In patients with stable persistent asthma, can lower doses of inhaled corticosteroid medication control symptoms and maintain optimal pulmonary function as well as high doses?

BACKGROUND: In patients with chronic asthma, inflammation caused by numerous stimuli leads to recurrent symptoms, variable airflow obstruction, and bronchial hyperresponsiveness. Effective long-term control of persistent asthma requires daily administration of an anti-inflammatory agent, preferably an inhaled corticosteroid. Although inhaled steroids are generally well tolerated and safe, the lowest effective dose should be used to reduce the potential for adverse effects.¹

POPULATION STUDIED: The investigators enrolled 220 adult patients with perennial asthma from 14 outpatient clinics in Italy. Patients in this study had to be using an inhaled corticosteroid and an inhaled b2-agonist daily, had a baseline forced expiratory volume in 1 second between 50% and 90% predicted, and had symptoms present that interfered with normal daily activity during the previous 2 weeks. Patients were not included if they required systemic corticosteroids within the past month or used more than 1000 μg per day of inhaled beclomethasone dipropionate.

STUDY DESIGN AND VALIDITY: The appropriate study design was used for this article about therapy. It was a prospective randomized double-blind trial funded by the manufacturer of budesonide (available in the United States as Pulmicort). Following a 2-week observation period to establish asthma severity, all patients were treated with high-dose (800 μg twice daily) inhaled budesonide for 1 month. Patients were then randomized to receive either 400 μg (standard dose) or 100 μg (low dose) of budesonide twice daily for 6 months. The high-dose group received a placebo inhaler for use during exacerbations. The low-dose group was further divided to receive either a placebo inhaler or budesonide 200 μg 4 times daily during exacerbations. Exacerbations were identified using daily peak flow measurements to trigger the short-term use of either higher doses of inhaled budesonide or the placebo inhaler. Patients were assessed monthly and were asked to maintain a daily record of asthma symptoms, exacerbations, peak flow values, and use of b2-agonists. The patients and those assessing response to therapy were not aware of the budesonide dose. Concealed allocation to treatment group at each study site was assured through central randomization. Eighty percent of the enrolled patients completed the study, and all withdrawals were explained. Only adults (18 years and older) were studied, and the results may not be applicable to children.

OUTCOMES MEASURED: Both patient-oriented outcomes (symptom control and number of exacerbations) and disease-oriented outcomes (pulmonary function) were used to assess treatment response.

RESULTS: Of 220 enrolled patients, 213 were randomized to different doses of budesonide. The results for 209 of these (4 withdrew just after randomization) were analyzed appropriately by intention to treat. Treatment groups were well matched demographically and for confounding factors that might influence response to treatment. All patients responded well to the 4 weeks of high-dose therapy, showing progressive improvement in pulmonary function, with the majority reporting no symptoms at the end of the month. Standard-dose and low-dose budesonide controlled symptoms equally throughout the study, with no statistically significant differences reported for any symptom. Patients receiving standard-dose budesonide experienced fewer exacerbations than those receiving low-dose therapy. However, low-dose therapy patients using increased budesonide doses during exacerbations experienced significantly fewer exacerbations and fewer days of worsened symptoms than those continuing on low doses. The low-dose group using as-needed higher doses did not differ from the standard-dose group with respect to the number of days with exacerbations.