Here is the design of a clinical trial:

Official Title: Testing the Effectiveness of an Evidence-based Transdiagnostic Cognitive Behavioral Therapy Approach for Improving HIV Treatment Outcomes Among Violence-affected and Virally Unsuppressed Women in South Africa

Included conditions:
- HIV/AIDS
- Violence

Study Armgroups:
- {'label': 'CETA (Common Elements Treatment Approach)', 'type': 'EXPERIMENTAL', 'description': 'CETA is a modular, multi-problem, flexible psychotherapy approach that trains a lay provider in nine evidence-based cognitive behavioral therapy (CBT) elements so the provider can treat a variety of common problems, including violence, substance use, depression, anxiety, risky behaviors (sexual, non-adherence), and other trauma-related symptoms. Patients randomized to CETA will meet weekly with a lay provider or community health worker member of the study staff for about an hour once each week, approximately 6-12 times depending on presentation and symptom level. This treatment arm will include Short Message Service (SMS) text reminders of their HIV care appointments, similar to the active control group. As of October 12, 2022 participants can elect to have CETA delivered by telephone.', 'interventionNames': ['Behavioral: CETA', 'Other: Short Message Service (SMS) text reminders']}
- {'label': 'Active control', 'type': 'ACTIVE_COMPARATOR', 'description': 'Our comparison arm will be an active control receiving usual care for intimate partner violence. Short Message Service (SMS) text messages will be sent monthly to our control group participants to remind them of HIV care appointments.', 'interventionNames': ['Other: Short Message Service (SMS) text reminders']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'CETA', 'description': 'CETA is a modular, multi-problem, flexible psychotherapy approach that trains a lay provider in nine evidence-based CBT elements so providers can treat a variety of common problems, including violence, substance use, depression, anxiety, risky behaviors (sexual, non-adherence), and other trauma-related symptoms. Patients randomized to CETA will meet weekly with a lay provider or community health worker member of the study staff for about an hour once each week, approximately 6-12 times depending on presentation and symptom level. This treatment arm will include SMS reminders of their HIV care appointments, similar to the active control group.', 'armGroupLabels': ['CETA (Common Elements Treatment Approach)']}
- {'type': 'OTHER', 'name': 'Short Message Service (SMS) text reminders', 'description': 'Short Message Service (SMS) text reminders for upcoming appointments will be sent monthly.', 'armGroupLabels': ['Active control', 'CETA (Common Elements Treatment Approach)']}

Primary Outcomes:
- {'measure': '12 month viral suppression', 'description': 'The proportion of participants who are virally suppressed (\\<50 copies/mL) by 12 months post randomization', 'timeFrame': '12 months post randomization'}

Please estimate the sample size based on the assumption: 
With 80% power and a two-sided α=0.05, using a χ2 test for independent proportions.
Outcomes, randomisation and sample size
        We will randomise participants to CETA or control 1:1 using computer generated block randomisation (generated by the study team in Boston) with allocation generated automatically at the time of completing eligibility. Participants and study team members will not be blinded to which arm they are in. Our primary outcome is the proportion of participants who are retained and virally suppressed by 12 months postrandomisation. We will define the primary outcome to be suppression (ie, a viral load <50 copies/mL) any time up to 18 months after enrolment (to account for variation in the timing of the 12 months viral load). We will use routine clinic data collection to determine outcomes. Secondary outcomes will include: (1) viral suppression at 3 and 24 months; (2) attrition at 12 and 24 months; (3) changes in IPV, post-traumatic stress disorder, Center for Epidemiological Studies-Depression Scale (CES-D), alcohol and other substance use from baseline to 3 and 12 months and (4) cost and cost-effectiveness. The routine clinic data have been used extensively in prior research and has been found to be of high quality and fit for research purposes.39 40 Further, we have used these data approach for several other clinical trials.41 42 Details on outcomes are provided in table 2.
        
          Table 2
          
            Primary and secondary outcomes
          
          
            
              
                Outcome
                Description
              
            
            
              
                Retained and virally suppressed at 12 months
                Viral load testing is routinely done at the clinic at 6 and 12 months post-ART initiation and every 12 months thereafter. Due to the variability in when viral load testing is done, we will define the primary outcome to be suppression (ie, a viral load <50 copies/mL) any time up to 18 months. As our primary outcome includes retention, we are not able to contact patients who miss routine viral loads as this would affect attrition. Instead, we will use routine clinic data collection to determine outcomes. Missing viral loads will be a negative outcome. A combined retention/viral suppression outcome is looked at to better understand the impact of the intervention on both negative outcomes. This is because looking at suppression without considering retention rates only considers the clients retained in care and misses the large proportion of patients who drop out of HIV care
              
              
                Viral suppression at 3 and 24 months
                CETA may have some effects on suppression and retention over the first year of treatment mediated through the increased contact with patients that CETA entails. It is not clear for how long after the CETA intervention effects will be sustained. Thus, we will look at suppression at 24 months, long after CETA is complete. As our population should be monitored for suppression more frequently than every 12 months, we will also examine suppression within 3 months
              
              
                Attrition at 12 and 24 months
                Attrition (the opposite of retention) will be defined as being more than 90 days late for a study visit
              
              
                IPV, mental/behavioural health, alcohol and other substance use
                We will measure the effectiveness of CETA in reducing IPV and stress-related problems commonly associated with IPV and HIV, mental health (trauma, depression, anxiety, post-traumatic stress) and alcohol and substance use. We will also assess whether a change in these factors mediates the effectiveness of CETA on the primary outcome
              
              
                Cost and cost-effectiveness
                We will estimate the incremental cost-effectiveness of CETA vs active control in achieving the primary study outcome, retained in care and virally suppressed by 12 months, from the provider perspective. If found to be effective, a budget impact analysis will be conducted to estimate the affordability of routine implementation of the intervention at scale
              
            
          
          
            
              ART, antiretroviral therapy; CETA, Common Elements Treatment Approach; IPV, intimate partner violence.
            
          
        
        We estimate that only 40% of those who are unsuppressed (or at high risk of poor adherence) will be retained in care and virally suppressed 12 months postbaseline in the control arm.43 We believe a 20 percentage point increase in the proportion suppressed and retained between the CETA and control arms would be clinically meaningful. With 80% power and a two-sided Î±=0.05, using a Ï2 test for independent proportions our sample size required is 91 per arm (182 total).26 We increased the sample size to 400 total with a minimum of 75 women in the CETA arm who include partners (up to 100) to allow for assessment of mediation outcomes and other secondary outcomes. We are ensuring reaching our targeted enrolment by increasing the number of study sites if enrolment is less than optimal.