Maximal Airway Response in Adolescents With Long-term Asthma Remission and Persisting Airway Hypersensitivity: PC20
Fifty-three subjects who demonstrated a maximal response plateau (17 subjects in the budesonide/ remission group, 17 subjects in the placebo/remission group, and 19 subjects in the budesonide/symptomatic group) entered the second phase of study, but 6 subjects could not complete the study protocol: 3 subjects (1 in each group) due to failure to perform the test within 4 weeks of a scheduled visit because of viral respiratory infection, 2 subjects (1 in the budesonide/remission group and 1 in the budesonide/symptomatic group) due to poor compliance with inhaled budesonide (< 85%, as estimated by self-reported doses in diaries), and 1 subject in the placebo/remission group due to interruption of the test because of discomfort. The clinical characteristics of the subjects who completed the study are summarized in Table 2. No differences were observed between the three groups.
Table 3 shows the changes in PC20 according to treatment for the three groups. In neither the budes-onide group nor the placebo group were there significant differences in PC20 when the posttreatment values were compared with the baseline values. In the symptomatic group, however, inhaled budes-onide markedly increased the PC20 level (both 3-month and 6-month values compared to the baseline value, p < 0.01).
Figure 2 shows values of maximal airway response to methacholine before and after treatment for the three groups. In three subjects (one subject in the budesonide/remission group and two subjects in the placebo/remission group), it was not possible to obtain a plateau on at least one occasion. Following the inclusion of these subjects using percentage decline in FEV1 at the end of the protocol, there were no significant differences in maximal airway response when posttreatment values were compared with the baseline values in either the budesonide/remission group or the placebo/remission group: budesonide/remission group, 41.2 ± 4.7%, 39.8 ± 5.3%, and 39.5 ± 6.2% before and at 3 months and 6 months of treatment, respectively; placebo/ remission group, 41.2 ± 6.1%, 39.3 ± 8.1%, and 39.4 ± 9.8% before and at 3 months and 6 months of treatment, respectively.
Figure 2. Levels of maximal airway response before (B), and after 3 months (3M) and 6 months (6M) of treatment for the three groups (budesonide/remission group, n = 15; placebo/remission group, n = 15; budesonide/symptomatic group, n = 17). Mean and 1 SD are shown. *p < 0.01 compared to the value before treatment.
Table 2—Clinical Characteristics of the Three Treatment Groups
|Characteristics||Budesonide/Remission (n = 15)||Placebo/Remission (n = 15)||Budesonide/Symptomatic (n = 17)|
|Age, yr||14.8 ± 1.1||14.7 ± 1.3||14.7 ± 0.9|
|Male/female sex, No.||11/4||10/5||11/6|
|Serum IgE, IU/mL||295.1 (162.2-537.0)||239.9 (125.9-457.1)||234.4 (100.0-549.5)|
|Pattern of positive skin response! Baseline methacholine inhalation test||15/6/4/2/10||14/7/4/3/9||15/7/5/4/10|
|FEVj, % predicted||97.8 ± 7.8||97.5 ± 9.7||96.6 ± 11.8|
|PC20, mg/mL||6.46 (2.58-16.18)||6.43 (3.17-13.03)||7.59 (3.55-16.22)|
|Maximal response plateau, %||41.2 ± 4.7||39.4 ± 9.8||42.9 ± 3.7|
Table 3—Levels ofPC2o Before and After Treatment for the Three Groups
|Variables||Baseline||3 mo||6 mo|
|Budesonide/remission (n = 15)||6.46 (2.58-16.18)||6.31 (2.04-19.50)||7.59 (2.51-22.91)|
|Placebo/remission (n = 15)||6.43 (3.17-13.03)||7.41 (3.39-16.22)||8.13 (3.47-19.05)|
|Budesonide/symptomatic (n = 17)||7.59 (3.55-16.22)||19.50t (8.51-44.67)||26.30t (12.30-56.23)|