Objective: Administration of the combination of an inhaled corticosteroid (ICS) and a long-acting beta agonist (LABA) is the main treatment strategy for bronchial asthma. The ICS/LABA dosage can be reduced (stepped down) when the patient's symptoms and lung functions are well-controlled. In this study, we obtained fractional exhaled nitric oxide (FeNO) measurements to clarify whether the anti-inflammatory effect of budesonide/formoterol is shortened by step-down.
Methods: Fifty-four patients who visited the Kawasaki Medical School Hospital with newly diagnosed asthma from November 2008 to July 2010 received budesonide/formoterol for 8 weeks or more. In 29 patients, the forced expiratory volume in 1 s% predicted increased to 80% or more, and the Asthma Control Questionnaire (ACQ) score decreased to 0.5 or less within 12 weeks. These 29 patients were randomly divided into two groups: the dosage-continued group (n = 14) and the step-down group (n = 15). Then, the impact of budesonide/formoterol step-down on ACQ score, pulmonary function and FeNO level was compared between the groups.
Results: In the step-down group, the dosage was stepped down from 538 mcg/day to 331 mcg/day. In both groups, pulmonary function indicators and symptoms did not change. However, the mean FeNO level decreased significantly in the dosage-continued group (from 50.9 ppb to 45.0 ppb), and increased significantly in the step-down group (from 51.0 ppb to 65.7 ppb).
Conclusions: Clinicians should be more careful when stepping down budesonide/formoterol based solely on patients' symptoms and/or pulmonary function.