Here is the design of a clinical trial:

Official Title: Effectiveness of Custom-made Foot Orthoses in Patients With Systemic Lupus Erythematous

Included conditions:
- Lupus Erythematosus, Systemic
- Foot Orthoses
- Musculoskeletal Pain

Study Armgroups:
- {'label': 'Custom-made foot orthoses', 'type': 'EXPERIMENTAL', 'interventionNames': ['Device: Custom-Made Foot Orthoses']}
- {'label': 'Control Group', 'type': 'PLACEBO_COMPARATOR', 'interventionNames': ['Device: Placebo']}

Interventions:
- {'type': 'DEVICE', 'name': 'Custom-Made Foot Orthoses', 'description': 'The foot orthoses were custom made using phenolic foam molds of the feet. They consisted of a polypropylene layer of 2 mm from heel to just proximal to the metatarsal heads, an upper sheet of 30 Shore A polyethylene foam.', 'armGroupLabels': ['Custom-made foot orthoses']}
- {'type': 'DEVICE', 'name': 'Placebo', 'description': 'The insole made using phenolic foam molds of the feet. They consisted of an upper sheet of 30 Shore A polyethylene foam.', 'armGroupLabels': ['Control Group']}

Primary Outcomes:
- {'measure': '11-point Numeric Pain Rating Scale', 'description': 'With a range of 0 = no pain to 10 = pain as bad as it can be.', 'timeFrame': '1 minute'}
- {'measure': 'SF- 12 Quality of Life', 'description': 'To describe the relationships among functional health status measures. This has values between 0 and 100, with higher values corresponding to lower quality of life.', 'timeFrame': '10 minutes'}
- {'measure': 'Foot Function', 'description': 'Foot Function Index', 'timeFrame': '5 minutes'}
- {'measure': 'Foot Disability', 'description': 'Manchester Foot Pain and Disability Index', 'timeFrame': '5 minutes'}

Please estimate the sample size based on the assumption: 
Type I error (α) is 0.05 (z(α/2) = 1.96), Type II error (β) is 0.20 (z_β = 0.84), and the dropout rate is approximately 22%.
Sample size
        The minimum sample size was calculated using the following formula to compare mean values between populations:
        
          
            
              
                
                  n
                  =
                  (
                  2
                  s
                  â§
                  2
                  (
                  Î±
                  
                    /
                  
                  2
                  )
                  +
                  z
                  _
                  Î²
                  )
                  )
                  
                    /
                  
                  d
                  â§
                  2
                  ,
                
              
            
          
        
        where s2 is the sample variance, Î± is the type I error, Î² is the type II error and d is the minimum difference to be detected. According to a previous study where the effect of foot orthoses on foot pain was investigated on patients with rheumatoid arthritis,10 the variance of the Visual Analogue Scale for pain is equal to 400, and the difference found is 16â³. Therefore, the following result was obtained:
        
          
            
              
                
                  n
                  =
                  (
                  2
                  s
                  â§
                  2
                  (
                  
                    z
                    (
                  
                  
                    Î±
                  
                  
                    /
                  
                  2
                  )
                  +
                  z
                  _
                  
                    Î²
                  
                  )
                  )
                  
                    /
                  
                  d
                  â§
                  2
                  =
                  
                    ã
                  
                  2
                  â
                  400
                  â
                  (
                  1.96
                  +
                  0.84
                  )
                  
                    ã
                  
                  
                  â§
                  2
                  
                    /
                  
                  16
                  â§
                  2
                  =
                  24.525
                
              
            
          
        
        Thus, at least 25 people will be needed in each group to compare the mean values. In this study, 60 patients will be initially recruited, with 30 in each group, in consideration of possible losses similar to previous studies (about 22%).10