Increased odds for acute respiratory disease with lung abnormality growth in smokers

Key takeaways:

• Individuals with more vs. less quantitative interstitial abnormality progression experienced more severe acute respiratory disease events.
• Findings from this study continued to be seen after adjustment.

The odds for severe acute respiratory disease events rose among previous/current smokers with evidence of quantitative interstitial abnormality, or QIA, progression on CT scans, according to results published in Radiology.

“QIA includes features like reticulation and ground-glass opacities as well as subtle density changes with important clinical implications,” Bina Choi, MD, associate physician in the division of pulmonary and critical care medicine at Brigham and Women’s Hospital and postdoctoral fellow at the Applied Chest Imaging Laboratory at Harvard Medical School, said in a press release.

“In some patients, QIA may be a precursor to advanced diseases such as pulmonary fibrosis or emphysema,” she added.

In this analysis, Choi and colleagues evaluated chest CT scans from 3,972 individuals (mean age, 60.7 years; 53.4% women; 76.1% non-Hispanic white; 43.7% current smokers) who had at least a 10 pack-year smoking history to find out if there is a relationship between QIA progression and acute respiratory disease (ARD), as well as severe ARD events.

Researchers had individuals fill out questionnaires every 3 to 6 months to report ARD episodes (cough or dyspnea for 48 hours that requires antibiotics/corticosteroids) and severe ARD episodes (ED visit/hospitalization).

Within the study population, 35.1% of individuals reported at least one ARD event between baseline and the 5-year follow-up (mean, 4.4 events), which was slightly less than the percentage of individuals who reported an ARD event after the follow-up (39.7%; mean, 3.9 events). Severe ARD events occurred more frequently after follow-up vs. between baseline and follow-up (22.2% vs. 15.8%).

Using comorbidity-adjusted regression models, researchers found a link between annual percentage QIA progression and elevated odds for at least one severe ARD event between baseline and 5 years (OR = 1.29; 95% CI, 1.06-1.56).

The odds for a severe ARD event after the 5-year follow-up also went up with annual percentage QIA progression (OR = 1.26; 95% CI, 1.05-1.52).

In terms of non-severe ARD events, the odds for this outcome significantly increased with annual percentage QIA progression after the 5-year follow-up (OR = 1.18; 95% CI, 1-1.4) but not between baseline and follow-up.

Notably, the rate of severe ARD events between baseline and follow-up rose by 40% with each annual QIA progression increase of 1%, according to researchers.

To compare outcomes based on faster vs. slower QIA progression, the total cohort was divided into quartiles. The highest quartile included those with 1.2% or more QIA progression, and the lowest quartile included those with –1.7% or less QIA progression.

Between these two groups, researchers observed a higher incidence of ARD events between baseline and 5 years among those in the highest quartile (incidence rate ratio [IRR] = 1.46; 95% CI, 1.14-1.86).

Individuals with more vs. less QIA progression also experienced more severe ARD events between baseline and 5 years (IRR = 1.79; 95% CI, 1.18-2.73), according to researchers.

The significant link between annual percentage QIA progression and a heightened likelihood for severe ARD events between baseline and follow-up and after follow-up continued to be found following adjustment for several conditions (coronary artery disease, congestive heart failure, diabetes, hypertension and high cholesterol), as well as total lung volume.

“Future studies incorporating mechanistic and omics data may be used to gain biologic and clinical insight into the associations of QIA and severe ARD events, and future studies should use micro-CT imaging to understand the role of the small airways in QIA progression,” Choi and colleagues wrote.

Reference:

• Lung abnormality progression linked to acute respiratory disease in smokers. https://www.eurekalert.org/news-releases/1042222. Published April 30, 2024. Accessed April 30, 2024.