Here is the design of a clinical trial:

Official Title: Re-EValuating the Inhibition of Stress Erosions: Prophylaxis Against Gastrointestinal Bleeding in the Critically Ill (The REVISE) Trial

Included conditions:
- Gastrointestinal Hemorrhage (Clinically Important, Upper)

Study Armgroups:
- {'label': 'Placebo (0.9% saline)', 'type': 'PLACEBO_COMPARATOR', 'description': 'Withholding Stress ulcer prophylaxis (intravenous 0.9% saline as placebo)', 'interventionNames': ['Drug: Placebo (0.9% saline)']}
- {'label': 'Stress Ulcer Prophylaxis (Pantoprazole)', 'type': 'ACTIVE_COMPARATOR', 'description': 'pantoprazole 40mg powder for injection reconstituted with 0.9% saline', 'interventionNames': ['Drug: Pantoprazole']}

Interventions:
- {'type': 'DRUG', 'name': 'Placebo (0.9% saline)', 'description': 'normal saline', 'armGroupLabels': ['Placebo (0.9% saline)'], 'otherNames': ['normal saline; NaCl 0.9%']}
- {'type': 'DRUG', 'name': 'Pantoprazole', 'description': '40 mg powder for injection reconstituted with 0.9% saline', 'armGroupLabels': ['Stress Ulcer Prophylaxis (Pantoprazole)'], 'otherNames': ['Protonix']}

Primary Outcomes:
- {'measure': 'Rate of clinically important upper gastro-intestinal bleeding', 'description': 'Clinically important upper GI bleeding requires the presence of overt GI bleeding which is defined as one of the following;\n\n* Hematemesis\n* Overt nasogastric bleeding\n* Melena\n* Hematochezia\n\nPLUS (in the absence of another cause), at least one of the following in the 24 hours following overt GI bleeding:\n\n* Haemodynamic change defined as a spontaneous decrease in invasively monitored mean arterial pressure or non-invasive systolic or diastolic blood pressure of 20 mmHg or more or an orthostatic increase in pulse rate of 20 beats/minute and a decrease in systolic blood pressure of 10 mmHg, with or without vasopressor initiation, or increase\n* Vasopressor initiation\n* A decrease in haemoglobin of ≥ 20 g/l in a 24-hour period or less,\n* Transfusion of ≥2 units of packed red blood cells within 24 hours of bleeding to maintain stable haemoglobin or haemodynamics, or\n* Need for therapeutic intervention (e.g. angiography, surgery or endoscopic treatment of bleeding).', 'timeFrame': '90 days (In ICU or resulting in ICU readmission, censored at 90 days after randomization)'}
- {'measure': 'Primary Safety Outcome: 90 Day Mortality', 'description': 'Mortality status at day 90 post randomization', 'timeFrame': '90 days post randomization'}

Please estimate the sample size based on the assumption: 
The study targets 85% power for detecting clinically important reductions in GI bleeding and at least 70% power for detecting effects on 90-day mortality. The sample size accounts for feasible enrollment over 4 years, including non-compliance and loss to follow-up.
Sample size
        The sample size of 4800 patients was chosen on the basis of plausible baseline risks of GI bleeding, plausible RR reductions, a target of 85% power and feasible enrolment. The best estimate of the GI bleeding event rate in the placebo arm ranging from 3% to 6% is based on the following: an international period-prevalence study (2.6%; 95% CI 1.6 to 3.6)1; the REVISE Pilot trial (placebo 6.1%; 95% CI 2.1 to 16.5)12; and the SUPICU trial placebo rate of 4.2%.3 The RR associated with pantoprazole was 0.6 in the SUPICU trial. Table 2 highlights sample size considerations for clinically important upper GI bleeding. The table presents combinations of RR reductions ranging from 30% to 50%, and baseline risks between 3% and 6% for which we will achieve 85% power. With a baseline risk of 3% and an RR reduction of 50%, the absolute benefit will be a 1.5% difference. Other highlighted cells correspond to absolute risk reduction of greater than 1.5%. In summary, across the range of plausible baseline risks, 4800 patients will provide at least 85% power to detect effects of pantoprazole as large as, or greater than, the smallest clinically important reduction in GI bleeding.
        
          Table 2
          
            Sample size with respect to clinically important bleeding outcome
          
          
            
              
                
                True underlying relative risk (PPI vs placebo)
              
              
                0.7
                0.6
                0.5
              
            
            
              
                
Event rate in placebo group

                
3%

                47.1%
                74.6%
                92.6%
              
              
                
4%

                60.1%
                86.6%
                97.8%
              
              
                
5%

                70.7%
                93.4%
                99.4%
              
              
                
6%

                79.1%
                96.9%
                99.9%
              
            
          
          
            
              This table highlights consideration for clinically important gastrointestinal (GI) bleeding. It presents combinations of relative risk reductions ranging from 30% to 50%, and baseline risks between 3% and 6% for which we will achieve 85% power. With a baseline risk of 3% and a relative risk reduction of 50%, the absolute benefit of will be a 1.5% difference. Other highlighted cells correspond to absolute risk reduction of greater than 1.5%. In summary, across the range of plausible baseline risks in the shaded boxes, 4800 patients will provide at least 85% power to detect effects of pantoprazole as large as, or greater than, this small important reduction in clinically important GI bleeding. This sample size reflects feasible enrolment in an acceptable 4-year time frame, accounting for any non-compliance or loss to follow-up, in the context of hybrid serial funding for Re-Evaluating the Inhibition of Stress Erosions.
            
            
              PPI, proton pump inhibitor.
            
          
        
        
Table 3 highlights sample size implications for 90-day mortality. The estimates of RR are informed by SUPICU in which the upper confidence limit around the increased mortality in the high-risk group (using the illness severity metric of the Simplified Acute Physiology Score (SAPS) II>53) included a value of 1.30. Among the first 25% of patients enrolled, the mortality rate was 44% across both groups in the comparable high risk of death group of concern (using the illness severity metric of the Acute Physiology and Chronic Health Evaluation (APACHE) II score>25). Our power calculations are based on the estimated 40% of REVISE patients who will fall in the high-risk group (~1920 patients). The table presents combinations of RRs ranging from 1.1 to 1.3, and baseline risks between 4% and 38%, demonstrating power of >70% for combinations of higher levels of baseline risk and RR increase. The RR of 1.13 is the point estimate in patients with high illness severity in SUPICU.3 In summary, across the range of higher baseline risks, 4800 patients will provide at least 70% power to detect effects of pantoprazole at levels that would likely preclude use of pantoprazole in patients at higher risk of death.
        
          Table 3
          
            Sample size with respect to 90-day mortality
          
          
            
              
                
                True underlying relative risk (PPI vs placebo)
              
              
                1.1
                1.13
                1.2
                1.3
              
            
            
              
                
Event rate in placebo group

                
38%

                38.0%
                57.9%
                91.5%
                99.9%
              
              
                
40%

                40.9%
                61.7%
                93.7%
                >99.9%
              
              
                
42%

                43.9%
                65.6%
                95.5%
                >99.9%
              
              
                
44%

                47.1%
                69.4%
                96.9%
                >99.9%
              
            
          
          
            
              This table highlights sample size implications for 90-day mortality. The estimates of relative risk are informed by Stress Ulcer Prevention in the ICU (SUPICU) in which the upper confidence limit around the increased mortality in the high-risk group (SAPS II>53) included a value of 1.30. Among the first 25% of patients enrolled, the mortality rate was 44% across both groups in the comparable high-risk of death group of concern (APACHE II score>25). Our power calculations are based on the 40% of REVISE patients who will fall in the high-risk group (1920 patients). The table presents combinations of relative risks ranging from 1.1 to 1.3, and baseline risks between 38% and 44%, showing power of >70% for combinations of higher levels of baseline risk and relative risk increase. The relative risk of 1.13 is the observed point estimate in patients with high illness severity in the SUPICU Trial. In summary, across the range of higher baseline risks, 4800 patients will provide at least 70% power to detect effects of pantoprazole at levels that would preclude use of the drug in patients with high illness severityâthose at higher risk of death.
            
            
              APACHE, Acute Physiology and Chronic Health Evaluation; PPI, proton pump inhibitor; SAPS, Simplified Acute Physiology Score;