Pre-Chronic Obstructive Pulmonary Disease (Pre COPD)

 Pre-Chronic Obstructive Pulmonary Disease (Pre COPD)

Pre-Chronic Obstructive Pulmonary Disease (Pre COPD) is when individuals present with respiratory symptoms without spirometrically confirmed airway obstruction. This stage may eventually progress to airflow limitation consistent with a diagnosis of COPD.  Earlier there was an “at-risk” stage (GOLD stage 0), which was defined by the presence of risk factors (smoking) and symptoms (chronic cough and sputum production) in the absence of spirometric abnormalities that qualify for the diagnostic of COPD (1). Many clinicians did not prefer this category, stating that not all these individuals progresses to COPD (2). The diagnosis of chronic obstructive pulmonary disease (COPD) currently requires the demonstration of poorly reversible airflow limitation, defined as a post-bronchodilator FEV1/FVC <0.7. It is observed that patients with a history of exposure to cigarette smoke or other environmental pollutants may have substantial lung pathology and respiratory impairment even in the absence of airflow limitation, as detected by spirometry. Not all of these patients will develop airflow limitation, but many will have considerable respiratory morbidity and a comparable prognosis to those with classical, spirometrically defined COPD. Identifying individuals who will eventually develop airflow obstruction consistent with a diagnosis of COPD at a stage when FEV1/FVC value is >0.7, may enable therapeutic interventions with the potential to modify the course of disease.

There is Step-1 asthma, which is the intermittent asthma and for many years GINA guidelines proposed treatment with as needed short acting beta agonist (SABA). Later it was found out that SABA will not control underlying inflammation and most of these patients will develop persistent asthma due to airway remodeling. Now the treatment of Step-1 asthma is modified by adding anti-inflammatory agents. A similar situation can be proposed in COPD, where in if we can formulate a strategy to arrest the progression of pathology, development of overt COPD can be prevented. The clinical entity of respiratory bronchiolitis- interstitial lung disease (RB-ILD) which develop in smokers is predominantly a restrictive lung disease where FEV1/FEC will always be normal or above normal. The clinical spectrum of this disease has respiratory bronchiolitis, which is essentially small airway obstruction. Treatment suggested are avoidance of smoking and anti-inflammatory agents, preferably steroid. This is completely reversible. If not intervened at this stage, RB-ILD progresses to COPD with airflow limitation.

Pre-COPD relates to individuals of any age who have respiratory symptoms with or without structural and/or functional abnormalities, in the absence of airflow limitation, and who may develop persistent airflow limitation over time. Individuals with symptoms but without spirometrically defined obstruction compose a heterogeneous group, with some having dyspnoea and others having chronic bronchitis. Some of these individuals may never develop spirometrically defined airflow obstruction, whereas others will experience rapid lung function decline and develop overt disease (3,4) This new understanding of COPD provides novel opportunities for prevention, early diagnosis, and intervention (5).

The term pre-COPD has been recently proposed to identify individuals of any age who have respiratory symptoms with/without structural and/or functional abnormalities, in the absence of airflow limitation (FEV1/FVC > 0.7), and who may (or may not) develop persistent airflow limitation (i.e., COPD) over time (6, 7). Individuals with Pre COPD-are likely to demonstrate:

1.     Respiratory symptoms, including cough with sputum production.

2.      Physiologic abnormalities, including low-normal FEV1, reduced DLCO, and/or accelerated FEV1 decline.

3.      Radiographic abnormalities, including airway abnormalities and emphysema.

This is an important stage, which gives a window of opportunity for the clinician as well as patients, to prevent an otherwise progressive, incurable disease with much morbidity and mortality. Considering the economic burden of treating COPD on the individual, family and society, it is very important that every clinician should focus on identifying pre-COPD and intervene with appropriate steps to prevent progression to full blown COPD. Such individuals should be on regular follow up undergoing spirometric evaluation, DLCO measurements and imaging.

References

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