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The CALORIES trial: statistical analysis plan
Sheila E Harvey1, Francesca Parrott2, David A Harrison2
1Intensive Care National Audit and Research Centre, London, United Kingdom. kathy.rowan@icnarc.org.
Insights
The CALORIES trial will compare parenteral versus enteral nutrition in critically ill patients. Statistical analysis will focus on 30-day mortality to determine the optimal nutritional support route.
Area of Science:
- Critical care medicine
- Clinical nutrition
- Health economics
Background:
- The CALORIES trial is a UK-based, multicenter, randomized controlled trial (RCT).
- It compares early parenteral nutrition (PN) versus early enteral nutrition (EN) in critically ill adult patients.
- The study addresses the need for evidence on optimal nutritional support routes in intensive care.
Purpose of the Study:
- To detail the statistical analysis plan for evaluating clinical effectiveness in the CALORIES trial.
- To outline primary and secondary outcome measures and analysis methods.
- To ensure transparency by publishing the plan before data inspection.
Main Methods:
- The primary outcome is 30-day all-cause mortality.
- Analysis includes Fisher's exact test for relative risk and absolute risk reduction.
- Prespecified subgroup analyses consider age, malnutrition, illness severity, ventilation, cancer, and timing of nutritional support.
Main Results:
- Primary analysis focuses on 30-day mortality comparing parenteral and enteral nutrition.
- Secondary analyses will adjust for baseline covariates.
- Subgroup analyses will explore differential effects across patient characteristics.
Conclusions:
- A comprehensive statistical analysis plan has been developed and published for the CALORIES trial.
- This adheres to best practices for transparency and rigor in clinical trials.
- The plan guides the evaluation of early nutritional support strategies in critical care.
Background:
The CALORIES trial is a pragmatic, open, multicentre, randomised controlled trial (RCT) of the clinical effectiveness and cost-effectiveness of early nutritional support via the parenteral route compared with early nutritional support via the enteral route in unplanned admissions to adult general critical care units (CCUs) in the United Kingdom. The trial derives from the need for a large, pragmatic RCT to determine the optimal route of delivery for early nutritional support in the critically ill.
Objective:
To describe the proposed statistical analyses for the evaluation of the clinical effectiveness in the CALORIES trial.
Methods:
With the primary and secondary outcomes defined precisely and the approach to safety monitoring and data collection summarised, the planned statistical analyses, including prespecified subgroups and secondary analyses, were developed and are described.
Results:
The primary outcome is all-cause mortality at 30 days. The primary analysis will be reported as a relative risk and absolute risk reduction and tested with the Fisher exact test. Prespecified subgroup analyses will be based on age, degree of malnutrition, acute severity of illness, mechanical ventilation at admission to the CCU, presence of cancer and time from CCU admission to commencement of early nutritional support. Secondary analyses include adjustment for baseline covariates.
Conclusion:
In keeping with best trial practice, we have developed, described and published a statistical analysis plan for the CALORIES trial and are placing it in the public domain before inspecting data from the trial.
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