Acute exacerbations in patients with established chronic obstructive pulmonary disease (COPD) are associated with accelerated lung function loss, according to data published in the American Journal of Respiratory and Critical Care Medicine.
Mark T Dransfield, MD, from the Lung Health Center, University of Alabama at Birmingham and the Birmingham VA Medical Center, and colleagues examined 2,000 participants from the Genetic Epidemiology of COPD (COPDGene) study. The participants with and without COPD were current and former smokers with at least a 10 pack-year smoking history.
The researchers collected self-reported acute respiratory event data every 6 months for 5 years. They defined “exacerbations” as acute respiratory symptoms that require antibiotics or systemic steroids, and they defined severe events by the need for hospitalization. The investigators used linear mixed models to measure the decline of excess forced expiratory volume in 1 second based on exacerbations or acute respiratory events.
Among individuals with COPD, exacerbations were associated with a decline in excess forced expiratory volume in 1 second. This association was strongest among individuals in the Global Initiative for Chronic Obstructive Lung Disease (GOLD 1) study. In this population, each exacerbation was associated with an additional 23-mL/year decline, and each severe exacerbation was associated with an 87-mL/year decline. A similar association was observed among the individuals in the GOLD 2 and GOLD 3 studies, although the researchers observed smaller effects.
The results also showed a steeper average decline in excess forced expiratory volume in 1 second among current smokers than among former smokers (9-mL decline vs 2-mL decline). In addition, acute respiratory events were not associated with additional decline in excess forced expiratory volume in 1 second among patients without airflow obstruction.
“Although many current and former smokers without airflow obstruction have respiratory impairment and suffer exacerbation-like respiratory events, we found no evidence that these accelerate lung function loss,” the study authors wrote. “Collectively, these findings support the hypothesis that acute exacerbations contribute to COPD progression, particularly in those with disease that is initially mild.”
- Dransfield MT, Kunisaki KM, Strand MJ, et al. Acute exacerbations and lung function loss in smokers with and without COPD. Am J Respir Crit Care Med. 2016; doi:10.1164/rccm.201605-1014OC.