Duration of asthma and physiologic outcomes in elderly nonsmokers

Airway and alveolar inflammation have been described in asthma. Prolonged i nflammation may lead to airway remodeling, which can result in physiologic abnormalities. Elderly lifetime nonsmokers are an ideal population in which to examine the consequences of longstanding asthma. To test the hypothesis that airflow limitation and hyperinflation are associated with the duratio n of asthma, we evaluated airflow and lung volumes in a cohort of elderly a sthmatic individuals. All subjects were > 60 yr of age and were lifetime no nsmokers (n = 75). Patients with asthma of long duration (LDA; n = 38) had asthma for greater than or equal to 26 yr (median = 40.0 yr); patients with asthma of short duration (SDA; n = 37) had asthma for < 26 yr (median = 9 yr). Patients with LDA had a significantly lower FEV1% predicted than did t hose with SDA (59.5 +/- 2.6% versus 73.8 +/- 3.1% [mean +/- SEM], respectiv ely; p < 0.007). Regression analysis demonstrated that duration of asthma w as inversely associated with FEV1% predicted (r = 0.264 p < 0.03). After br onchodilator administration, the patients with LDA continued to show airflo w obstruction (FEV1% predicted = 65.4 +/- 2.9). Only 18% of patients with L DA attained a normal postbronchodilator FEV1, whereas 50% of those with SDA were able to do so (p < 0.003). The FRC% predicted was significantly highe r in subjects with LDA than in those with SDA (142.9 +/- 5.6 versus 124.1 /- 4.4 respectively, p < 0.01). Multiple regression analysis revealed an as sociation between FRC and duration of asthma that was independent of the de gree of airflow limitation. These data suggest that the duration of asthma is associated with the degree of airflow limitation and hyperinflation. Mor eover, these abnormalities can become irreversible over time, and may refle ct distal airway and/or parenchymal changes as well as proximal airway remo deling.