Little SA, MacLeod KJ, Chalmers GW, Love JG, McSharry C, Thomson NC. Am J Med. 2002;112:446–452
Some patients with chronic asthma develop irreversible airflow obstruction. The aim was to assess whether reported duration of asthma and induced sputum cell counts were associated with pulmonary function in patients with asthma who did not smoke.
Maximal forced expiratory volume in 1 second (FEV1) was determined after a steroid trial (oral prednisolone, 30 mg/day [n = 9 patients]; or inhaled fluticasone, 2000 μg/day [n = 5]; for 2 weeks) and 2.5 mg of nebulized albuterol. Asthma history was recorded with duration from first diagnosis. All subjects were nonsmokers, or were to have stopped smoking ≥5 years previously and smoked ≤5 pack-years (n = 12). Induced sputum was obtained from 59 subjects for analysis of airway cell counts.
Maximal FEV1 was inversely associated with asthma duration (r...