Why do we 'over diagnose' unstable angina in the medical emergency room?

Introduction and methods

Work in the Medical Emergency Room (ER) of the University Hospital Rebro is supervised by one of the medical ICU staff (working days 8 am–2 pm) or a senior specialist from another medical department (afternoons, nights, weekends). In this retrospective study we have analyzed all the patients (n = 363) with unstable angina (UA), admitted through the ER in 2002. The aim was to determine the quantity and characteristics of 'overdiagnosed' patients. Anthropological data, data from the ER admission charts (hour of admission, duration of examination, history of coronary artery disease [CAD] or myocardial infarction [MI], arterial hypertension, diabetes, high cholesterol and smoking) and data from the hospital stay were analyzed.

Results

The majority of patients (n = 255) did prove to have an ischemic heart pain (group A), 59 of them developed MI and 196 had angina and were treated accordingly. The rest of the patients could be divided into two groups: patients with no heart condition (group B, n = 62) discharged as musculoskeletal pain (n = 54), cholecystitis (n = 3), gastritis (n = 2), depression (n = 1), sepsis (n = 1) or meningitis (n = 1); and patients with cardiovascular disease but no actual ischemia (group C, n = 46) discharged as heart failure (n = 18), hypertension (n = 16), tachycardia (n = 5), bradycardia (n = 3), dissection of aorta (n = 2) and pulmonary embolism (n = 2).

There were no statistically significant differences in gender between the groups. Patients in groups B and C were older than those in group A (P < 0.05), the significance is even greater when comparing only groups A and B (P < 0.005). Duration of examination in the ER did not influence the accuracy of diagnosis, patients in groups B and C were even longer examined (P < 0.05). We have found that the proportion of patients with history of angina or MI was greater in group A than group B or C (55.1%, 31.1% and 31.3%, respectively) and this was statistically significant (P < 0.005). Smoking, high cholesterol, hypertension, and diabetes did not significantly differ between the groups. Interestingly, we have found that proportion of patients admitted during the afternoons, nights or weekends was higher in groups B and C than in group A (P < 0.05), although characteristics of these patients did not differ from those admitted during the 'ICU staff shift'.

Discussion

Although mistakes in diagnosing UA are inevitable, some progress could surely be made. A smaller proportion of 'overdiagnosing' while ICU staff is supervising the ER could be explained with greater experience in the field. Older patients and patients with a history of angina or MI presenting with chest pain could be admitted with greater certainty of UA. Other risk factors seem to be of little help in our population.