Table 3.
Association between Imaging Features and Outcomes among Individuals at GOLD Stage 0
| Study | Outcome |
|---|---|
| NELSON (37, 38, 41) | • Among male smokers in a lung cancer screening trial, participants without baseline airflow obstruction who developed obstruction at follow-up had significantly lower mean Perc15 at baseline, −934.2 HU vs. −930.2 HU (P < 0.001), suggesting that greater presence of emphysema at baseline can help identify patients who will go on to develop emphysema. |
| • Participants with upper lobe–predominant emphysema had greater loss in lung function at follow-up than those with lower-lobe emphysema distribution, independent of total emphysema extent. | |
| • Of those with no airflow limitation at baseline, a 1-mm greater Pi10 (measure of airway wall thickness) equated with an OR of 2.45 (P < 0.001), and a 10-HU lower Perc15 had an OR of 1.46 (P < 0.001) for the development of airflow limitation at follow-up. | |
| New York lung cancer screening cohort (39) | • In a small, United States–based study examining lung cancer screening CT scans among 521 participants, the presence of moderate to severe emphysema based on visual assessment was associated with incident airflow obstruction (HR, 5.14). |
| MESA Lung (40, 42) | • Examining only participants without prior diagnosis of chronic lower respiratory disease or use of inhaled corticosteroids or bronchodilators, a greater Pi10 was associated with a 9% faster FEV1 decline (P = 0.012) and incident COPD (OR, 2.22; P < 0.001) at 5-yr follow-up. |
| • Greater Pi10 was associated with a 57% higher risk of hospitalization or mortality related to chronic lower respiratory disease. | |
| • In this study, 5.4% of subjects had an emphysematous lung percentage above the upper limit of normal, and this was associated with increased odds of incident airflow limitation (OR, 4.38), with similar results seen using the emphysematous lung percentage as a continuous measure or using a fixed threshold of 5%. | |
| Korean cohort (35) | • This Korean cohort study of 628 healthy volunteers without known respiratory disease or abnormal PFT results at baseline demonstrated that those with emphysema (defined as ≥10% low-attenuation area based on a −950-HU threshold) had the fastest decline in FVC (−33.9 vs. −18.8 ml/yr; P = 0.02), but emphysema was not associated with incident airflow limitation at follow-up (35). |
| • Although the presence of emphysema was associated with a greater rate of FEV1 decline, the difference was not statistically significant. | |
| Pooled DLCST and ECLIPSE data (36) | • Data pooled from DLCST and ECLIPSE found that among 687 current and former smokers without airflow obstruction, no significant relationship existed between Perc15 and FEV1 decline, whereas these relationships were evident in participants at GOLD stages 2 and 3. |
| COPDGene (44–46) | • CT-identified small-airway abnormalities defined using PRMSAD were associated with excess FEV1 decline at 5 yr among at-risk smokers without airflow obstruction at baseline. |
| • Individuals within the highest PRMSAD quartile (≥16%) demonstrated an FEV1 decline of 49.2 ml/yr as compared with those in the lowest quartile (35.4 ml/yr). | |
| • Additional longitudinal CT analyses suggest that over time, voxels with PRMSAD among at-risk smokers progress to voxels with emphysema. | |
| Pooled data from MESA, CanCOLD, and SPIROMICS (48) | • Comparing the highest to the lowest quartile for mean airway-to-lung ratio in MESA, the COPD incidence rate ratio was 8.12 (95% CI, 3.81–17.27); there was no difference in FEV1 decline. |
| • Comparing the highest to the lowest quartile for mean airway-to-lung ratio in CanCOLD, the COPD incidence rate ratio was 3.33 (95% CI, 1.89–5.85); there was no difference in FEV1 decline. |
Definition of abbreviations: CanCOLD = Canadian Cohort Obstructive Lung Disease; CI = confidence interval; COPD = chronic obstructive pulmonary disease; COPDGene = Genetic Epidemiology of COPD; CT = computed tomography; DLCST = Danish Lung-Cancer Screening Trial; ECLIPSE = Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints; GOLD = Global Initiative for Chronic Obstructive Lung Disease; HR = hazard ratio; HU = Hounsfield units; MESA = Multi-Ethnic Study of Atherosclerosis; NELSON = Dutch–Belgian Lung Cancer Screening trial; OR = odds ratio; Perc15 = 15th percentile point; PFT = pulmonary function test; Pi10 = the square root of the wall area of a theoretical airway with a lumen perimeter of 10 mm; PRMSAD = parametric response mapping small-airway abnormalities; SPIROMICS = Subpopulations and Intermediate Outcome Measures in COPD Study.