Independent Risk Factors Associated With Fixed Airflow Obstruction in Older Adults With Asthma

Independent risk factors associated with fixed airflow obstruction (FAO) in older adults (≥55 years of age) with asthma have been identified, according to the results of a prospective study published in the Annals of Allergy, Asthma & Immunology.

Gregory H. Bennett, DO, and colleagues evaluated participants using the Asthma Control Test (ACT) score, Asthma Quality of Life (AQLQ) score, comorbidities, spirometry measures, atopic status, and fractional exhaled nitric oxide level. Clinical characteristics and outcomes associated with FAO were then assessed.

The study (Achieving Better Control for Older Adults With Asthma; ClinicalTrials.gov identifier: NCT01979055) included 186 participants (48 men and 138 women; mean age, 66 years), 30% of whom had FAO. 

In a regression analysis, male sex, older age, African American race, and increased duration of asthma were independent risk factors associated with FAO. However, in contrast to its role in younger patients with asthma, FAO in older adults was not implicated in poorer asthma outcomes.  

Although the outcomes analysis found that FAO was associated with worsened ACT and AQLQ scores, after controlling for confounding factors, logistic regression showed no association. Furthermore, no significant association was found between FAO and exacerbations, fractional exhaled nitric oxide level, atopy, rhinitis, education level, depression, smoking, or body mass index.

There were a number of limitations to this study. The patient population was limited to the Midwestern United States, and those with a prior diagnosis of chronic obstructive pulmonary disease (COPD) and emphysema were excluded, which may have potentially excluded patients with asthma COPD overlap syndrome. In addition, baseline data were obtained at a single visit and do not reflect the variable nature of asthma, and finally, asthma severity could have been misclassified based on the criteria of asthma medication use.

The authors argued that future studies are required to further analyze patient subgroups, including the very old (older than 80 years of age) and those with asthma COPD overlap syndrome. They further noted that asthma is a complex disease and that continued isolation of relevant risk factors is essential for optimal evaluation, diagnosis, management, and counseling related to the treatment of older adults with asthma.

Reference

Bennett GH, Carpenter L, Hao W, Song P, Steinberg J, Baptist AP. Risk factors and clinical outcomes associated with fixed airflow obstruction in older adults with asthma [published online December 28, 2017]. Ann Allergy Asthma Immunol. doi:10.1016/j.anai.2017.10.004