Prevalence, Symptom Burden, and Underdiagnosis of Chronic Obstructive Pulmonary Disease in a Lung Cancer Screening Cohort

Abstract

Rationale: Individuals eligible for lung cancer screening (LCS) by low-dose computed tomography (LDCT) are also at risk of chronic obstructive pulmonary disease (COPD) due to age and smoking exposure. Whether the LCS episode is useful for early detection of COPD is not well established.Objectives: To explore associations between symptoms, comorbidities, spirometry, and emphysema in participants enrolled in the Lung Screen Uptake Trial.Methods: This cross-sectional study was a prespecified analysis nested within Lung Screen Uptake Trial, which was a randomized study testing the impact of differing invitation materials on attendance of 60- to 75-year-old smokers and ex-smokers to a "lung health check" between November 2015 and July 2017. Participants with a smoking history ≥30 pack-years and who quit ≤15 years ago, or meeting a lung cancer risk of ≥1.51% via the Prostate Lung Colorectal Ovarian model or ≥2.5% via the Liverpool Lung Project model, were offered LDCT. COPD was defined and classified according to the GOLD (Global Initiative for Obstructive Lung Disease) criteria using prebronchodilator spirometry. Analyses included the use of descriptive statistics, chi-square tests to examine group differences, and univariable and multivariable logistic regression to explore associations between symptom prevalence, airflow limitation, and visually graded emphysema.Results: A total of 560 of 986 individuals included in the analysis (57%) had prebronchodilator spirometry consistent with COPD; 67% did not have a prior history of COPD and were termed "undiagnosed." Emphysema prevalence in those with known and "undiagnosed" COPD was 73% and 68%, respectively. A total of 32% of those with "undiagnosed COPD" had no emphysema on LDCT. Inhaler use and symptoms were more common in the "known" than the "undiagnosed" COPD group (63% vs. 33% with persistent cough [P < 0.001]; 73% vs. 33% with dyspnea [P < 0.001]). Comorbidities were common in all groups. Adjusted odds ratio (aOR) of respiratory symptoms were more significant for airflow obstruction (aOR GOLD 1 and 2, 1.57; confidence interval [CI], 1.14-2.17; aOR GOLD 3 and 4, 4.6; CI, 2.17-9.77) than emphysema (aOR mild, 1.12; CI, 0.81-1.55; aOR moderate, 1.33; CI, 0.85-2.09; aOR severe, 4.00; CI, 1.57-10.2).Conclusions: There is high burden of "undiagnosed COPD" and emphysema in LCS participants. Adding spirometry findings to the LDCT enhances identification of individuals with COPD.Clinical trial registered with www.clinicaltrials.gov (NCT02558101).

Keywords: case finding; chronic obstructive pulmonary disease; emphysema; low-dose computed tomography; lung cancer screening.

Figure 1.

Prevalence of respiratory symptoms (inclusive of those with a history of persistent cough or dyspnea during the 12 months preceding the lung health check [LHC]) in participants with a FEV₁:FVC <70% on the pre–low-dose computed tomography (LDCT), prebronchodilator spirometry, and with or without emphysema detected at LDCT. *Termed “chronic obstructive pulmonary disease” (COPD) solely on the basis of LHC spirometry. FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity.

Figure 2.

Prevalence and grade of (A) airflow obstruction and (B) emphysema by chronic obstructive pulmonary disease (COPD) group. COPD groups: “no COPD” (FEV₁:FVC ≥70%); “undiagnosed COPD” (FEV₁:FVC <70% and no reported history of COPD); and “known COPD” (FEV₁:FVC <70% and a reported history of COPD). FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity; GOLD = Global Initiative for Obstructive Lung Diseases.

Figure 3.

Prevalence of (A) reported respiratory symptoms within 12 months preceding the lung health check, (B) reported inhaler use, and (C) reported comorbidities, by chronic obstructive pulmonary disease (COPD) group. *P ≤ 0.05 and **P ≤ 0.001. COPD groups: “no COPD” (FEV₁:FVC ≥70%); “undiagnosed COPD” (FEV₁:FVC <70% and no reported history of COPD); and “known COPD” (FEV₁:FVC <70% and a reported history of COPD). FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity; ICS = inhaled corticosteroid; LABA = long-acting β-agonist; LAMA = long-acting antimuscarinic agent; LRTI = lower respiratory tract infection; SABA = short-acting β-agonist.

Figure 4.

Prevalence of reported respiratory symptoms within 12 months preceding the lung health check in those with and without emphysema by chronic obstructive pulmonary disease (COPD) group. COPD groups: “no COPD” (FEV₁:FVC ≥70%); “undiagnosed COPD” (FEV₁:FVC <70% and no reported history of COPD); and “known COPD” (FEV₁:FVC <70% and a reported history of COPD). *P ≤ 0.05. FEV₁ = forced expiratory volume in 1 second; FVC = forced vital capacity; LRTI = lower respiratory tract infection.