Prognostic Significance of Large Airway Dimensions on Computed Tomography in the General Population. The Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study

Abstract

Rationale: Large airway dimensions on computed tomography (CT) have been associated with lung function, symptoms, and exacerbations in chronic obstructive pulmonary disease (COPD), as well as with symptoms in smokers with preserved spirometry. Their prognostic significance in persons without lung disease remains undefined.

Objectives: To examine associations between large airway dimensions on CT and respiratory outcomes in a population-based cohort of adults without prevalent lung disease.

Methods: The Multi-Ethnic Study of Atherosclerosis recruited participants ages 45-84 years without cardiovascular disease in 2000-2002; we excluded participants with prevalent chronic lower respiratory disease (CLRD). Spirometry was measured in 2004-2006 and 2010-2012. CLRD hospitalizations and deaths were classified by validated criteria through 2014. The average wall thickness for a hypothetical airway of 10-mm lumen perimeter on CT (Pi10) was calculated using measures of airway wall thickness and lumen diameter. Models were adjusted for age, sex, principal components of ancestry, body mass index, smoking, pack-years, scanner, percent emphysema, genetic risk score, and initial forced expiratory volume in 1 second (FEV₁) percent predicted.

Results: Greater Pi10 was associated with 9% faster FEV₁ decline (95% confidence interval [CI], 2 to 15%; P = 0.012) and increased incident COPD (odds ratio, 2.22; 95% CI, 1.43-3.45; P = 0.0004) per standard deviation among 1,830 participants. Over 78,147 person-years, higher Pi10 was associated with a 57% higher risk of first CLRD hospitalization or mortality (P = 0.0496) per standard deviation. Of Pi10's component measures, both greater airway wall thickness and narrower lumen predicted incident COPD and CLRD clinical events.

Conclusions: In adults without CLRD, large airway dimensions on CT were prospectively associated with accelerated lung function decline and increased risks of COPD and CLRD hospitalization and mortality.

Keywords: chronic obstructive pulmonary disease; computed tomography; lung function; risk stratification.

Figure 1.

Flowchart of Multi-Ethnic Study of Atherosclerosis (MESA) participants included in the present study. CLRD = chronic lower respiratory disease. CT = computed tomography; Pi10 = average wall thickness for a hypothetical airway of 10-mm lumen perimeter on computed tomography.

Figure 2.

Stratified associations between average wall thickness for a hypothetical airway of 10-mm lumen perimeter on computed tomography (Pi10) and annual change in forced expiratory volume in 1 second (FEV₁) over five years of follow-up, with 95% confidence intervals, in participants without initial airflow limitation or prevalent clinical chronic lower respiratory disease. Fully adjusted models include age, sex, race/ethnicity, body mass index (BMI), smoking status, pack-years, percent emphysema, voxel size, and computed tomography (CT) scanner type. EBT = electron beam computed tomography; MDCT = multidetector computed tomography; PM_2.5 = particulate matter less than or equal to 2.5 μm in aerodynamic diameter; SD = standard deviation.

Figure 3.

Generalized additive model of associations between average wall thickness for a hypothetical airway of 10-mm lumen perimeter on computed tomography (Pi10) and risk of first hospitalization or mortality due to chronic lower respiratory disease (CLRD) over fourteen years of follow-up in participants without prevalent clinical CLRD. The model is fully adjusted for age, sex, race/ethnicity, body mass index, smoking status, pack-years, percent emphysema, voxel size, and computed tomography scanner type.