COPD patients who are former smokers have greater decline in lung density and accelerated progression of emphysema if they experience frequent exacerbations, according to a study published in the Annals of the American Thoracic Society.^1,2

A team of researchers from across the United States analysed data of 3874 adults, who were a part of the COPDGene (Genetic Epidemiology of chronic obstructive pulmonary disease) study. Women comprised 50% of the study population, which included 1522 of current smokers and 2352 of former persistent smokers. The patients were evaluated via spirometry and CT scan at the time of study entry and 5 years later. They were monitored every 3-6 months to determine the frequency of exacerbations requiring the use of systemic steroids or antibiotics. Using this data, they sought to examine if acute exacerbations correlated with faster progression of emphysema.

Patients who were former smokers and reported more frequent exacerbations were found to have bigger declines in lung density after adjusting for variables such as age, sex, race and BMI. The lung density decreased by –5.22 g/L among former smokers with ≥ 5 exacerbations vs –4.16 g/L among those with 1-4 exacerbations vs –3.27 g/L among patients who did not suffer any exacerbations. When former smokers with at least 5% emphysema at the time of their enrollment were assessed, the observations were comparable (5 exacerbations –5.92 g/L, 1-4 exacerbations –4.68 g/L and no exacerbations, –3.73 g/L). However, no such associations were noted among current or former smokers with less than 5% emphysema.

Among participants who were current smokers, the decline in lung density was greater vis a vis former smokers. Among those who experienced ≥ 5 exacerbations, lung density decreased by –5.61 g/L vs 5.58 g/L in patients with 1-4 exacerbations vs –4.89 g/L among patients with no exacerbations. However, “researchers did not find the same effect modification that they found in the former smoker group”.²

These findings show that the loss of lung density increased as the exacerbation frequency increased during the 5 years of the study. This change was particularly evident among former smokers who had some degree of underlying emphysema at baseline indicating progression of emphysema.

Prevention of exacerbation is a major goal of management of COPD to prevent decline in lung function and improve quality of life. To this can be added, preventing development of and progression of emphysema, a progressive and irreversible condition, as evident from this analysis of the COPDGene study.

References

1. Bhatt SP, et al. Acute exacerbations are associated with progression of emphysema. Ann Am Thorac Soc. 2022 Dec;19(12):2108-2111. doi: 10.1513/AnnalsATS.202112-1385RL.
2. https://www.healio.com/news/pulmonology/20230119/exacerbations-hasten-emphysema-progression-in-former-smokers-with-copd#:~:text=Exacerbations%20of%20COPD%20involve%20episodes,well%20as%20quality%20of%20life. Dated Jan. 19, 2023, Accessed on Jan. 23, 2023.