11 Sep

Effect of Long-term Salmeterol Therapy Compared With As-Needed Albuterol Use on Airway Hyperresponsiveness: Analysis

Effect of Long-term Salmeterol Therapy Compared With As-Needed Albuterol Use on Airway Hyperresponsiveness: AnalysisPrior to challenge testing, baseline pulmonary function levels were determined using the highest FEV1 of three efforts. Patients then inhaled five breaths of saline solution, and FEV1 was assessed 3 min after the last inhalation. Incremental concentrations of methacholine were administered in the same manner using a concentration range of 0.025 to 75.0 mg/mL. Challenges were stopped when the FEV1 from all three post-methacholine challenge spirometry assessments for a particular concentration decreased 20% from the highest post-saline solution inhalation FEV1 baseline value. The PD20 was determined by linear interpolation using software developed by PDS Research.
Analysis
Combined results are presented from two identically designed studies that were run in parallel. All analyses were performed on the intent-to-treat population using a two-sided statistical test. All p values < 0.05 were considered statistically significant. purchase birth control pills

PD20 values were log10-transformed for analysis, and mean PD20 values were expressed as the geometric mean by calculating the antilog of the log10 PD20 values. Changes from baseline for PD20 values obtained during treatment and posttreatment were expressed as doubling concentration doses of methacholine using the following formula:
[log10PD20 (treatment) – log10PD20 (baseline)]/log1(l2
Analysis of variance (ANOVA) methods were used to determine treatment effects on PD20, FEV1, and PEF measurements. Treatment group comparisons of change from baseline values for symptom scores, nighttime awakenings, and supplemental albuterol use were performed using the van Elteren test. Study withdrawal, exacerbation, and adverse event frequencies were compared by treatment group using x2 methods.
Results
Patient Demographics and Disposition A total of 202 and 206 subjects were randomized to the salmeterol and placebo treatment groups, respectively. Demographic characteristics, pulmonary function, and bronchial hyperresponsiveness to methacho-line challenge were similar between groups at screening (Table 2). A total of 87 subjects withdrew from the study after randomization.
Table 2—Patient Characteristics, Pulmonary Function at Screening, and Withdrawals from the Study

Patient Characteristics Salmeterol Group, n = 202 Placebo Group, n = 206
Sex, No.
Male 114 127
Female 88 79
Age, yr 29.3 (0.8) 28.7 (0.8)
FEV1
L 3.29 (0.5) 3.28 (0.5)
% of predicted 84.15 (0.75) 84.30 (0.72)
% reversibility 19.89 (0.60) 21.56 (0.76)
PEF, L/min
Morning 457.0 (6.3) 456.9 (6.9)
Evening 479.9 (6.2) 480.3 (7.0)
Supplemental albuterol, puffs/d 2.98 (0.18) 2.83 (0.19)
Patients with asthma a 10 yr, % 66 63
PD20, cumulative |xg 53.92 (1.10) 43.58 (1.10)
Patients withdrawn from the
study, No. (%)
Adverse event 1(< 1) 4 (2)
Failed to return 4 (2) 11 (5)
Lack of efficacy 5 (2) 8 (4)
Other 24 (12) 30 (15)

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