A new decision support tool, the CoDE-HF score, can help diagnose acute heart failure more accurately than current tests based on natriuretic peptide testing alone, according to an international collaboration.
The tool, which combines continuous N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations with clinical characteristics, rules in and rules out acute heart failure more accurately than any approach using fixed NT-proBNP thresholds alone, they report in the BMJ.
While current guidelines recommend the use of an NT-proBNP threshold of 300 pg/mL to rule out acute heart failure, the researchers said its usefulness in real world settings was limited due to concerns about its accuracy in patient subgroups such as older patients and those with comorbidities such as renal disease and obesity.
In a meta-analysis of data for 10,369 patients in 14 studies, they found that the guideline-recommended NT-proBNP threshold to rule out acute heart failure had good performance in younger patients and women. However, the negative predictive value was substantially lower in older patients and in those with obesity or previous heart failure, for whom the false-negative rates were between one in 10 and one in five.
Age-stratified thresholds performed well to rule in the diagnosis of acute heart failure but the positive predictive value was lower in younger patients, their evaluation found.
Similarly, optimised NT-proBNP thresholds of 100 pg/mL to rule out and 1,000 pg/mL to rule in acute heart failure had excellent negative and positive predictive values in the overall population, but performance was lower in older patients and in those with previous heart failure and obesity.
Led by researchers from Scotland, the Collaboration for the Diagnosis and Evaluation of Heart Failure (CoDE-HF) investigators then used statistical models to develop and validate diagnostic scores that would classify the highest proportion of patients as having a high or low probability of acute heart failure with optimal performance to rule in (75% positive predictive value and 90% specificity) and rule out (98% negative predictive value and 90% sensitivity) acute heart failure.
They used NT-proBNP concentrations as a continuous measure, combined with clinical variables known to be associated with acute heart failure, such as age, eGFR, haemoglobin, BMI, heart rate and BP.
In validation exercises they found that the CoDE-HF score had excellent discrimination across all subgroups of patients.
If used in patients with suspected acute heart failure, CoDE-HF would identify 40.3% at low probability and 28.0% at high probability of acute heart failure, they said.
In patients with previous heart failure, the CoDE-HF tool achieved a positive predictive value of 92.7% and specificity of 90.2%, and would identify 45.5% of patients as having a high probability of acute heart failure.
The researchers said the CoDE-HF score used routinely collected variables and therefore could be a simple and practical tool in the triage of patients with suspected acute heart failure.
“We anticipate that use of CoDE-HF to guide more accurate and judicious use of specialist services such as echocardiography could lead to significant cost and efficiency savings for healthcare systems. Additionally, cost savings could also be made by triaging patients at low risk to outpatient care,” they concluded.