Determinants of Percent Predicted FEVi in Current Asthmatic Subjects


Determinants of Percent Predicted FEVi in Current Asthmatic SubjectsBy definition, persons with asthma have at least partially reversible airway obstruction. Because pulmonary function tests that measure rates of airflow, such as FEVi, are used to document this obstruction, these tests are integral to the diagnosis of asthma. Also, the FEVi has been shown to be an important tool for measuring the severity of an acute attack of asthma, the response to therapy, and the short-term prognosis of patients with asthma.
In addition to these uses of pulmonary function tests in asthma patients, the Expert Panel of the National Asthma Education Program now recommends that clinicians obtain FEVi results as part of an evaluation on routine visits “as appropriate.” Other investigators have reported that reduction of the percent predicted FEVi (% FEVi) does reflect the duration of illness, and in a study of asthmatic subjects more than 60 years of age in Tucson, we found that routine pulmonary function test results were related to the severity of wheezing in the previous year and to concomitant diagnoses, such as chronic bronchitis. In addition, we have found that asthmatic patients with severe FEVi impairment have a more favorable prognosis than patients with typical smoking-related COPD. buy ventolin inhaler

In the analyses of Tucson subjects mentioned previously, we included only selected asthmatic participants, such as the elderly. In this report, we examine the determinants of %FEVi in all 261 Tucson subjects who had asthma and completed spirometry upon enrollment in the study. Our results confirm that routine spirometry is related to the severity of current symptoms and concomitant diagnoses. In addition, %FEVi appears to decline with age, most rapidly among subjects with severe symptoms. The subjects are part of a longitudinal study of a stratified random cluster sample of white, non-Mexican-American households residing in Tucson, Arizona in 1971 to 1972. Details of selection and study of the general population sample have been reported previously.