Here is the design of a clinical trial:

Official Title: Enhancing the Public Health Impact of Latent Tuberculosis (TB) Infection Diagnosis and Treatment: A Pragmatic Cluster Randomized Trial

Included conditions:
- Latent Tuberculosis Infection

Study Armgroups:
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'No Intervention: Program runs as per usual. Minimal interference and visits from study staff. Main study outcomes evaluated in first and last 6 months of trial. Minimal visits to collect information on costing at control sites.'}
- {'label': 'Intervention', 'type': 'ACTIVE_COMPARATOR', 'description': 'Latent Tuberculosis Infection program evaluation \\& diagnosis: In intervention health facilities the current Latent Tuberculosis Infection program will be evaluated and gaps in the Latent Tuberculosis Infection cascade of care will be identified. Gaps in the current cascade will be quantified and solution proposed that are unique to the problems identified in each site. In phase 2 of the study low cost solutions will be implemented and the Latent Tuberculosis Infection program scaled up and improved. Study outcomes are evaluated in the first and last 6 months of trial. Costing evaluations are done throughout the trial.', 'interventionNames': ['Other: Latent Tuberculosis Infection program evaluation & diagnosis']}

Interventions:
- {'type': 'OTHER', 'name': 'Latent Tuberculosis Infection program evaluation & diagnosis', 'armGroupLabels': ['Intervention']}

Primary Outcomes:
- {'measure': 'The primary outcome will be the change in the number of household contacts (HHC) initiating treatment per newly diagnosed TB index patient within 3- 4 months from index patient diagnosis, between Phase 1 and Phase 2', 'description': 'A new TB index patient will be microbiologically confirmed using AFB smear, culture, and/or molecular tests such as Xpert®MTB/RIF, depending on local protocols. A HHC will be defined as someone who slept in the same house at least one night per week, or spent more than one hour in the house at least five days per week, on average, over the preceding 3 months. The house will be defined as the dwelling, or buildings, which the family unit occupies and uses regularly. In each of the 6 month periods, the total number of index patients, the number of their contacts who were recorded in clinic documents, and the number of these HHC who initiate LTBI therapy will be collected in both the control and intervention arms. For TB index patients diagnosed towards the end of each 6-month period in most sites we will allow up to 3 or 4 additional months for the HHC to be started on LTBI treatment.', 'timeFrame': 'The primary outcome will be recorded at all health facilities for the full duration of phase 1 (6 months) and for the last 6 months of phase 2.'}

Please estimate the sample size based on the assumption: 
The variance of the random effect was set at 0.7, 1.4, and 2.8, resulting in ICCs of 0.16–0.40. Power was estimated using 500 datasets for each combination of parameters, with a significance level (alpha) of 0.05. The power to detect a significant effect was 73%-75% for an increase of 10 contacts, and over 96% for an increase of 15 contacts.
Sample size
        Twenty-four randomisation units (single health facilities or groups of health facilities) were identified, such that each unit anticipated seeing 20 index TB patients and 80 HHCs over a 6âmonth period. The anticipated number of TB patients and HHCs in each country is shown in table 1. The annual number of TB patients was obtained from pre-existing registries at each of the sites.
        
          Table 1
          
            Anticipated number of index tuberculosis patients and their household contacts at participating sites
          
          
            
              
                Country
                Number of index TB patients in 6âmonths*
                Household contacts
                Randomisation units (cluster/health facilities)
              
              
                Identifiedâ 
                With LTBIâ¡ (TST pos.)
              
            
            
              
                Canada
                125
                525
                150
                4
              
              
                Benin
                250
                1050
                540
                2
              
              
                Ghana
                150
                630
                325
                2
              
              
                Indonesia
                150
                630
                325
                8
              
              
                Vietnam
                150
                630
                325
                8
              
              
                Total
                825
                3465
                1665
                24
              
            
          
          
            
              *Approximate number based on retrospective information provided from TB registries at sites.
            
            
              â Estimated based on 4.2 contacts identified per active TB case - from systematic review.33

            
            
              â¡Estimated based on prevalence of LTBI among contacts screened: of 51.5% in low-income and middle-income countries (LMIC)28 33 and 28.1% in Canada.28

            
            
              LTBI, latent tuberculosis infection; TB, tuberculosis.
            
          
        
        For each randomisation unit, the number of HHCs expected to initiate treatment per index TB patient was generated in a simulation exercise, using a Poisson distribution with a rate that depended on the effect of the intervention, the effect of time and a normally distributed random effect for each randomisation unit. We varied the potential effect of the intervention from 5, 10, 15, 30 contacts initiating treatment per 100 index TB patients. The variance of the random effect was set at 0.7, 1.4 and 2.8. These variances resulted in approximate ICCs (intraclass correlation coefficients) of 0.16â0.40. We generated 500 datasets for each distinct combination of data generation parameters (12 scenarios).
        Using this approach we estimated power as the number of generated datasets that resulted in a statistically significant value. As shown in table 2, we will have 73%â75%âpower to detect a statistically significant (alpha=0.05) effect of the intervention if the increase in the number of HHCs initiating LTBI treatment (between phases 1 and 2), is at least 10 per 100 index TB patients. However, we will have more than 96% power to detect a significant effect of the intervention, if it results in at least 15 more HHCs initiating treatment per 100 index TB patient.
        
          Table 2
          
            Power with 24 randomisation units for various Intra-class correlations coefficient in all countries, with alpha=0.05
          
          
            
              
                Variance of the random effect
                Approximate intraclass correlation coefficients
                Difference in the change from phase 1 to phase 2 in the number of household contact starting latent tuberculosis infection treatment per index tuberculosis patient between the intervention and control arms
                Power (%)
              
            
            
              
                0.7
                0.21
                5
                28
              
              
                1.4
                0.30
                5
                32
              
              
                2.8
                0.40
                5
                26
              
              
                0.7
                0.18
                10
                74
              
              
                1.4
                0.28
                10
                76
              
              
                2.8
                0.38
                10
                73
              
              
                0.7
                0.18
                15
                96
              
              
                1.4
                0.26
                15
                97
              
              
                2.8
                0.36
                15
                97
              
              
                0.7
                0.16
                30
                100
              
              
                1.4
                0.22
                30
                100
              
              
                2.8
                0.31
                30
                100