Skip to main content
. 2016 Jul 15;194(2):147–155. doi: 10.1164/rccm.201512-2544CP

Table 2.

Selected Strategies to Enhance Clinical Trial Efficiency

Strategy Definition Why This Strategy Improves Trial Efficiency Examples
Prognostic enrichment Identifying and focusing on high-risk patients Studying patients with a high event rate increases the statistical power to detect a given level of relative risk reduction. Norepinephrine dosage in septic shock (57)
PaO2/FiO2 ratio in ARDS (8, 58)
APACHE II score in septic shock (42)
Predictive enrichment Identifying and focusing on patients who are more likely to respond to the therapy being studied Biologic markers related to a therapy’s mechanism of action can be used to identify likely responders. Response to corticotropin test for corticosteroids in septic shock (59)
IL-6 level for monoclonal anti–tumor necrosis factor in sepsis (50)
PaO2/FiO2 ratio for neuromuscular blockade in ARDS (8)
Direct lung injury for surfactant in ARDS (60)
PaO2/FiO2 ratio for prone positioning in ARDS (58)
Vitamin D level for vitamin D replacement in critically ill patients (61)
Plasma cell–free hemoglobin for acetaminophen in severe sepsis (62)
C-reactive protein level for corticosteroids in community-acquired pneumonia (51)
Adaptive randomization Adjust trial enrollment on the basis of prespecified decision rules and early results of the trial Randomization is adapted in order to answer trial question with the fewest people, minimizing the risk of harm and ensuring adequate power. Anti-PDL1 in septic shock (53)
Risk-based subgroup analysis Determine average treatment effect by quantile of baseline risk This strategy helps clarify the expected benefit of treatment for patients on the basis of baseline risk, improving the application of clinical trial results to bedside practice. Activated protein C in severe sepsis (63)
Pulmonary artery catheters in critically ill patients (64)
Route of enteral nutrition in critically ill patients (65)
Protocol-based early goal-directed therapy in sepsis shock (66)

Definition of abbreviations: anti-PDL1 = antibody against programmed death-ligand 1; APACHE = Acute Physiology and Chronic Health Evaluation; ARDS = acute respiratory distress syndrome.