New concepts for expressing forced expiratory volume in 1 s arising from survival analysis.
Eur Respir J
; 35(4): 873-82, 2010 Apr.
Article
in En
| MEDLINE
| ID: mdl-19741033
ABSTRACT
Spirometric lung function is partly determined by sex, age and height (Ht). Commonly, lung function is expressed as a percentage of the predicted value (PP) in order to account for these effects. Since the PP method retains sex, age and Ht bias, forced expiratory volume in 1 s (FEV(1)) standardised by powers of Ht and by a new sex-specific lower limit (FEV(1) quotient (FEV(1)Q)) were investigated to determine which method best predicted all-cause mortality in >26,967 patients and normal subjects. On multivariate analysis, FEV(1)Q was the best predictor, with a hazard ratio for the worst decile of 6.9 compared to 4.1 for FEV(1)PP. On univariate analysis, the hazard ratios were 18.8 compared to 6.1, respectively; FEV(1) x Ht(-3) was the next-best predictor of survival. Median survival was calculated for simple cut-off values of FEV(1)Q and FEV(1) x Ht(-3). These survival curves were accurately fitted (r(2) = 1.0) by both FEV(1)Q and FEV(1) x Ht(-3) values expressed polynomially, and so an individual's test result could be used to estimate survival (with sd for median survival of 0.22 and 0.61 yrs, respectively). It is concluded that lung function impairment should be expressed in a new way, here termed the FEV(1)Q, or, alternatively, as FEV(1) x Ht(-3), since these indices best relate spirometric lung function to all-cause mortality and survival.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Spirometry
/
Forced Expiratory Volume
/
Lung Diseases
Type of study:
Prognostic_studies
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Eur Respir J
Year:
2010
Type:
Article
Affiliation country:
United kingdom