Smokers with Lung Abnormalities More Likely to Report Severe Acute Respiratory Disease Events

Cigarette-smokers with quantitative interstitial abnormalities (QIAs) in their CT scans maintain a greater likelihood of having severe acute respiratory disease (ARD) events, according to recent findings.¹

These conclusions were the results of a new study conducted to find out whether QIA progression during patients’ CT scans showed an association with ARD or severe ARD reports among those who have a smoking history. This research was led by Bina Choi, MD, of Brigham and Women’s Hospital.

Choi et al. wrote that severe ARD, or episodes requiring hospitalization, are often called chronic obstructive pulmonary disease (COPD) exacerbations in those with an underlying COPD diagnosis, despite the fact that ARD events can be seen even among those who do smoke but do not have COPD or show spirometric obstruction or emphysema during their imaging.²

“Although many ARD events are likely related to airway disease and COPD, some may instead be associated with QIA,” Choi and colleagues wrote. “Thus, the aim of the current study was to determine whether QIA progression at CT is associated with ARD and severe ARD events in individuals with a history of smoking.”

Background and Methods

The research team’s work was actually a secondary analysis of a prospective observational study referred to as the COPDGene Study, including 10,198 subjects that had a history of smoking and were from 21 centers around the US. Those eligible had to have a smoking history of 10 pack-years or more, have been aged 45 - 80 years, and to be non-Hispanic Black or non-Hispanic White.¹

The team gathered data at baseline during the first visit between November 2007 - April 2011, and the second visit about 5 years later between February 2013 - July 2017, with the data including serum laboratory tests, questionnaires, CT scans, and spirometry. The investigators also did longitudinal follow-up through an assessment of ARD and severe ARD reports using regular questionnaires in a period of every 3 - 6 months.

The research team assessed the progression of QIAs between the point of baseline and subjects’ 5-year follow-up chest CT scans. Episodes of ARD were defined by the team as increased coughing or dyspnea which takes place over 48 hours and requires antibiotics or corticosteroids.

The team defined severe ARD episodes as those necessitating emergency room visits or hospitalization. Either type of episodes were reported through the use of the team’s periodic questionnaires.

The investigators broadly defined progression in QIAs and emphysema as any reported increases that were observed by subjects between the first and second visit.

Findings

There were 3972 individuals recruited for the study, a mean age of 60.7 years at the point of baseline, and 53.4% of these subjects were women. The investigators reported that a higher annual percentage of progression of QIAs was linked to rises in the odds of experiencing 1 or more intercurrent severe ARD events (odds ratio [OR] = 1.29 [95% CI: 1.06, 1.56]; P = .01) in addition to subsequent severe ARD events (OR = 1.26 [95% CI: 1.05, 1.52]; P = .02).

The research team also found that subjects in the highest quartile of QIA progression (≥1.2%) were shown to have had a higher incidence rate of severe ARD events (IRR = 1.79 [95% CI: 1.18, 2.73]; P = .006) and intercurrent ARD events (incidence rate ratio [IRR] = 1.46 [95% CI: 1.14, 1.86]; P = .003) compared to individuals found in the lowest quartile (≤−1.7%).

“These results suggest that QIA progression may represent changes in several parenchymal processes that have short-term intercurrent as well as long-term subsequent impacts on patient symptoms and exacerbations,” they wrote. “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.”

References

1. ^{Choi B, Díaz AA, San José Estépar R, Enzer N, Castro V, Han MK, Washko GR, San José Estépar R, Ash SY; COPDGene Study. Association of Acute Respiratory Disease Events with Quantitative Interstitial Abnormality Progression at CT in Individuals with a History of Smoking. Radiology. 2024 Apr;311(1):e231801. doi: 10.1148/radiol.231801. PMID: 38687222.}
2. ^{Bowler RP, Kim V, Regan E, et al. Prediction of acute respiratory disease in current and former smokers with and without COPD. Chest 2014;146(4):941–950.}