Derivation and validation of a simple clinical risk-model in heart failure based on 6 minute walk test performance and NT-proBNP status--do we need specificity for sex and beta-blockers?
BACKGROUND
It is unclear whether risk prediction strategies in chronic heart failure (CHF) need to be specific for sex or beta-blockers. We examined this problem and developed and validated the consequent risk models based on 6-minute-walk-test and NT-proBNP.


METHODS
The derivation cohort comprised 636 German patients with systolic dysfunction. They were validated against 676 British patients with similar aetiology. ROC-curves for 1-year mortality identified cut-off values separately for specificity (none, sex, beta-blocker, both). Patients were grouped according to number of cut-offs met (group I/II/III - 0/1/2 cut-offs).


RESULTS
Widest separation between groups was achieved with sex- and beta-blocker-specific cut offs. In the derivation population, 1-year mortality was 0%, 8%, 31% for group I, II and III, respectively. In the validation population, 1-year rates in the three risk groups were 2%, 7%, 14%, respectively, after application of the same cut-offs.


CONCLUSIONS
Risk stratification for CHF should perhaps take sex and beta-blocker usage into account. We derived and independently validated relevant risk models based on 6-minute-walk-tests and NT-proBNP. Specifying sex and use of beta-blockers identified three distinct sub-groups with widely differing prognosis. In clinical practice, it may be appropriate to tailor the intensity of follow-up and/or the treatment strategy according to the risk-group.
Frankenstein
L
L
Department of Cardiology, Angiology, Pulmonology,Universitätsklinikum Heidelberg,, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany. Lutz.Frankenstein@med.uni-heidelberg.de
Goode
K
K
Ingle
L
L
Remppis
A
A
Schellberg
D
D
Nelles
M
M
Katus
H A
HA
Clark
A L
AL
Cleland
J G F
JG
Zugck
C
C
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005080:Exercise Test / Q000592:standards*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000097:blood* / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D016016:Proportional Hazards Models; D011498:Protein Precursors / Q000097:blood*; D011597:Psychomotor Performance / Q000502:physiology; D012307:Risk Factors; D012727:Sex Characteristics; D013997:Time Factors; D016138:Walking / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D010446:Peptide Fragments; D011498:Protein Precursors; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain