Chest
Original ResearchAsthmaPredictors of Airway Hyperresponsiveness Differ Between Old and Young Patients With Asthma
Section snippets
Subjects
Subjects were recruited by advertising throughout The University of Sydney and from the volunteer database at the Woolcock Institute of Medical Research. Inclusion criteria were physician diagnosis of asthma plus current symptoms of asthma requiring regular treatment. Subjects were excluded if they had smoked within the last 6 months, had a smoking history ≥ 10 pack-years, had any major respiratory disease other than asthma, had a respiratory tract infection, or used oral prednisone in the
Subjects
One hundred four subjects with asthma participated in the study. Table 1 shows the characteristics of subjects in the young and old groups. The prevalence of AHR was lower in the old group (49%) than in the young group (70%, P = .03). Compared with young patients with asthma, the old patients with asthma had longer disease duration, more airflow obstruction, less severe AHR, and lower Feno. Diffusion-dependent ventilation heterogeneity (Sacin) was worse in the old group than in the young group,
Discussion
In this study of young (18-46 years) and old (≥ 50 years) adults with asthma, we found differences in the pathophysiologic determinants of AHR. The presence of significant interactions between age group and key predictor variables implied that there were significant qualitative differences between age groups in their relationship with AHR, which made it essential to analyze the two groups separately. In old patients with asthma, AHR was predicted by gas trapping (% predicted RV), Sacin, and
Acknowledgments
Author contributions: Ms Hardaker and Dr Salome had access to the data and take responsibility for the integrity of the data and the accuracy of the data analysis.
Ms Hardaker: contributed to the implementation, statistical analysis, interpretation, and writing.
Dr Downie: contributed to the design, implementation, interpretation, and writing.
Ms Kermode: contributed to the implementation, interpretation, and writing.
Dr Farah: contributed to the implementation, interpretation, and writing.
Dr Brown:
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Funding/Support: This study was funded by the National Health and Medical Research Council of Australia and the Asthma Foundation of New South Wales.
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