Reply: the lung immune response to bacteria in chronic obstructive pulmonary disease

Association between visual emphysema and lung nodules on low-dose CT scan in a Chinese Lung Cancer Screening Program (Nelcin-B3)

OBJECTIVES

This study aimed to evaluate the association between visual emphysema and the presence of lung nodules, and Lung-RADS category with low-dose CT (LDCT).

METHODS

Baseline LDCT scans of 1162 participants from a lung cancer screening study (Nelcin-B3) performed in a Chinese general population were included. The presence, subtypes, and severity of emphysema (at least trace) were visually assessed by one radiologist. The presence, size, and classification of non-calcified lung nodules (≥ 30 mm³) and Lung-RADS category were independently assessed by another two radiologists. Multivariable logistic regression and stratified analyses were performed to estimate the association between emphysema and lung nodules, Lung-RADS category, after adjusting for age, sex, BMI, smoking status, pack-years, and passive smoking.

RESULTS

Emphysema and lung nodules were observed in 674 (58.0%) and 424 (36.5%) participants, respectively. Participants with emphysema had a 71% increased risk of having lung nodules (adjusted odds ratios, aOR: 1.71, 95% CI: 1.26-2.31) and 70% increased risk of positive Lung-RADS category (aOR: 1.70, 95% CI: 1.09-2.66) than those without emphysema. Participants with paraseptal emphysema (n = 47, 4.0%) were at a higher risk for lung nodules than those with centrilobular emphysema (CLE) (aOR: 2.43, 95% CI: 1.32-4.50 and aOR: 1.60, 95% CI: 1.23-2.09, respectively). Only CLE was associated with positive Lung-RADS category (p = 0.02). CLE severity was related to a higher risk of lung nodules (ranges aOR: 1.44-2.61, overall p < 0.01).

CONCLUSION

In a Chinese general population, visual emphysema based on LDCT is independently related to the presence of lung nodules (≥ 30 mm³) and specifically CLE subtype is related to positive Lung-RADS category. The risk of lung nodules increases with CLE severity.

KEY POINTS

• Participants with emphysema had an increased risk of having lung nodules, especially smokers. • Participants with PSE were at a higher risk for lung nodules than those with CLE, but nodules in participants with CLE had a higher risk of positive Lung-RADS category. • The risk of lung nodules increases with CLE severity.

Pathophysiology of Emphysema and Implications

This article serves as a CME-available, enduring material summary of the following COPD9_USA presentations: "Overview of Lung Injury in COPD: Types and Key Questions" Presenter: Caroline Owen, MD, PhD Emphysema as a Disease of Deficient Tissue Repair/Maintenance" Presenter: Rubin Tuder, MD.

Inflammation in chronic obstructive pulmonary disease and its role in cardiovascular disease and lung cancer

Chronic obstructive pulmonary disease (COPD) is characterized by lung inflammation that persists after smoking cessation. This inflammation is heterogeneous but the key inflammatory cell types involved are macrophages, neutrophils and T cells. Other lung cells may also produce inflammatory mediators, particularly the epithelial cells. The main inflammatory mediators include tumor necrosis factor alpha, interleukin-1, interleukin-6, reactive oxygen species and proteases. COPD is also associated with systemic inflammation and there is a markedly increased risk of cardiovascular disease (particularly coronary artery disease) and lung cancer in patients with COPD. There is strong associative evidence that the inflammatory cells/mediators in COPD are also relevant to the development of cardiovascular disease and lung cancer. There are a large number of potential inhibitors of inflammation in COPD that may well have beneficial effects for these comorbidities. This is a not well-understood area and there is a requirement for more definitive clinical and mechanistic studies to define the relationship between the inflammatory process of COPD and cardiovascular disease and lung cancer.