The risk for all-cause mortality and death related to respiratory conditions and lung cancer is significantly higher in patients with bronchiectasis compared to those without the lung disease, according to large-scale analysis conducted in Korea.
Airflow limitations and smoking were identified as the primary risk factors for bronchiectasis-related mortality.
The study, “Mortality risk and causes of death in patients with non-cystic fibrosis bronchiectasis,” was published in the journal Respiratory Research.
The number of people with bronchiectasis has been steadily increasing. In the U.S., the number of cases nearly doubled from the year 2000 to 2007.
Despite this increase, it has yet to be confirmed that bronchiectasis leads to a higher risk for early death. Many studies have reported a wide range of death rates, but did not use controls for a direct comparison, and only a few studies have examined the cause of death in patients with bronchiectasis.
Given that bronchiectasis is more common in Asia than in western countries, a team of researchers based at the Seoul National University Hospital in South Korea conducted a large-scale analysis of medical records to investigate the risk of death by any cause (all-cause mortality), and the cause of death in bronchiectasis patients, compared to a control group without the lung disease.
Selected participants were 20 years or older, and had undergone a chest computed tomography (CT) scan — a more detailed X-ray image — at the hospital between 2005 and 2016.
Basic demographic information was collected such as age, sex, and body mass index, in addition to data about comorbidities (co-existing conditions), smoking history, bacterial cultures from sputum, and lung function. Mortality and cause of death were based on the mortality data from the Korean National Statistical Office.
The team identified 18,134 participants with bronchiectasis and 90,313 control participants without lung disease.
A statistical analysis found that over an average of 5.9 years of follow-up, 1,653 (9.12%) people with bronchiectasis died, compared to 714 (0.79%) people without bronchiectasis (with an average follow-up of 5.4 years).
A calculation of person-years — a measure of incidence divided by the total time all patients were studied — showed the death rate from any cause (all-cause mortality) was 1,608.8 per 100,000 person-years in the bronchiectasis group, which was significantly higher than 133.5 per 100,000 person-years in the control group.
Smoking among bronchiectasis patients was associated with 14% of all-cause mortality, while among those in the control group, it accounted for 5.7% of deaths by any cause.
“Patients with both bronchiectasis and smoking history had the highest risk of all-cause mortality,” the researchers wrote.
A detailed statistical analysis showed that bronchiectasis was significantly linked with an increased rate in respiratory death and lung cancer-related death. Moreover, a risk factor analysis revealed that in patients with bronchiectasis, an increased risk of mortality was associated with airflow limitations (as measured by lung function tests) and a history of smoking.
Overall, the major causes of death in the bronchiectasis group were malignant cancers (31.2%), respiratory disease (30.6%), neurological conditions (9.0%), and cardiovascular disease (7.1%). In the control group, respiratory-related deaths accounted for 4.9% of total deaths.
“In conclusion, the current study showed that bronchiectasis is significantly associated with an increased risk of all-cause mortality, respiratory death, and lung cancer-related death compared with [the] control population without lung disease,” the researchers wrote.
“Physicians should pay more attention to those with airflow limitations and to smokers among bronchiectasis patients,” they said.