COPD More Prevalent Than Estimated, With Mortality Linked to Aspergillosis, Review Finds

Chronic obstructive pulmonary disease (COPD) is more prevalent than previously thought and associated with a mortality rate that is likely higher than earlier estimates, a review study has found.

Invasive aspergillosis — a respiratory infection caused by molds belonging to the Aspergillus genus — may be a contributing factor to this increase in COPD mortality rates, according to the authors.

The study, “The global impact of Aspergillus infection on COPD,” was published in the journal BMC Pulmonary Medicine.

COPD is one of the most common non-transmissible diseases affecting the lungs. The disease tends to worsen over time and cause irreversible lung damage.

COPD is also considered a risk factor for invasive aspergillosis — a respiratory infection caused by molds that can be life-threatening if not identified and treated early.

“Prior estimates of the annual global incidence of IA [invasive aspergillosis] range upwards from 200,000, but difficulties in the precise diagnosis of IA in COPD patients has restrained efforts to include this group in the estimates,” the researchers wrote.

Now, investigators from the University of Manchester in the U.K. carried out a systematic literature review to obtain global and individual country estimates for the prevalence of COPD, hospitalizations related to COPD, and number of cases of invasive aspergillosis in this patient population.

The online database PubMed was used to identify studies on these topics published between January 2000 and May 2019. Data from these studies were then used to re-estimate the prevalence of COPD, hospitalizations, and invasive aspergillosis.

Each study included in the analyses had enrolled at least 50 patients. Priority was given to studies that used similar methodologies and the GOLD criteria — a well-established COPD staging tool based on patient lung function parameters.

Mild-to-severe COPD (GOLD stage 2 to 4) was estimated to affect more than 552.3 million people worldwide, or in other words, 7.39% of the world population. The highest prevalence of COPD cases among continents was found in Oceania, with an estimated prevalence of 10.86%, and Asia, with a prevalence of 8.58%.

“Given that the most recent global estimate for COPD prevalence was 251 million, now up to 300 million according to the Global Burden of Disease consortium, our estimate is much higher even excluding countries with populations under 1 million and excluding GOLD stage I data,” the investigators wrote.

A total of nearly 58 million people (10.5%) worldwide were estimated to be hospitalized due to COPD every year. From these hospitalizations, 753,073 (1.3%) to 2,272,322 (3.9%) developed invasive aspergillosis.

Estimates also indicated that 540,451 to 977,082 of hospitalized COPD patients die from invasive aspergillosis every year.

“Overall COPD mortality may be higher than estimated and IA probably contributes to many deaths,” the researchers wrote, adding that the “estimate of deaths from IA are remarkably high … and need validation with additional epidemiology studies.”

“Our study highlights the need for healthcare professionals to be aware of the possible risk of IA in their patients, and associated mortality, to identify and treat patients sooner, lowering mortality,” the team concluded. “We hope that this report will encourage further research into COPD epidemiology and the relationship between Aspergillus infection and COPD.”