The prevalence of bronchiectasis is higher among chronic obstructive pulmonary disease (COPD) patients with predominant emphysema than those without emphysema, according to researchers.

The study, “High prevalence of bronchiectasis in emphysema-predominant COPD patients,” was conducted by a research team from the Shandong University in Jinan, China, and published in the International Journal of Chronic Obstructive Pulmonary Disease.

Bronchiectasis is classified as a comorbidity, or coexisting condition, of COPD in the Global Initiative for Chronic Obstructive Lung Disease. Although increasing studies have focused on how the coexistence of the two conditions affects exacerbation frequency, airflow limitation, prognosis, and characteristics of pathogenic microorganisms in the patients’ airways, little information is available about the relationship between bronchiectasis and the different types of COPD, which include chronic bronchitis and emphysema, a condition that causes shortness of breath due to damage to the lungs’ air sacs.

In an attempt to gain more insight about the link between these diseases, the research team investigated the prevalence of bronchiectasis in emphysema and the correlations between the two.

A total of 1,739 COPD patients were enrolled in the study. They were divided into subgroups according to two parameters: the presence of COPD with or without bronchiectasis, and the predominance of emphysema. The emphysema-predominant group was defined as having an emphysema index (EI) of at least 9.9 percent.

Of the COPD patients with measurable EI, 369 were classified as emphysema-predominant and 418 as non-emphysema-predominant. In the emphysema-predominant group, 16.5% had bronchiectasis, while 10.3% of the non-emphysema-predominant group had the condition.

Data showed that COPD patients with bronchiectasis had worse lung function, a higher EI (15% vs. 13.4%), and a higher incidence of pulmonary hypertension (6.4% vs. 2.4%), than patients without bronchiectasis. A larger proportion of patients with both COPD and bronchiectasis also had an abnormal enlargement of the right side of the heart, known as cor pulmonale (23.6 vs. 16.1%).

Moreover, researchers found that the severity of bronchiectasis increased with a higher degree of airflow limitation and emphysema.

FEV1%, a measure of lung function, and EI were found to independently predict the presence of bronchiectasis in COPD patients.

The team was able to establish a correlation between bronchiectasis and different types of COPD, with the prevalence of bronchiectasis being higher among COPD patients with predominant emphysema.

“COPD patients with concomitant bronchiectasis present poorer lung function and higher risk of complication, which should be considered a phenotype of COPD,” the researchers wrote.

“Emphysema measured by EI and FEV1% predicted are independent predictors for bronchiectasis in COPD patients, while the underlying mechanism deserves further investigation,” they said.