COPD, 12:113–114, 2015 ISSN: 1541-2555 print/1541-2563 online Copyright © Informa Healthcare USA, Inc. DOI: 10.3109/15412555.2015.1018510
EDITORIAL
Breathing New Perspectives into Chronic Obstructive Pulmonary Disease Martin R. Miller Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham, United Kingdom
Keywords: COPD, breathlessness, lung function testing, spirometry, symptoms Correspondence to: Martin R. Miller, Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham B15 2TT, United Kingdom. E-mail: [email protected]
For many years Chronic Obstructive Pulmonary Disease (COPD) was the poor relation to Asthma in terms of clinical focus and research effort. In recent years the table has turned with the recognition of the worldwide extent of the problem with COPD now being the 7th-leading cause of years of life lost across the globe (1). Managing COPD makes substantial demands on available health resources, and this one disease accounts for just under 1% of the total UK health budget (2). The Global Obstructive Lung Disease (GOLD) initiative was an important avenue for focussing attention on this problem. GOLD has issued two frameworks for diagnosing this condition. The first was issued in 2001 (3) and was changed in 2011 to include stratification by symptoms and exacerbations as well as by lung function but neither came with much supporting evidence. In this context it is surprising that the research community did not seek evidence to challenge whether these frameworks were the best to define and stage COPD. The first staging system was based on FEV1/FVC being below 0.7 and used cut-points of FEV1 as percent of predicted to stratify severity. This method for COPD stratification has subsequently been shown to be not as good at predicting subsequent survival in COPD when compared to cutpoints in FEV1 divided by a power of height (4), a methodology that followed the lead from Fletcher et al.'s seminal work using FEV1·ht−3 (5). The second framework, using symptoms as well as a single cut-point for FEV1, has been found to be not as good as the original one in terms of predicting survival (6). The symptoms chosen in the latest GOLD framework have included estimates of breathlessness using either a modified Medical Research Council (mMRC) dyspnoea score (7) or the COPD Assessment Test (CAT) score (8). In this issue Han et al. (9) have looked into whether mMRC or CAT gave the better grading of COPD in a large population-based study. They studied 1465 patients with post-bronchodilator FEV1/FVC LLN, with 2% of C and 7% of D having a normal FEV1/ FVC. Interestingly when using mMRC to categorise the groups the proportion of group B patients having a normal FEV1/FVC was higher at 38%. This raises a concern that over one third of those with breathlessness in Group B by mMRC criteria may in fact have a nonpulmonary cause for their dyspnoea. Because COPD is a gradually progressive disease, it was a surprise when an unexpectedly high mortality was found in Group B patients (11) from cardiovascular disease and now data from Han et al. (9) suggests this may be due to that fact that a significant proportion of group B may not, in fact, have COPD at all. The article by Han et al. (9) raises a number of important questions for future research into COPD. If the aim of the GOLD 2011 classification was to standardise how COPD patients are categorised so mortality risk and the effect of clinical interventions can be studied then the option to use either mMRC or CAT scores leads to too much variation in the defined groups. On the evidence presented by Han et al. the CAT score looks the better option. Furthermore, the GOLD classification of COPD uses the fixed ratio of FEV1/FVC
EDITORIAL
Breathing New Perspectives into Chronic Obstructive Pulmonary Disease Martin R. Miller Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham, United Kingdom
Keywords: COPD, breathlessness, lung function testing, spirometry, symptoms Correspondence to: Martin R. Miller, Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham B15 2TT, United Kingdom. E-mail: [email protected]
For many years Chronic Obstructive Pulmonary Disease (COPD) was the poor relation to Asthma in terms of clinical focus and research effort. In recent years the table has turned with the recognition of the worldwide extent of the problem with COPD now being the 7th-leading cause of years of life lost across the globe (1). Managing COPD makes substantial demands on available health resources, and this one disease accounts for just under 1% of the total UK health budget (2). The Global Obstructive Lung Disease (GOLD) initiative was an important avenue for focussing attention on this problem. GOLD has issued two frameworks for diagnosing this condition. The first was issued in 2001 (3) and was changed in 2011 to include stratification by symptoms and exacerbations as well as by lung function but neither came with much supporting evidence. In this context it is surprising that the research community did not seek evidence to challenge whether these frameworks were the best to define and stage COPD. The first staging system was based on FEV1/FVC being below 0.7 and used cut-points of FEV1 as percent of predicted to stratify severity. This method for COPD stratification has subsequently been shown to be not as good at predicting subsequent survival in COPD when compared to cutpoints in FEV1 divided by a power of height (4), a methodology that followed the lead from Fletcher et al.'s seminal work using FEV1·ht−3 (5). The second framework, using symptoms as well as a single cut-point for FEV1, has been found to be not as good as the original one in terms of predicting survival (6). The symptoms chosen in the latest GOLD framework have included estimates of breathlessness using either a modified Medical Research Council (mMRC) dyspnoea score (7) or the COPD Assessment Test (CAT) score (8). In this issue Han et al. (9) have looked into whether mMRC or CAT gave the better grading of COPD in a large population-based study. They studied 1465 patients with post-bronchodilator FEV1/FVC LLN, with 2% of C and 7% of D having a normal FEV1/ FVC. Interestingly when using mMRC to categorise the groups the proportion of group B patients having a normal FEV1/FVC was higher at 38%. This raises a concern that over one third of those with breathlessness in Group B by mMRC criteria may in fact have a nonpulmonary cause for their dyspnoea. Because COPD is a gradually progressive disease, it was a surprise when an unexpectedly high mortality was found in Group B patients (11) from cardiovascular disease and now data from Han et al. (9) suggests this may be due to that fact that a significant proportion of group B may not, in fact, have COPD at all. The article by Han et al. (9) raises a number of important questions for future research into COPD. If the aim of the GOLD 2011 classification was to standardise how COPD patients are categorised so mortality risk and the effect of clinical interventions can be studied then the option to use either mMRC or CAT scores leads to too much variation in the defined groups. On the evidence presented by Han et al. the CAT score looks the better option. Furthermore, the GOLD classification of COPD uses the fixed ratio of FEV1/FVC
