Asthma in the elderly: cockroach sensitization and severity of airway obstruction in elderly nonsmokers

To test the hypothesis that the presence of sensitization to indoor allergens is associated with increased severity of airway obstruction in elderly subjects with asthma.

Cohort study of subjects enrolled in a public hospital asthma clinic.

Asthma clinic in a municipal public hospital serving an indigent population in New York City.

Subjects aged > or = 60 years with asthma who were enrolled in the Bellevue Hospital Asthma Clinic. Total serum IgE and allergen-specific IgE measurements were performed in a cohort of elderly never-smokers who had asthma (45 patients) who had undergone spirometry before and after bronchodilator (BD) therapy.

The results of radioallergosorbent tests demonstrated that most subjects (ie, 60%) were sensitized to at least one allergen, with many sensitized to at least one indoor allergen. Cockroach (CR) was the most common allergen to which subjects were sensitized, with 47% displaying an elevated serum-specific IgE level. Fewer subjects were sensitized to dust mite, cat, dog, or ragweed. Subjects sensitized to CR (CR+) had greater reductions in airflow compared to subjects not sensitized to CR (CR-) [64 +/- 4.4% predicted vs 77.1 +/- 4.1% predicted FEV(1), respectively; p < 0.05]. Following BD administration, only 29% of CR+ subjects achieved a normal post-BD FEV(1) compared to 58% of CR- subjects. Lung volume measurements differed between CR+ and CR- subjects, with a greater elevation of functional residual capacity in CR+ subjects.

In a population of elderly urban patients with asthma, the presence of CR-specific serum IgE is associated with more severe asthma, as reflected by an increase in airway obstruction and hyperinflation.