Low-intensity versus medium-intensity continuous renal replacement therapy for critically ill patients (LIMIT) trial: Protocol summary and statistical analysis plan of a randomised clinical trial

Background Severe acute kidney injury in critically ill patients may require continuous renal replacement therapy (CRRT), yet mortality remains high. A standard CRRT intensity is 20–25 mL/kg/hr, because higher doses have not improved outcomes. Excessive treatment may cause harm by removing antibiotics and other essential substances and potentially impairing renal recovery. Observational data suggest that lower-intensity CRRT may be effective, warranting a clinical trial to compare low-versus standard-intensity therapy. Objective The objective of this study was to describe the prespecified protocol and the statistical analysis plan of the low-intensity versus medium-intensity continuous renal replacement therapy for critically Ill patients (LIMIT) trial. Design, Setting, Participants, and Interventions The LIMIT trial is an investigator-initiated, multicentre, open-label, randomised clinical trial, with a target sample size of 400 participants. The trial compares low-intensity CRRT (12 mL/kg/hr) and medium-intensity CRRT (25 mL/kg/hr) in adult patients with acute kidney injury requiring CRRT in the participating intensive care units. Main outcome measures The primary outcome is a hierarchical composite of survival and time to successful liberation from RRT through day 28 from randomisation, analysed using a win-ratio. Secondary outcomes include intensive care unit mortality, hospital mortality, dialysis dependence at hospital discharge among survivors, vasopressor-free days at day 28, and ventilator-free days at day 28. Conclusion The LIMIT trial will evaluate the effect of low-intensity CRRT on mortality and time to successful liberation from RRT compared with medium-intensity CRRT in adults with acute kidney injury. Its findings may also inform future research on broader patient-centred and societal implications of CRRT intensity.