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COPD, asthma cited as important contributors to disease burden worldwide

In 2015, chronic obstructive pulmonary disease contributed to 3.2 million deaths worldwide and asthma contributed to 0.4 million deaths. These statistics demonstrate the significant impact of these respiratory diseases and a need for better policies to improve access to and quality of existing interventions for prevention and treatment, according to findings published in The Lancet Respiratory Medicine.

“Chronic respiratory diseases are among the leading causes of mortality and morbidity worldwide,” Theo Vos, MD, PhD, from the Institute of Health Metrics and Evaluation at the University of Washington, and colleagues wrote. “Of all chronic respiratory diseases, chronic obstructive pulmonary disease (COPD) and asthma are the most common.”

The researchers conducted a systematic analysis of the Global Burden of Diseases, Injuries, and Risk Factors (GBD) study to estimate mortality, prevalence and disease burden in disability-adjusted life years (DALYs) and years lived with disability (YLDs) for COPD and asthma between 1990 and 2015. They used the GBD Cause of Death Ensemble modeling tool for the analysis.

Data indicated the most common chronic respiratory disease worldwide was asthma. There were twice as many cases of asthma as there were for COPD. However, COPD-related deaths were eight-fold more common than asthma-related deaths. The number of deaths from COPD rose from 2.8 million deaths in 1990 to 3.2 million deaths in 2015, an 11.6% increase, while the number of cases increased from 121 million to 174.5 million during the same period, a 44.2% increase. Asthma-related deaths decreased by 26.2% from 0.55 million to 0.4 million between 1990 and 2015; however, asthma prevalence increased by 12.6% from 318.2 million to 358.2 million cases.

Vos and colleagues noted that while asthma and COPD can often be treated or prevented with interventions that are affordable, many individuals go undiagnosed, misdiagnosed or undertreated.

“COPD and asthma contribute substantially to the burden of non-communicable disease,” Vos said in a related press release. “Although much of the burden is either preventable or treatable with affordable interventions, these diseases have received less attention than other prominent non-communicable diseases like cardiovascular disease, cancer or diabetes. Up-to-date information on COPD and asthma is key to policy making to improve access to and quality of existing interventions.”

In 2015, the greatest disease burden for COPD was seen in Papua New Guinea, India, Lesotho and Nepal, with age-standardized COPD DALY rates higher than 2,000 per 100,000 people. The greatest burden for asthma was seen in Afghanistan, Central African Republic, Fiji, Kiribati, Lesotho, Papua New Guinea and Swaziland, with age-standardized asthma DALY rates higher than 1,200 per 100,000 people. COPD disease burden was lowest in high-income Asia Pacific, central Europe, north Africa, the Middle East, the Caribbean, western Europe and Andean Latin America, with rates below 300 per 100,000 people. For asthma, the disease burden was lowest in countries in eastern and central Europe, as well as in China, Italy and Japan, with asthma DALY rates between 100 and 200 per 100,000 people.

Smoking, air pollution, household air pollution, occupational risk (asbestos, diesel fumes, arsenic and benzene), ozone and second-hand smoke were the predominant risk factors for COPD, according to the researchers. Therefore, they advocated for the implementation of public health interventions to decrease air pollution and global smoking rates. There were less clear causes of asthma, but some factors included smoking and asthma-causing allergens in the workplace. Further research of the risk factors of COPD and asthma are needed to inform prevention methods, reduce disease burden and help define the diseases for better diagnosis, according to the researchers.

“The varied definitions of asthma and COPD around the world mean many people are not diagnosed or are incorrectly diagnosed,” Vos said. “For this reason, we need much clearer understanding of how the diseases develop to help us identify cases more conclusively. The benefits of a simpler global definition of these diseases would mean more people were diagnosed, and could access the cheap and effective treatments that can prevent these avoidable deaths.”

In an accompanying commentary, Onno van Schayck, MD, PhD, and Esther A. Boudewijns, both from Maastricht University in the Netherlands, wrote that the report by Vos and colleagues highlights the need for “good policy making” to alleviate the global burden of COPD and asthma.

“To reduce the prevalence of COPD and asthma, interventions should focus on modifiable factors,” van Schayck wrote. “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. Now is the time to tackle ambient and household air pollution, which together cause more DALYs than smoking alone. 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. 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. It is estimated that 1.8 billion people will still be reliant on solid biomass for cooking in 2040. Consequently, interventions should also aim to include the development of low-smoke biomass cooking stoves.” – by Alaina Tedesco

Disclosures: All authors report no relevant financial disclosures.