Nonreversible airflow obstruction in life-long nonsmokers with moderate tosevere asthma

The aim of this longitudinal study was to assess the frequency of nonrevers ible airflow obstruction (NRAO) among adults with moderate to severe asthma , and to compare the decline of forced expiratory volume in one second (FEV 1) in asthmatics with reversible and nonreversible airflow obstruction. Ninety-mo (31 males) life-long nonsmokers dth asthma participated in a 10-y r follon-up study; mean age 37 yrs (range 18-64) and duration of asthma 16 yrs (range 2-60) at enrolment. Case history, including use of asthma medica tion, was obtained, and pulmonary function, including diffusion capacity, w as measured using standard techniques. At enrolment, all patients had typic al symptoms and reversible airflow obstruction. (NRAO) was defined as FEV1 <80% predicted and change in Delta FEV1 after 5 mg salbutamol <9% pred. A total of 21 (23%) patients (mean age at enrolment 32 yrs) fulfilled the c riteria for NRAO at the time of follow-up; current therapy nas inhaled ster oids (n=21, mean daily dose 1.5 mg), oral steroids (n=14), theophylline (n= 20), oral beta(2)-agonist (n=6) and inhaled Pt-agonist. The patients with N RAO (n=21) had a steeper decline in FEV1 than the remaining patients (n=71, reversible airflow obstruction (RAO)), mean+/-SD, 53+/-23 mL.yr(-1) and 36 +/-21 mL,yr(-1), respectively (p<0.003). Increasing degree of branchodilato r reversibility (Delta FEV1 % pred) at enrolment (p=0.002) and long-term tr eatment with oral corticosteroids (p=0.009) were associated with an increas ed risk for the presence of NRAO at follon-up. The comparison of data for N RAO and RAO patients (at follow-up) revealed no significant differences in mean values for total diffusion capacity (rr,co), diffusion constant (KCO), or total lung capacity. The findings suggest that a subgroup of asthmatics may experience very stee p rates of decline in forced expiratory volume in one second Leading to sev ere nonreversible airflow obstruction, whereas no indication was found that long-standing asthma may lead to the development of emphysema.