Statistical analysis plan for the Balanced Solution versus Saline in Intensive Care Study (BaSICS)

Lucas Petri Damiani, Alexandre Biasi Cavalcanti, Rodrigo Santos Biondi, Flávio Geraldo Rezende de Freitas, Rodrigo Cruvinel Figueiredo, Wilson José Lovato, Cristina Prata Amêndola, Ary Serpa Neto, Jorge Luiz da Rocha Paranhos, Viviane Cordeiro Veiga, Marco Antonio Vieira Guedes, Eraldo de Azevedo Lúcio, Lúcio Couto Oliveira Júnior, Thiago Costa Lisboa, Fabio Holanda Lacerda, Tamiris Abait Miranda, Israel Silva Maia, Cintia Magalhães Carvalho Grion, Flavia Ribeiro Machado, Fernando Godinho Zampieri

To report the statistical analysis plan (first version) for the Balanced Solutions versus Saline in Intensive Care Study (BaSICS). BaSICS is a multicenter factorial randomized controlled trial that will assess the effects of Plasma-Lyte 148 versus 0.9% saline as the fluid of choice in critically ill patients, as well as the effects of a slow (333mL/h) versus rapid (999mL/h) infusion speed during fluid challenges, on important patient outcomes. The fluid type will be blinded for investigators, patients and the analyses. No blinding will be possible for the infusion speed for the investigators, but all analyses will be kept blinded during the analysis procedure. BaSICS will have 90-day mortality as its primary endpoint, which will be tested using mixed-effects Cox proportional hazard models, considering sites as a random variable (frailty models) adjusted for age, organ dysfunction and admission type. Important secondary endpoints include renal replacement therapy up to 90 days, acute renal failure, organ dysfunction at days 3 and 7, and mechanical ventilation-free days within 28 days. This manuscript provides details on the first version of the statistical analysis plan for the BaSICS trial and will guide the study's analysis when follow-up is finished.