COPD and asthma: the emergency is clear, now is the time for action
Authors: Onno CP van Schayck, Esther A Boudewijns
Journal: The Lancet Respiratory Medicine (2017)

An excellent Article1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar has been published in The Lancet Respiratory Medicine on the risk and disease estimates of chronic obstructive pulmonary disease (COPD) and asthma as part of the Global Burden of Disease Study (GBD) 2015. The Article provides a good overview of the mortality, prevalence, disability-adjusted life years (DALYs), and years lived with disability for the two most common respiratory diseases. The findings show that the prevalence of and mortality due to COPD, as well as the prevalence of asthma, increased between 1990 and 2015. However, age-standardised results indicate that this phenomenon is mainly due to an ageing population. Globally, more than 174 million people have COPD and more than 358 million people have asthma. With an ageing population, this number is expected to increase, especially for COPD. Mortality due to COPD is eight times higher than mortality due to asthma. COPD and—to a lesser extent—asthma clearly impose a substantial burden in terms of both impaired quality of life and physical, psychological, and social disability. The information presented in the report1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar is of crucial importance for policy decision making to tackle the burden of COPD and asthma. However, when looking critically at the data, we have to conclude that we are in a peculiar situation. The authors of the report were clearly compelled to make the best out of the available data. There was a need to modulate prevalence data and make assumptions to create a worldwide overview. This process is especially visible in the definitions of COPD and asthma used. Over time, definitions of COPD have differed considerably in GBD reports, causing years lived with disability to vary by a factor of two. It is concerning that after years of research, the international definition of COPD is still changing. Is it not time to make a firm decision on a globally accepted definition of COPD for the purposes of both research and care? Even more problematic is the poor consensus on the definition of asthma. For worldwide reports, we still define asthma on the basis of a reported diagnosis of asthma (with or without current wheeze). As such, risk and disease estimates are completely dependent on whether or not the patient has access to health care and whether the symptoms are presented to a physician. The authors refer to a study that compared the proportion of physician-registered asthma with screening data of the same population, indicating that only 34% of the population with symptoms and bronchial obstruction had consulted a physician.2van Schayck CP van der Heijden FMMA van den Boom G Tirimanna PRS van Herwaarden CLA Underdiagnosis of asthma: is the doctor or the patient to blame? The DIMCA project.Thorax. 2000; 55: 562-565Crossref PubMed Scopus (171) Google Scholar Consequently, underrepresentation of symptoms by patients to physicians contributes considerably to the underdiagnosis of asthma.2van Schayck CP van der Heijden FMMA van den Boom G Tirimanna PRS van Herwaarden CLA Underdiagnosis of asthma: is the doctor or the patient to blame? The DIMCA project.Thorax. 2000; 55: 562-565Crossref PubMed Scopus (171) Google Scholar The risk and disease estimates are fully dependent on the subsequent interpretation of these symptoms during diagnosis by the physician. Previously published findings have shown that 21% of patients with asthma who presented their symptoms to a physician were not diagnosed as having asthma (figure).2van Schayck CP van der Heijden FMMA van den Boom G Tirimanna PRS van Herwaarden CLA Underdiagnosis of asthma: is the doctor or the patient to blame? The DIMCA project.Thorax. 2000; 55: 562-565Crossref PubMed Scopus (171) Google Scholar There are no indications that this situation has changed since 2000 and it is therefore likely that the prevalence of asthma is considerably underestimated in the GBD report.1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar Some interesting observations can be made from the data on the distribution of DALYs lost due to COPD in the GBD report. In India, for example, the number of DALYs lost due to COPD is extremely high, whereas a report3GBD 2015 Tobacco CollaboratorsSmoking prevalence and attributable disease burden in 195 countries and territories, 1990–2015: a systematic analysis from the Global Burden of Disease Study 2015.Lancet. 2017; 389: 1885-1906Summary Full Text Full Text PDF PubMed Scopus (1046) Google Scholar published in The Lancet showed an age-standardised prevalence of smoking in India of only 17·4% (95% CI 16·8–18·2) for men and 2·8% (2·6–3·2) for women, which is considerably lower than the world average smoking prevalance of 25·0% (24·2–25·7) in men and 5·4% (5·1–5·7) in women. Consequently, the actual underlying reason for the high DALYs cannot be attributed to smoking alone. A logical explanation is the role of ambient and household air pollution, which are listed as the second and third biggest risk factors for COPD, respectively.1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar To reduce the prevalence of COPD and asthma, interventions should focus on modifiable factors. In the case of COPD, interventions aimed at smoking cessation and reducing household air pollution are the most apparent. There have been numerous initiatives to reduce smoking worldwide, resulting in a decreased prevalence between 1990 and 2015.3GBD 2015 Tobacco CollaboratorsSmoking prevalence and attributable disease burden in 195 countries and territories, 1990–2015: a systematic analysis from the Global Burden of Disease Study 2015.Lancet. 2017; 389: 1885-1906Summary Full Text Full Text PDF PubMed Scopus (1046) Google Scholar Now is the time to tackle ambient and household air pollution, which together cause more DALYs than smoking alone.1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar The use of biomass fuel is one of the greatest causes of air pollution. Nowadays, more than half of the world's population uses biomass fuel as a primary cooking source, resulting in a high burden of morbidity and mortality.4Cohen AJ Brauer M Burnett R et al.Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015.Lancet. 2017; 389: 1907-1918Summary Full Text Full Text PDF PubMed Scopus (3299) Google Scholar To reduce household air pollution, a switch to cleaner fuels would be desirable. However, this change is not always possible due to financial or logistical constraints, especially in urban slums.5Thakur M Boudewijns EA Babu GR et al.Low-smoke chulha in Indian slums: study protocol for a randomized controlled trial.BMC Public Health. 2017; 17: 454Crossref PubMed Scopus (8) Google Scholar, 6Ghergu C Sushama P Vermeulen J et al.Dealing with indoor air pollution: an ethnographic tale from urban slums in Bangalore.Int J Health S Res. 2016; 6: 348-361Google Scholar It is estimated that 1·8 billion people will still be reliant on solid biomass for cooking in 2040.7International Energy AgencyWorld energy outlook 2016. International Energy Agency, Paris2016Crossref Google Scholar Consequently, interventions should also aim to include the development of low-smoke biomass cooking stoves.5Thakur M Boudewijns EA Babu GR et al.Low-smoke chulha in Indian slums: study protocol for a randomized controlled trial.BMC Public Health. 2017; 17: 454Crossref PubMed Scopus (8) Google Scholar, 8Checkley W Pollard SL Siddharthan T et al.Managing threats to respiratory health in urban slums.Lancet Respir Med. 2016; 4: 852-854Summary Full Text Full Text PDF PubMed Scopus (20) Google Scholar The GBD study1GBD 2015 Chronic Respiratory Disease CollaboratorsGlobal, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Respir Med. 2017; (published online August 16.)http://dx.doi.org/10.1016/S2213-2600(17)30293-XGoogle Scholar reports the global burden of COPD and asthma and stresses the need for good policy making. Now it is time to make the next steps. Therefore, researchers and clinicians should respond to the call for international efforts to formulate usable definitions for asthma and COPD. It is time to tackle the enormous burden of COPD and asthma, not only by reducing smoking, but also by reducing the exposure to indoor air pollution. We declare no competing interests. Global, regional, and national deaths, prevalence, disability-adjusted life years, and years lived with disability for chronic obstructive pulmonary disease and asthma, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015Asthma was the most prevalent chronic respiratory disease worldwide in 2015, with twice the number of cases of COPD. Deaths from COPD were eight times more common than deaths from asthma. In 2015, COPD caused 2·6% of global DALYs and asthma 1·1% of global DALYs. Although there are laudable international collaborative efforts to make surveys of asthma and COPD more comparable, no consensus exists on case definitions and how to measure disease severity for population health measurements like GBD. Comparisons between countries and over time are important, as much of the chronic respiratory burden is either preventable or treatable with affordable interventions. Full-Text PDF Open Access