Study Examines Global Disease Burden of COPD and Asthma

Iqra Mumal, MSc avatar

by Iqra Mumal, MSc |

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A new study highlights the significant global burden of chronic obstructive pulmonary disease (COPD) and asthma, and calls for more attention in the prevention and treatment of these conditions.

The study titled “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 2015,” was published in the journal The Lancet Respiratory Medicine.

COPD and asthma are the most common respiratory diseases in the world. In 2015, COPD was ranked eighth and asthma was ranked 23rd as the leading cause of disease burden.

The Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2015 study contains yearly updates on estimates of death, prevalence, and disability-adjusted life years for more than 300 diseases and injuries from 188 countries since 1990.

Researchers set out to analyze the GBD study from 2015 and determine the estimated mortality, prevalence, and disease burden in disability-adjusted life years (DALYs) for COPD and asthma patients.

The death rates and prevalence of COPD were found to increase with age, as does the mortality of patients with asthma. So, researchers adjusted the rates of all characteristics according to the proportion of people in a given age group in the population. This is a technique that allows populations from different countries to be compared when the age profiles are quite different.

Results showed that in 2015, 3.2 million people worldwide died of COPD. There was a decrease in age-standardized death rate by 41.9% in 2015 when compared to 1990. However, there was an increase in total death by 11.6% when compared to 1990, which was attributed to the population growth and a higher proportion of the aging population.

Over the course of 25 years, from 1990 to 2015, the prevalence of COPD increased by 44.2 percent.

Concerning asthma, 0.4 million people died from the disease in 2015, which is a decrease of 26.7% compared to the deaths reported in 1990. From 1990 to 2015, the prevalence of asthma increased by 12.6%.

While asthma is far more prevalent than COPD, COPD is much deadlier with eight times more deaths than asthma. COPD caused 2.6% of worldwide DALYs, while asthma accounted for 1.1% of them.

Researchers also separated the results by socio-demographic index (SDI) — a composite measure of income per capita, mean years of education over the age of 15 years, and total fertility rate. Results showed that COPD-associated age-standardized DALY rates increased until the mid-range of the SDI, and then decreased quickly. Asthma-associated age-standardized DALY rates decreased consistently with an increase in SDI.

The team analyzed risk factors for COPD and determined that these were (from most to least significant): smoking, ambient particulate matter, household air pollution, occupational particulates, ozone, and secondhand smoke. When analyzed, these risk factors together explained 73.3 percent of COPD-associated DALYs.

For asthma, smoking and occupational asthmagens (any substance that is causally-related to the development of asthma) were the only risk factors quantified, and explained 16.5% of asthma-associated DALYs.

“COPD and asthma are important contributors to the burden of non-communicable disease. 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,” the team concluded.

“Up-to-date population information on these common diseases is key to policy decision making to improve access to and quality of existing intervention strategies,” the researchers added.

Funding for this study was provided by the Bill & Melinda Gates Foundation.