Asthma Trial

1
Asthma Trial a double blinded, randomized,
placebo-controlled study

• Team Moser
• Jing Dong
• Yan Yan Wu
• Haipeng Yao

2

• Purpose
• The new puffer is effective or not
• Target population
• Physician-diagnosed severe asthma patients

3
Objectives and Endpoints

• Primary objective the new puffer is effective
  or not
• Primary endpoint the measurement of FEV1
• Secondary objective
• - if the puffer is effective for patients of
  different age group
• - if the puffer will reduce symptoms of
  different severity levels
  
• Secondary endpoint
• - record the numbers of Hospitalization,
  emergency visits, the use of
• rescue medication etc
• Rescue medication is allowed in this
  trial. And the of the use of rescue
• medication will be one of the measures of
  the secondary endpoint

4
Evaluation designA double blinded, randomized,
placebo-controlled study

• 1. Control
• - Intervention Group patients take the
  new puffer twice a day for 12
• weeks and record FEV1 weekly.
• - Control Group patients take
  placebo puffer twice a day for 12
• weeks and record FEV1 weekly
• 12 weeks later, all patients visit
  physician and physician diagnose if the puffer is
  effective based on the FEV1 value
• The type of design is superiority because
  our goal is that the treatment if more effective
  than placebo

5

• Randomization
• Sample size
• a0.05 ß1- power(0.8) 0.2
  (Za1.645, Zß1.28)
• Assume effective rate of the
  intervention group (Pi ) 0.4
• effective rate of the
  placebo group (Pc) 0.2
• 2N 2
  126
• Randomize
• Assign trial subject to intervention or
  control group using computer-generated
• randomization with 50-50 chance for each
  group for a total of 126 patients
• Double - Blind
• Both patients and physician are unaware of
  treatment assignment

6
Drop - outs

• complete analysis
• P effective case / N
• weighting method
• P effective case / N drop outs
• imputation method
• - LOCF (Last Observation Carry Forward)
• incomplete case analysis
• - Analyze the odds ratio of drop-outs in
  different groups
• - Use regression analysis to analyze the
  reasons of drop outs

7
Repeated Measures- Pre-post treatment on the
same observation
8
Statistical Analysis

• 1. Pi Pc 0.2 (difference in proportion)
• 2. ? gt 2 ( ? odds ratio)