January 21, 2010Open Access

Ruling out coronary heart disease in primary care patients with chest pain: a clinical prediction score

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Coronary heart disease in patients with chest pain (n=1446). Intervention: Ambulatory CHD predictive score. Primary outcome: Area under the receiver operating characteristics (ROC) curve for ruling out coronary heart disease (AUC 0.95, 95% CI 0.92-0.97).

Key Result

The ambulatory coronary heart disease score, based on history and physical examination, demonstrated an area under the curve of 0.95 for ruling out coronary heart disease in primary care patients.

Study Design

Type

Cohort (n=1,446)

Multicenter

Yes

PICO

Population

Coronary heart disease in patients with chest pain (n=1,446)

Intervention / Comparator

Ambulatory CHD predictive score

Primary Outcome

Area under the receiver operating characteristics (ROC) curve for ruling out coronary heart disease — AUC 0.95 (0.92-0.97)

Main Result

Effect estimate: AUC 0.95 (95% CI 0.92-0.97)

Limitations

Scores derived from logistic regression cannot identify unusual presentations
Used delayed diagnosis instead of referring all patients to a specialist
Assessors in the derivation cohort were not blinded to the initial state of exposure when defining cases
Cannot exclude that patients with MI or unstable angina which rapidly became entirely asymptomatic remained undetected
Underpowered to detect any difference in myocardial infarction or unstable angina between the risk groups
External validation showed the score to be much less sensitive than it was meant to be

Abstract

BACKGROUND: Chest pain raises concern for the possibility of coronary heart disease. Scoring methods have been developed to identify coronary heart disease in emergency settings, but not in primary care. METHODS: Data were collected from a multicenter Swiss clinical cohort study including 672 consecutive patients with chest pain, who had visited one of 59 family practitioners' offices. Using delayed diagnosis we derived a prediction rule to rule out coronary heart disease by means of a logistic regression model. Known cardiovascular risk factors, pain characteristics, and physical signs associated with coronary heart disease were explored to develop a clinical score. Patients diagnosed with angina or acute myocardial infarction within the year following their initial visit comprised the coronary heart disease group. RESULTS: The coronary heart disease score was derived from eight variables: age, gender, duration of chest pain from 1 to 60 minutes, substernal chest pain location, pain increasing with exertion, absence of tenderness point at palpation, cardiovascular risks factors, and personal history of cardiovascular disease. Area under the receiver operating characteristics curve was of 0.95 with a 95% confidence interval of 0.92; 0.97. From this score, 413 patients were considered as low risk for values of percentile 5 of the coronary heart disease patients. Internal validity was confirmed by bootstrapping. External validation using data from a German cohort (Marburg, n = 774) revealed a receiver operating characteristics curve of 0.75 (95% confidence interval, 0.72; 0.81) with a sensitivity of 85.6% and a specificity of 47.2%. CONCLUSIONS: This score, based only on history and physical examination, is a complementary tool for ruling out coronary heart disease in primary care patients complaining of chest pain.

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