Timing of Onset of Persistent Critical Illness in Brazil: A Nested Secondary Analysis of the IMPACTO-MR Cohort Study

OBJECTIVE: To determine the transition point to persistent critical illness (PerCI) in Brazilian ICUs and to describe the characteristics, outcomes, and resource utilization of patients who develop PerCI. DESIGN: Multicenter cohort study. SETTING: Fifty-six adult ICUs participating in the national The Impact of Infections by Antimicrobial-Resistant Microorganisms in Patients Admitted to Adult ICUs in Brazil: Platform of Projects to Support the National Action Plan for the Prevention and Control of Antimicrobial Resistance (IMPACTO-MR) platform across public and private hospitals in Brazil. PATIENTS: Adult patients admitted from September 2019 to December 2023 to the participating ICUs. Patients younger than 18 years, ICU readmissions, and admissions from units with incomplete severity data were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We derived two predictive models-one based on antecedent characteristics and another on acute illness severity-in a training cohort. We applied both models to a test cohort, and evaluated model discrimination for in-hospital mortality daily for patients who remained in the ICU up to day 28. PerCI was defined as the ICU day at which the predictive discrimination of acute illness severity declined to match or fall below that of antecedent characteristics. A total of 75,475 adult ICU patients admitted between 2019 and 2023 were included. At admission, discrimination was higher for the acute illness model (area under the receiver operating characteristic curve AUROC 0.828) than for the antecedents characteristics model (AUROC 0.638). The predictive performance of acute characteristics declined progressively and crossed that of antecedent characteristics on ICU day 15, defining PerCI. Overall, 7960 patients (10.5%) met this definition yet accounted for 44.2% of all ICU bed-days. PerCI patients had ICU mortality of 38.2%, and in-hospital mortality of 51.2%. CONCLUSIONS: In Brazilian ICUs, the transition to PerCI occurs at 15 days, later than that reported in most prior studies. Although only one in ten patients develop PerCI, they use almost half of ICU bed-days. Further research and policy are needed to mitigate potentially modifiable contributors to prolonged critical illness.