing the clinical factors or misconceptions that obscure the recognition of acute myocardial infarction and unstable angina in women and nonwhite patients.”

The study limitations include the dropping of patients with missing data. Twenty-two percent of all patients and 29% of patients with acute myocardial infarction were dropped from multivariate analyses due to missing data. It is not possible to evaluate how this might bias the race finding from the data provided in the article.