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PURPOSE: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide. Impaired lung function is associated with heightened risk for death, cardiovascular events, and COPD exacerbations. However, it is unclear if forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) differ in predictive value. PATIENTS AND METHODS: Data from 16,485 participants in the Study to Understand Mortality and Morbidity (SUMMIT) in COPD were analyzed. Patients were grouped into quintiles for each lung function parameter (FEV1 %predicted, FVC %predicted, FEV1/FVC). The four highest quintiles (Q2-Q5) were compared to the lowest (Q1) to assess their relationship with all-cause mortality, cardiovascular events, and moderate-to-severe and severe exacerbations. Cox-regression was used, adjusted for age, sex, ethnicity, body-mass index, smoking status, previous exacerbations, cardiovascular disease, treatment, and modified Medical Research Council dyspnea score. RESULTS: Compared to Q1 (<53.5% FEV1 predicted), increasing FEV1 quintiles (Q2 53.5-457.5% predicted, Q3 57.5-461.6% predicted, Q4 61.6-465.8% predicted, and Q5 ≥65.8%) were all associated with significantly decreased all-cause mortality (20% (4-34%), 28% (13-40%), 23% (7-36%), and 30% (15-42%) risk reduction, respectively). In contrast, a significant risk reduction (21% (4-35%)) was seen only between Q1 and Q5 quintiles of FVC. Neither FEV1 nor FVC was associated with cardiovascular risk. Increased FEV1 and FEV1/FVC quintiles were also associated with the reduction of moderate-to-severe and severe exacerbations while, surprisingly, the highest FVC quintile was related to the heightened exacerbation risk (28% (8-52%) risk increase). CONCLUSION: Our results suggest that FEV1 is a stronger predictor for all-cause mortality than FVC in moderate COPD patients with heightened cardiovascular risk and that subjects with moderate COPD have very different risks.

Original publication

DOI

10.2147/COPD.S242809

Type

Journal article

Journal

Int j chron obstruct pulmon dis

Publication Date

2020

Volume

15

Pages

1135 - 1142

Keywords

airflow limitation, cardiovascular risk, death rate, exacerbation, lung function, lung volumes, Cardiovascular Diseases, Forced Expiratory Volume, Humans, Pulmonary Disease, Chronic Obstructive, Respiratory Function Tests, Vital Capacity