Age-dependent values of N-terminal pro-B-type natriuretic peptide are superior to a single cut-point for ruling out suspected systolic dysfunction in primary care.
OBJECTIVE
The study evaluated the use of age-related decision limits for N-terminal pro-B-type natriuretic peptide (NT-proBNP), for ruling out suspected systolic dysfunction in symptomatic patients in primary care, compared with the present standards.


RESULTS
Data were obtained from 5508 patients from 10 studies in the UK, New Zealand, Europe, and USA. All have had NT-proBNP analysis and echocardiography. The median age was 62 years (range 18-100 years) with a prevalence of reduced left ventricular systolic function (left ventricular ejection fraction < or =40%) of 18%. In a receiver operating characteristic curve analysis, overall area under the curve (AUC) was 0.89. When looking at different age groups, AUC was highest (0.95) for <50 years, intermediate (0.90) for 50-75 years, and lowest (0.82) for >75 years. Using optimized decision limits, sensitivity, specificity, and negative predictive values (NPVs) were: <50 years (50 ng/L): 99.2, 57.2, and 99.7%; 50-75 years (75 ng/L): 95.9, 51.0, and 96.8%; and >75 years (250 ng/L): 87.9, 53.7, and 92.4%, respectively. Using only a single decision value (125 ng/L for all ages) gave sensitivities of 89.1, 91.9, and 94.3%; specificities of 84.0, 69.1, and 29.3% and NPVs of 97.7, 97.6, and 93.4%. A decision value of 400 ng/L for all ages gave much lower sensitivities.


CONCLUSIONS
In a large population of patients in primary care, the use of age-stratified NT-proBNP decision limits considerably improves performance over current standards, with an excellent NPV for exclusion of reduced left ventricular systolic function.
Hildebrandt
Per
P
Department of Cardiology and Medicine, Glostrup University Hospital, Glostrup, Denmark. p.hildebrandt@dadlnet.dk
Collinson
Paul O
PO
Doughty
Robert N
RN
Fuat
Ahmet
A
Gaze
David C
DC
Gustafsson
Finn
F
Januzzi
James
J
Rosenberg
Jens
J
Senior
Roxy
R
Richards
Mark
M
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D054143:Heart Failure, Systolic / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D012372:ROC Curve; D012016:Reference Values; D012680:Sensitivity and Specificity; D055815:Young Adult
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain