Rule appears to improves diagnostic accuracy for new heart failure
Researchers developed a new rule for diagnosing heart failure, based on a study of primary care patients suspected of having the disease.
Researchers developed a new rule for diagnosing heart failure, based on a study of primary care patients suspected of having the disease.
The cross-sectional study, which was published online Nov. 21 by Circulation, included 721 consecutive Dutch patients with suspected new-onset heart failure. All of the patients underwent a standardized diagnostic workup including a typical history and physical as well as chest X-ray, spirometry, electrocardiogram (ECG), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement. Diagnosis of heart failure was confirmed by six-month follow-up data. Overall, 28.7% of the patients were determined to have heart failure.
The researchers found that heart failure could best be predicted using three items from the patient's history (age, coronary artery disease and loop diuretic use) plus six from the physical examination (pulse rate and regularity, displaced apex beat, rales, heart murmur and increased jugular vein pressure). Together, these factors had a c-statistic of 0.83 for predicting heart failure. Of the supplemental tests performed, NT-proBNP was found to be the most useful. It increased the c-statistic to 0.86 and resulted in a net reclassification improvement of 69% (P<0.0001). After developing a diagnostic rule based on these factors, the researchers validated it with two other datasets, which confirmed the rule's accuracy.
Application of the rule does still leave many patients (54.4% in the studied population) in an intermediate category of diagnostic uncertainty, but researchers believe the rule could be useful in quantifying the probability of heart failure in patients with suggestive symptoms. They noted that the results reinforce the importance of the history and physical and highlight the power of a relatively convenient test, the NT-proBNP. If the NT-proBNP is not available, however, the assessment of alternate diagnostic rules showed that ECG or chest X-ray could also be useful, the authors said.