Resuscitation in paediatric septic shock using vitamin C and hydrocortisone (RESPOND): The RESPOND randomised controlled trial statistical analysis plan

Background The Resuscitation in Paediatric Septic Shock using Vitamin C and Hydrocortisone (RESPOND) trial is a multicentre randomised controlled trial exploring whether the use of hydrocortisone alone, or in combination with vitamin C, increases time alive and free of vasopressors for critically ill children. Objective To present the prespecified statistical analysis plan (SAP) for the RESPOND trial prior to finalising recruitment and locking the trial dataset. Design, setting, and participants The RESPOND trial is a three-arm, parallel group, open-label, randomised controlled trial, recruiting in paediatric intensive care units in Australia, New Zealand, India, and Brazil. The planned sample size is 384 participants. Main outcome measures The primary outcome is time alive and free of inotropes/vasopressors, censored at 7 days post-randomisation. Secondary outcomes include clinical (e.g. alive and free of multi-organ dysfunction, length of stay), safety, health economics (e.g. incremental costs, quality-adjusted life years), and long-term outcomes (measured at 6 months post-randomisation; e.g. health-related quality of life). Results and conclusions The SAP was designed by the Chief Investigators and approved by the RESPOND Steering Committee. Statistical analyses are summarised. The primary outcome will be analysed using quantile regression adjusted for stratification variables. Appropriate statistical comparisons between groups were planned and described in a way that is transparent, available to the public, verifiable, and predetermined before completion of data collection. The trial statistician, RESPOND Steering Committee members, and SAP authors remain blind to treatment allocation throughout the study. Data Safety and Monitoring Board members were provided with safety data with masked group identifiers during interim analyses. The RESPOND trial commenced recruitment in December, 2021, and aims to complete recruitment by mid-2026. Trial registration ACTRN12621000247875.