Proposed classification of COPD according to major risk factors

By Dr. Priyom Bose, Ph.D.Reviewed by Danielle Ellis, B.Sc.Sep 7 2022

Although there has been a significant decrease in the impact of non-communicable diseases, such as cancer and heart diseases, a global increase in morbidity and mortality linked to chronic respiratory diseases has been observed. This increment is massively related to the growing incidence of chronic obstructive pulmonary disease (COPD). In a recent The Lancet commission on COPD, scientists focussed on eliminating the disease by challenging accepted dogma and raising important questions.

Why has it been difficult to control COPD?

Throughout life, the lungs are constantly exposed to environmental factors, such as harmful pollutants. The major risk factor associated with COPD, cigarette smoking, was identified almost 50 years ago. Other factors that contributed to the public health emergency have been a failure to control the sale and intake of tobacco-based products, high exposure to environmental pollutants, and the aging of the global population.

Other underappreciated factors risk factors associated with COPD are preterm birth, low birth weight, early-life infections, and indoor and outdoor pollution. The majority of these factors are correlated to societal poverty. These risk factors mustn't be ignored. The risk factors associated with airflow limitation are plenty, and many patients are affected by more than one factor. 

The method used to diagnose COPD for decades mostly relies on post-bronchodilator spirometry, which is insensitive to pathological changes. The available guidelines for COPD mostly include simplistic disease classification, which fails to address variable pathophysiological mechanisms. This guideline recommends similar therapeutics for patients suffering from varied COPD symptoms.

Compared to other diseases with similar or lower mortality and morbidity, funds and other resources, from both public and private sectors, for COPD have been limited. This has also contributed to the limited availability of proper knowledge on the disease and inadequate therapeutics development to control disease manifestations. Acute COPD causes accelerated lung function loss and impaired quality of life. All COPD patients have been treated with antibiotics, corticosteroids, or both for the last thirty years. 

The coronavirus disease 2019 (COVID-19) pandemic highlighted the inequalities in the distribution of essential vaccines and therapeutics. For instance, while all high-income countries had a surplus of pharmaceutical and non-pharmaceutical measures, some low-income countries did not have any vaccines or essential products to contain the pandemic. Nevertheless, this barrier was reduced via a coordinated response to tackle the global crisis. A similar approach is needed to tackle the continual increase of chronic COPD. 

Recommendations to eliminate COPD

A better understanding of the risk factors associated with the incidence of COPD and the development of effective preventive measures is necessary to prevent future COPD cases. Advanced diagnostic approaches are required that are not predominantly based on spirometric airflow but instead focus on detecting early pathological changes and targeting the underlying mechanisms.

The authors strongly advocated planned collaboration to combat the disease through financial investments, regulatory reforms, and broad public policy initiatives, promoting disease prevention and treatment rather than crisis management. 

Banning cigarette smoking has also been strongly advocated to reduce COPD occurrence. More technological and financial support must be provided to tobacco industry workers to prevent an economic disaster.

The current COPD definition is associated with the presence of spirometric airflow limitation. However, this definition strongly eliminates the possibility of cure or global elimination of COPD because airflow limitation is mostly permanent in nature.

Instead, a new definition of COPD was proposed, including individuals with airflow limitation, identified via more sensitive pulmonary function tests and pathological changes detected by imaging techniques. This definition would enable the detection of pathological changes and could lead to the development of effective treatments to reverse the course of COPD.

Due to unsuitable diagnostic measures, COPD has not been classified properly, which has challenged the discovery of new methods and strategies to prevent the manifestation of the disease and devise an effective treatment. In this context, the authors recommended that COPD be classified into five groups based on different risk factors: genetics, pulmonary infection, early-life events, pollution, and tobacco smoke exposure.

Strategies to eliminate COPD

A total of six core strategies were proposed to achieve the goal of eliminating COPD. These are listed below:

• A better understanding of risk factors associated with COPD.
• Classification of COPD based on underlying causative mechanisms, genetics, respiratory infections, early-life events, and tobacco and other environmental pollutant exposures.
• Advanced diagnosis of COPD that can detect mild disease before the incidence of irreversible pathological changes. 
• Develop personalized prevention and treatment strategies for stable and exacerbating disease conditions. 
• More investment in the development of preventive and curative therapies.
• Deployment of effective public health preventive strategies, including banning cigarette smoking and maintaining clean air.