COPD mortality rates declining, but total deaths increasing

Although COPD mortality rates have declined from 1995 to 2017 in many countries, the total number of deaths attributable to COPD has increased during the past 20 years, according to new data published in the European Respiratory Journal.

“According to WHO data, in 2015, there were 175 million people living with COPD. The burden of COPD continues to be high, but the existing COPD mortality data were based on outdated statistics from a select number of high-income countries in Europe, Australia, Japan and the U.S.,” Joannie Lortet-Tieulent, PhD, a research fellow at the WHO International Agency for Research on Cancer, said in a press release. “There is a need to publish up-to-date estimates and to include mortality data from more varied regions of the world in international comparisons, as very little is known about the rate of COPD deaths in Latin America, Oceania and parts of Europe.”

Decreasing mortality rates, increasing deaths

Using COPD death count data recorded from 1995 to 2017 from the WHO mortality database, the researchers evaluated death counts according to age, sex and year. Nearly 3.36 million COPD deaths from 24 countries — six in Latin America and the Caribbean, two in North America, Asia and Oceania and 12 in Europe — were included in the analysis. Countries were included if the population exceeded 2 million people and if appropriate high-quality mortality data were available for the previous 10 years.

lthough COPD mortality rates have declined from 1995 to 2017 in many countries, the total number of deaths attributable to COPD has increased during the past 20 years, according to new data published in the European Respiratory Journal.

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The researchers calculated COPD death rates by comparing the number of COPD deaths per year against the population of each country in the same year and standardized the data using a reference population. Additionally, they restricted their analysis to people aged 50 to 84 years.

Results revealed a 12% decrease — from 68 deaths per 100,000 person-years to 60 deaths per 100,000 person-years — in the combined COPD death rate for all countries from 2000 to 2015. However, during this period, there was a 12% increase in the number of total deaths for all countries from 180,950 to 203,090 estimated total COPD deaths, according to the release.

“We think the number of deaths is rising because, in all countries, life expectancy is increasing and populations are growing. Even though the COPD mortality rate may fall over time, the decline is too small to offset the fact that each year there are more people dying due to COPD as a result of aging populations,” Lortet-Tieulent said. “The data suggest that the proportion of COPD patients who are dying early due to the disease is falling overall and that is very encouraging. It means that people may be less exposed to COPD risk factors now and that COPD is being managed more effectively.”

Differences according to sex

Overall, the researchers also found that COPD mortality has declined or remained stable among both men and women in Latin America and the Caribbean, Asia and Oceania, although increasing mortality was observed among Cuban and Australian women. In Europe, COPD mortality has also been declining among men in most countries, with the exception of stable rates in Hungary and increased rates in Czechia and Croatia. Among women, however, COPD mortality has been increasing in half of the studied countries, including in Austria, Czechia and Hungary.

Notably, data from 2016 showed that COPD mortality rates were highest in Hungary (141 deaths per 100,000 person-years) and Kyrgyzstan (135 per 100,000 person-years) among men and highest in the United States (75 per 100,000 person-years) and Hungary (71 per 100,000 person-years) among women. The lowest COPD mortality rates were seen in Italy, Costa Rica and Israel for men and in Latvia, Spain and Lithuania for women.

Despite the general trend toward lower COPD mortality rates among men and women in 18 of the 24 countries during the study period, COPD mortality rates were still twice as high in men than in women, except in the United States, New Zealand and the United Kingdom, where rates were similar for both sexes.

“Our study does not explain why COPD death rates among women increased or remained stable in some countries, but we think this trend could be linked to the rise in the uptake of smoking among women over successive generations, as smoking is an important risk factor for COPD,” Lortet-Tieulent said in the release. “In the countries where women have been smoking as much and for as long as men, such as the U.S., New Zealand and the U.K., the female COPD death rate became very similar to that of men over time.”

The researchers noted, though, that their results likely underestimate the burden of COPD mortality and that more data from low-income countries are necessary.

“COPD may result from longstanding exposure to tobacco smoking, occupational chemical substances, indoor and outdoor air pollution, with a role played by genetic susceptibility, poverty, stunting and bronchial infections such as tuberculosis. The contribution of these factors depends on the socioeconomic level of these countries,” they wrote. – by Melissa Foster

Disclosures: The authors report no relevant financial disclosures.