Background: The capacity of stable asthma patients to recognize the presence of air flow obstruction, treatment improvement and daily variations was studied.
Methods: Placebo and 500 micrograms of inhaled terbutaline for two consecutive days were administered to 39 patients. The subjective impressions were compared with spirometric results.
Results: Thirty patients presented obstruction of which 7 reported to be asymptomatic and 9 presented normal spirometry of which 3 reported to be symptomatic. Fifty-four percent (21) did not correctly recognize whether they improved with the medication either of the two days. Eleven patients reported improvement with placebo without significant spirometric changes. Eighteen preferred terbutaline and 5 the placebo while 16 were indifferent out of whom 7 (43%) had improved with only the bronchodilator. The FEV1 difference between the two days was > 10% in 18 patients of which this was not perceived in 10.
Conclusions: Objective controls are necessary for the evaluation and follow up of patients with stable asthma.