Experts have called for a broader definition of COPD and a rethink on its classification to help advance prevention, spur the development of novel therapies, improve its clinical management, and set the course for disease elimination.
A Lancet Commission headed by Professor Daiana Stolz , Chair of the ERS Education Council, suggests a much broader definition of COPD than spirometric airflow limitation, which essentially eliminates the possibility of cure as the pathological changes necessary to show “are almost certainly permanent”.
As such, the group has endorsed a much broader definition that includes people with airflow limitation “detected by more sensitive pulmonary function tests or pathological changes detected by imaging techniques”.
“This broader definition will enable detection of patients with earlier pathological changes, which would enhance the possibility of understanding the mechanistic pathways driving disease inception and could thus lead to the development of effective treatments to interrupt and reverse the course of COPD,” according to to the paper.
“We recognise that the risks factors leading to airflow limitation are numerous, and that many patients are affected by more than one. However, this is also true for patients with pulmonary hypertension, who can have more than one mechanism driving their disease (eg, heart failure and coexistent lung disease),” the authors noted.
“Our proposal is not perfect and, like the WHO classification of pulmonary hypertension, will require iterative refinement, but it is far more likely to yield new therapeutics than a system that relies solely on the presence of spirometric airflow limitation and a patient’s level of dyspnoea and exacerbation frequency (the extent of current attempts to classify COPD)”.
The Commission also proposed a new classification system for COPD, comprised of five different subtypes categorised by the predominant risk factors causing the disease: genetically determined disease (type 1); COPD related to early-life events (type 2); infection-related COPD (type 3); COPD related to smoking or vaping (type 4); and environmental exposure-related COPD (type 4).
“Guidelines recommend only simplistic disease classification strategies, resulting in the same therapeutic approach for patients with widely differing conditions that are almost certainly driven by variable pathophysiological mechanisms,” they said.
In a linked editorial, Respiratory Physician Professor Guy Brusselle and Professor Marc Humbert noted that “by raising awareness of the detrimental role of early-life events, infections, and air pollution (in addition to smoking and vaping) in the pathogenesis of COPD, the Commission underlines ample opportunities for prevention of COPD by protecting lung health throughout the life course”.
Also, the Commission’s classification of COPD will facilitate novel therapeutic strategies and drug development, they said.
“Indeed, the current Global Initiative for COPD (GOLD) classification of COPD severity is based on the degree of dyspnoea and the frequency of exacerbations (acute episodes of worsening symptoms). However, because symptoms are non-specific and not linked to precise underlying pathogenetic pathways, this classification system and the tendency to treat COPD as an irreversible, end-stage disease have hampered therapeutic innovation in COPD.”
Looking further ahead, prompt implementation of these measures, alongside the development of personalised prevention and treatment strategies based on a holistic assessment of COPD, investment in the development of curative and regenerative therapies, and public health strategies to ban smoking and maintain clean air, could help to “set the course to eliminate COPD”, the Commission believes.
“It is quite possible that the elimination of COPD is not achievable, much as it might be impossible to eliminate other highly complex diseases with high morbidity and mortality, such as cancer, heart disease, and diabetes,” it said.
However, the urgent action outlined by the Commission will “help drive transformational change and to assess progress along this new path towards the elimination of COPD”.