Progress in understanding COPD should lead to changes in practice

Professor Nicolas Roche

France Paris —In 2023, the international GOLD document on the management of COPD was updated to reflect a better understanding of the natural history of the disease. It integrates new concepts such as trajectories, etiotypes, pre-COPD, new gradation of severity of exacerbations, as well as simplification of therapeutic algorithms.

“The understanding of COPD has changed significantly in recent years. Improving diagnostics is crucial to be able to offer patients effective treatment, drug or not, and thereby reduce the impact of the disease, explained Professor Nicolas RocheHead of the Department of Pulmonology, Cochin Hospital (AP-HP, Paris) in French edition of Medscape.

What does the evolution of the concepts covered in GOLD 2023 actually change? ^[1,2] relative to the trajectory of respiratory function?

This is a conceptual evolution, especially in relation to the trajectories and etiologies of COPD, which we therefore call etiotype. There is an emerging understanding that many cases of COPD are not only associated with accelerated deterioration of respiratory function in smokers, but are also associated with other risk factors, including those occurring in infancy or early childhood.

In the studied cohorts, the existence of two subtypes of COPD development trajectories was revealed: on the one hand, an accelerated decline in respiratory function in smokers (“classic” form) or in persons exposed to other occupational or household risk factors, and on the other. on the other hand, abnormal development of the lungs.

Finally, when looking at the COPD population as a whole, approximately half of COPD cases fall into each category: 50% are pure “declining incidence”, representing classic smoker’s COPD, while the other half represent early life risk factors.

This observation changes the way we think about prevention because it highlights the importance of not only preventing smoking and helping smokers quit, but also preventing early life exposure to secondhand smoke and reducing respiratory infections as much as possible, especially through vaccination.

It also combats prematurity and fetal malnutrition, as people with low birth weight are more likely to develop COPD in adulthood.

This also means identifying and treating asthma in children, as it may be a risk factor for developing COPD in adulthood, even if the asthma itself subsequently resolves. This is a real paradigm shift in the way we perceive COPD, both in terms of functional trajectory and etiology, and therefore in terms of the preventative measures that flow from it.

It is also possible, even likely, that respiratory function measurements will be more systematically integrated into health screenings in the future, especially screenings at key points in life, such as ages 25, 45, and 65, to detect early lung growth disorders and identify individuals at risk of developing COPD This approach aims to enhance preventive measures by eliminating all aggravating factors in these people, even if primary prevention becomes less effective when respiratory function has already deteriorated.

This brings us to the concept of pre-COPD, which is first introduced in GOLD 2023?

During this pre-COPD stage, people may exhibit symptoms or structural findings (such as emphysema or bronchial thickening seen on a CT scan).

Sometimes these abnormalities are discovered by chance during a scan done to screen for cancer, which is called an “incidental finding.”

It is also possible to detect abnormal functional manifestations of respiratory function with more in-depth testing than simple spirometry, such as pulmonary distention on plethysmography or changes in lung diffusing capacity, in the absence of bronchial obstruction (defined by an FEV1/FVC ratio of <70%). after a bronchodilator).

In situations where clinical, CT structural, or functional signs of breathing are observed before the onset of bronchial obstruction, the question arises as to what should be done.

Apart from lifestyle measures (cessation of exposure, physical activity, etc.), the question remains open. Only one study was conducted using a bronchodilator, but without proven effectiveness, given that there is no airway obstruction yet, at least of the large bronchi at this stage. A diagnosis of pre-COPD does not necessarily mean you will develop the disease, but the risk increases significantly.

Has a new definition of exacerbations been proposed?

Indeed, a new definition of exacerbations has been proposed, with a severity classification based on European consensus. She explains that an exacerbation is a deterioration that develops in less than 2 weeks, which frankly does not represent a significant improvement over the previous criteria, which required a minimum duration of 24 to 48 hours. Ultimately, it is important to remember that exacerbations are sudden worsening of symptoms. Potentially the most interesting element is the attempt to define objective and quantitative criteria for severity. However, these criteria have been criticized because they do not take into account the patient’s baseline condition, which limits their practical usefulness. Of course, this is a step forward, but it still needs confirmation and adaptation.

In a sense, do these developments in GOLD 2023 highlight the interest and indications for chest CT?

These scanners, especially those used for cancer screening, are very versatile. They can also detect signs of emphysema, thickening of the bronchial walls, and even assess sarcopenia by examining muscle thickness. With regard to COPD, indications for CT scanning are usually smokers over 45 years of age, especially in the context of cancer screening. In some cases, assessing the extent of emphysema, CT can confirm signs of decreased lung volume in severe and very stretched patients.

Increasingly, combination therapy is started at the outset of treatment, and triple therapy is now permitted immediately in patients with high eosinophil counts.

What will change in the classification of patients with COPD, moving from “A, B, C, D” to “A, B, E”?

The transition from the A, B, C, D classification to the new A, B, E classification is aimed at simplifying and placing greater emphasis on exacerbations.

Group A refers to patients with mild symptoms who require a single bronchodilator. Group B refers to patients with symptoms but no risk of exacerbation or hospitalization who benefit from dual bronchodilation. Group E includes patients at risk of exacerbation who are receiving dual bronchodilation and may require triple therapy if eosinophilia is greater than 300/mm.³.

Thus, exacerbations are necessarily highlighted, and disease-related disability remains an important point of attention in the absence of exacerbations.

Over the years, we have moved from a progressive approach, in which treatments were added gradually, to a more active strategy in which dual bronchodilation or even triple therapy can be started immediately in certain situations.

Thus, even patients with mild symptoms can be treated with long-acting bronchodilators from the outset. Indeed, by questioning them carefully, we often discover hidden symptoms.

Thus, if we follow GOLD 2023, multitherapy is increasingly being initiated from the start of treatment, and triple therapy is now permitted immediately in patients with exacerbation and high eosinophil counts.

This evolution of therapeutic proposals also reflects a better understanding of the disease. Although this may result in additional costs, such decisions are often justified by the potential benefits to patients and the minimization of long-term complications.