A. Fumigatus Fungus Linked to Worse Respiratory Quality of Life in People with CF, Study Finds

The presence of the fungus Aspergillus fumigatus is linked to lower respiratory-related quality of life in people with cystic fibrosis (CF), a study has found.

The study,  “The presence of Aspergillus fumigatus is associated with worse respiratory quality of life in cystic fibrosis,” was published in the Journal of Cystic Fibrosis.

A. fumigatus is a potentially harmful fungus that is widespread in the environment and that most people probably inhale on a nearly daily basis. This is not usually a problem, but it can lead to infections in people whose immune systems are compromised or who have respiratory issues.

In people with CF, A. fumigatus is known to cause allergic bronchopulmonary aspergillosis — an allergic reaction to the fungus. However, it is not clear how this fungus can affect the health of those with the condition in the absence of this allergic response.

To explore this, researchers from the University of Pennsylvania collected samples of sputum from CF patients and cultured them in the lab to look for the fungus.

They found it in 21 (10.3%) participants, while 161 showed no evidence of A. fumigatus. Thirty-seven (18%) individuals had a history of infection by A. fumigatus during the two-year period before enrolling the study; of these, 11 (5.3%) had recurrent A. fumigatus infections.

Candida species was the most common fungus detected in 57.8% of the study participants.

The team compared patients with and without A. fumigatus to look for differences that might be attributable to the presence of the fungus.

The two groups were similar in terms of demographic features such as age (mean of about 30 years old), sex (about half were female), and race (more than 90% white), as well as for clinical characteristics usch as body mass index and forced expiratory volume (a measurement of lung function).

The latter finding runs contrary to some previous studies that suggested that the presence of the fungus was associated with worse disease severity. Additional research with more participants will likely be needed to clarify whether any such relationship exists.

Further analysis showed that individuals who were positive for A. fumigatus were significantly more likely to take inhaled corticosteroids than those without evidence of the fungus (100% versus 75.8%). This association has also been reported in previous studies, although the reason for it is not fully clear and may be an avenue for future investigation.

The fungus-affected group also had significantly lower scores (49.2 vs. 60.9) on the respiratory domain of the Cystic Fibrosis Questionnaire-Revised — a measurement of respiratory-related quality of life, compared with those without the fungus. This association held constant after the team used statistical models to account for clinically relevant features including age, sex, and lung function.

“Although our analysis is cross-sectional and cannot inform causality [cause-and-effect relationships] or changes in health over time, these data suggest that [A. fumigatus] isolation may be associated with a perception of overall poorer respiratory health independent of other indicators of illness severity,” the researchers wrote, adding that “these data suggest a relationship which warrants further investigation.”