How are the Stages of COPD Determined
The two most common ways to apart from traditional way of spirometry, that determines the stages of COPD are the GOLD Staging System and the BODE Index.
The Global Initiative for Chronic Obstructive Lung Disease (GOLD) is collaborating globally with health professionals and official public health organizations to highlight COPD and improve prevention and treatment of this disease.
The GOLD initiative has established guidelines for the diagnosis, management and prevention of COPD.
The GOLD criteria show that spirometry is of crucial importance in the diagnosis of COPD.
GOLD Classification of COPD
According to GOLD there are 5 stages in COPD:
0: at risk – Spirometry Normal, Chronic Symptoms (cough, sputum)
1: Beginner COPD – FEV1 / FVC <70%, FEV1> or equal to 80% of predicted values, with or without chronic symptoms (cough, sputum)
2: Moderate COPD – FEV1 / FVC <70%, FEV1 between 50% and 80% predicted values, with or without chronic symptoms (cough, sputum)
3: Severe COPD – FEV1 / FVC <70%, FEV1 between 30% and 50% predicted values, with or without chronic symptoms (cough, sputum)
4: Very severe COPD – FEV1 / FVC <70%, FEV1 <30% of predicted values or FEV1 <50% of predicted values and respiratory failure
The interest of the BODE index is that it provides additional information other than FEV1, reflecting the systemic impact of COPD. It is known that COPD is a pathology associated with systemic inflammation, dominated by an imbalance in the relationship between oxidants and antioxidants. This inflammation is thought to participate in the extra-thoracic manifestations of COPD (cachexia, osteoporosis, and cardiovascular diseases), including associated muscle abnormalities such as decreased exercise endurance. If the current conceptions of COPD are those of a systemic pathology, it appears necessary to evaluate the severity of this affection with adapted tools and no longer exclusively on a single respiratory parameter.
Limits Of the BODE Index
One of the main criticisms made of the BODE index is that it does not integrate an essential element of COPD, namely the frequency of exacerbations, which we know today is a major determinant of prognosis of these patients. According to the designers of the BODE index, repeated exacerbations must be considered as a consequence of the severity of COPD rather than as a factor causing this severity. In our opinion, this is questionable because exacerbations undoubtedly aggravate the future of COPD patients, as evidenced by the impact of exacerbations on the decline of respiratory function and the fact that better control of exacerbations improves the health status and quality of life of COPD patients.
The BODE Index: What Future?
For the moment, the interest of the BODE index is only documented as a predictor of mortality during COPD. The preliminary work reported above shows that it has many other potentialities. Recently, for example, one team mentioned the BODE index as a tool to improve the selection of COPD patients eligible for lung transplantation. It is of course necessary to wait for definitive publications, but it is tempting to imagine that the BODE index will be progressively integrated into the judgment criteria of clinical studies during the evaluation of future stable COPD therapies.