Study COPDGene Redefines Diagnostic Criteria of Chronic Obstructive Pulmonary Disease

Introduction

Current diagnostic criteria for chronic obstructive pulmonary disease (COPD) rely primarily on the presence of obstructive ventilatory disorder on a spirometric examination, combined with a history of tobacco product abuse and the presence of clinical symptoms. Some previous studies have suggested that a group of smokers display clinical symptoms and structural changes akin to COPD, but without the presence of obstructive disorder on a spirometric examination. Over time, these individuals may progress to a spirometrically confirmed COPD.

The goal of the COPDGene^® study analysis was to redefine the diagnostic criteria of COPD by adding key parameters that could help identify additional individuals at risk of COPD without a positive finding on spirometric examination.

Methodology

A total of 8,784 current or former smokers who participated in phase I of the COPDGene^® study met the inclusion criteria for the analysis. Four key parameters were evaluated in these patients: environmental exposure (cigarette smoking), clinical symptoms (dyspnea and/or chronic bronchitis), abnormal findings on CT (emphysema, gas trapping, and/or airway wall thickening), and abnormal spirometric findings.

Using these key parameters, patients were divided into eight groups (A–H), with the common parameter being active or former cigarette smoking. Group A, comprising patients with only the parameter of tobacco smoke exposure, served as the reference group. The primary aim of the study was to assess the risk of disease progression (a decrease in FEV₁ by > 350 ml over 5 years) and all-cause mortality.

Results

According to current classification criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD), 4,062 out of 8,784 analyzed individuals (46%) met the criteria for disease. Based on COPDGene^® diagnostic criteria, which classify individuals into groups of possible, probable, and definite COPD, an additional 3,144 individuals would be included. According to the new criteria, a total of 82% of patients would be classified into the possible, probable, or definite COPD group.

In these groups, an increased risk of disease progression and all-cause mortality was observed. A trend of increasing risk of disease progression and all-cause mortality with accumulating risk factors was noted in the groups, with the highest risk observed in group H (for progression, odds ratio [OR] 2.82; 95% confidence interval [CI] 2.18–3.66; for mortality, OR 5.18; 95% CI 4.15–6.48).

Conclusion

A substantial number of smokers with respiratory symptoms and abnormalities on CT scans do not meet spirometric diagnostic criteria for COPD. These patients are nonetheless at significant risk of spirometrically confirmed disease progression and all-cause mortality. Therefore, the scientific team that conducted the COPDGene^® study analysis proposes a redefinition of the diagnostic criteria for COPD by integrating parameters of environmental exposure, clinical symptoms, abnormal CT findings, and spirometric examination.

Expanding the diagnostic criteria could potentially capture a greater number of COPD patients who do not meet the spirometric criteria for diagnosis, providing an opportunity for current and future therapeutic interventions to successfully slow or halt the progression of the disease.

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Source: Lowe K. E., Regan E. A., Anzueto A. et al. COPDGene^® 2019: Redefining the diagnosis of chronic obstructive pulmonary disease. Chronic Obstr Pulm Dis 2019 Nov; 6 (5): 384–399, doi: 10.15326/jcopdf.6.5.2019.0149.