Rationale and design of the Early Chronic Obstructive Pulmonary Disease (ECOPD) study in Guangdong, China: a prospective observational cohort study

Background

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease and its clinically relevant subtypes are not well understood. Which clinical characteristics are more likely to be present among individuals who develop COPD remains to be studied in depth. Therefore, we designed a prospective observational cohort study, entitled the Early Chronic Obstructive Pulmonary Disease (ECOPD) study, to fill this evidence gap. The ECOPD study has four specific aims: (I) identification of characteristics, parameters, and biomarkers that may predict the development of airflow obstruction and annual decline in lung function with normal spirometry; (II) identification of clinically relevant early COPD subtypes; (III) identification of characteristics, parameters, and biomarkers that may predict disease progression in these early COPD subtypes; (IV) development and validation of machine learning models to predict development of airflow obstruction and disease progression.

Methods

We will recruit approximately 2,000 participants aged 40–80 years, including approximately 1,000 with COPD [post-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.7] and approximately 1,000 without COPD, using a population-based survey for COPD. We will assess all participants using standard respiratory epidemiological questionnaires, pulmonary function tests [pre-bronchodilator and post-bronchodilator spirometry, and impulse oscillometry (IOS)], health outcomes [modified British Medical Research Council (mMRC) dyspnea scale, COPD assessment test (CAT), COPD clinical questionnaire (CCQ)], inspiratory and expiratory chest computed tomography (CT), and biomarker measurements (blood and urine), as well as satellite remote sensing pollutant exposure measures. Subgroup will additionally complete induced sputum, exercise capacity tests [6-minute walk test (6MWT) and cardiopulmonary exercise testing (CPET)] and home monitoring/personal sampling as pollutant exposure measures. Study procedures will be performed at baseline and every 1 year thereafter.

Discussion

The ECOPD study will provide insight into many aspects of early COPD and improve our understanding of COPD development, which may facilitate therapeutic interventions with the potential to modify the course of disease.

Trial Registration

Chinese Clinical Trial Registry, ChiCTR1900024643. Registered on 19 July, 2019.

A Genome-Wide Association Study in Early COPD: Identification of One Major Susceptibility Loci

Background

Identifying the genetic basis of airflow limitation is one of the most interesting issues for understanding chronic obstructive pulmonary disease (COPD) pathophysiology. Several studies have shown that some genetic variants associated with COPD have been identified in genome-wide association study (GWAS), especially in patients with moderate to severe COPD; genetic susceptibility for airflow limitation in the early COPD phase has not been widely studied.

Objective

We investigated the genetic variants in early COPD.

Methods

The present study analyzed Gene-environment interaction and phenotype (GENIE) cohort that included participants who received health screening examination. The association between single nucleotide polymorphism (SNP) and susceptibility to early COPD (FEV1 predicted ≥50% and FEV1/FVC <0.7) was tested.

Results

A total of 130 patients with early COPD and 3478 controls (1700 ever smokers and 1778 never smokers) were recruited. When compared with the total controls, certain SNPs (rs2818103, rs875033, rs9354627, rs34552148) on chromosome 6 were included at the top of our list (p= 5.6 × 10–7 ~9.6 × 10–6) although they did not reach genome-wide significance. When compared with the never smoker controls, two SNPs (rs2857210, rs2621419) of the HLA-DQB2 gene class were persistently associated with susceptibility to early COPD.

Conclusion

Certain SNPs located on chromosome 6 or the HLA-DQB2 gene were the top-scoring SNPs for the association with susceptibility to early COPD in the Korean GENIE cohort.

Body plethysmography in chronic obstructive pulmonary disease patients: A cross-sectional study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death in the world, for which smoking is a common cause. It is preferable to diagnose COPD at an earlier stage and to assess its progression so that mortality and morbidity of the disease could be reduced. Hence, we conducted this study to assess parameters of body plethysmography in Indian population where the data are lacking and to assess whether the use of body plethysmography can detect COPD earlier.

SUBJECTS AND METHODS

The study was approved by the Ethics Committee at B. J Government Medical College, Pune. In this comparative randomized cross-sectional study, healthy control subjects (CN), smokers without COPD diagnosis (SM) who were smoking for more than 5 pack-years and smokers with COPD who were further classified depending upon GOLD criteria as mild COPD (C1), moderate COPD (C2), and severe COPD (C3) (n = 30 each group) were considered. All the participants were males who gave written informed consent. Subject underwent routine spirometry (FEV1, FVC, FEV1/FVC, PEFR, and FEF25-75%) along with body plethysmography where sGaweff, sGawtot, residual volume (RV), total lung capacity (TLC), and inspiratory capacity (IC) were recorded.

STATISTICAL ANALYSIS

The differences in lung function were compared between healthy controls and smokers and also between the three groups of COPD severity (GOLD guidelines) employing univariate analysis of variance and Bonferroni's post hoc test.

RESULTS

Spirometry could not differentiate between smokers without COPD and healthy controls. However, three parameters on body plethysmography (IC, sGawtot, and sGaweff) were sensitive enough to detect differences between smokers without COPD and healthy controls.

CONCLUSION

Using body plethysmography, the vexed question troubling the clinician, which of the smokers progress to COPD and who do not before they develop irreversible changes can perhaps be answered if further large-scale multicenter studies and long-term follow-up studies confirm the findings in this study.