COPD prognosis in relation to diagnostic criteria for airflow obstruction in smokers.
Pubmed ID: 23563262
Journal: The European respiratory journal
Publication Date: 01/01/2014
Affiliation: Radboud university medical center, Nijmegen.
MeSH Terms: Humans, Male, Adult, Female, Middle Aged, Smoking, Disease Progression, Forced Expiratory Volume, Vital Capacity, Prognosis, Severity of Illness Index, Pulmonary Disease, Chronic Obstructive, Airway Obstruction
Authors: Akkermans RP, Biermans M, Robberts B, ter Riet G, Jacobs A, van Weel C, Wensing M, Schermer T
Cite As: Akkermans RP, Biermans M, Robberts B, ter Riet G, Jacobs A, van Weel C, Wensing M, Schermer T. COPD prognosis in relation to diagnostic criteria for airflow obstruction in smokers. Eur Respir J 2014 Jan;43(1):54-63. Epub 2013 Apr 5.
The aim of this study was to establish which cut-off point for the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio (i.e. fixed 0.70 or lower limit of normal (LLN) cut-off point) best predicts accelerated lung function decline and exacerbations in middle-aged smokers. We performed secondary analyses on the Lung Health Study dataset. 4045 smokers aged 35-60 years with mild-to-moderate obstructive pulmonary disease were subdivided into categories based on presence or absence of obstruction according to both FEV1/FVC cut-off points. Post-bronchodilator FEV1 decline served as the primary outcome to compare subjects between the categories. 583 (14.4%) subjects were nonobstructed and 3230 (79.8%) subjects were obstructed according to both FEV1/FVC cut-off points. 173 (4.3%) subjects were obstructed according to the fixed cut-off point, but not according to the LLN cut-off point ("discordant" subjects). Mean±SE post-bronchodilator FEV1 decline was 41.8±2.0 mL·year(-1) in nonobstructed subjects, 43.8±3.8 mL·year(-1) in discordant subjects and 53.5±0.9 mL·year(-1) in obstructed subjects (p<0.001). Our study showed that FEV1 decline in subjects deemed obstructed according to a fixed criterion (FEV1/FVC <0.70), but non-obstructed by a sex- and age-specific criterion (LLN) closely resembles FEV1 decline in subjects designated as non-obstructed by both criteria. Sex and age should be taken into account when assessing airflow obstruction in middle-aged smokers.