Association of Days Alive and at Home at Day 90 After Intensive Care Unit Admission With Long-term Survival and Functional Status Among Mechanically Ventilated Patients

Abstract

Many conventional end points in randomized clinical trials of interventions for critically ill patients do not account for patient-centered concerns such as time at home, physical function, and quality of life after critical illness. To establish whether days alive and at home at day 90 (DAAH90) is associated with long-term survival and functional outcomes in mechanically ventilated patients. The RECOVER prospective cohort study was conducted from February 2007 to March 2014, using data from 10 intensive care units (ICUs) in Canada. Patients were included in the baseline cohort if they were aged 16 years or older and underwent invasive mechanical ventilation for 7 or more days. The follow-up cohort analyzed here comprised RECOVER patients who were alive and had functional outcomes ascertained at 3, 6, and 12 months. Secondary data analysis occurred from July 2021 to August 2022. Composite of survival and days alive and at home at day 90 after ICU admission (DAAH90). Functional outcomes at 3, 6, and 12 months were evaluated with the Functional Independence Measure (FIM), the 6-Minute Walk Test (6MWT), the Medical Research Council (MRC) Scale for Muscle Strength, and the 36-Item Short Form Health Survey physical component summary (SF-36 PCS). Mortality was evaluated at 1 year from ICU admission. Ordinal logistic regression was used to describe the association between DAAH90 tertiles and outcomes. Cox proportional hazards regression models were used to examine the independent association of DAAH90 tertiles with mortality. The baseline cohort comprised 463 patients. Their median age was 58 years (IQR, 47-68 years), and 278 patients (60.0%) were men. In these patients, Charlson Comorbidity Index score, Acute Physiology and Chronic Health Evaluation II score, ICU intervention (eg, kidney replacement therapy or tracheostomy), and ICU length of stay were independently associated with lower DAAH90. The follow-up cohort comprised 292 patients. Their median age was 57 years (IQR, 46-65 years), and 169 patients (57.9%) were men. Among patients who survived to day 90, lower DAAH90 was associated with higher mortality at 1 year after ICU admission (tertile 1 vs tertile 3: adjusted hazard ratio [HR], 0.18 [95% CI, 0.07-0.43]; P < .001). At 3 months of follow-up, lower DAAH90 was independently associated with lower median scores on the FIM (tertile 1 vs tertile 3, 76 [IQR, 46.2-101] vs 121 [IQR, 112-124.2]; P = .04), 6MWT (tertile 1 vs tertile 3, 98 [IQR, 0-239] vs 402 [IQR, 300-494]; P < .001), MRC (tertile 1 vs tertile 3, 48 [IQR, 32-54] vs 58 [IQR, 51-60]; P < .001), and SF-36 PCS (tertile 1 vs tertile 3, 30 [IQR, 22-38] vs 37 [IQR, 31-47]; P = .001) measures. Among patients who survived to 12 months, being in tertile 3 vs tertile 1 for DAAH90 was associated with higher FIM score at 12 months (estimate, 22.4 [95% CI, 14.8-30.0]; P < .001), but this association was not present for ventilator-free days (estimate, 6.0 [95% CI, -2.2 to 14.1]; P = .15) or ICU-free days (estimate, 5.9 [95% CI, -2.1 to 13.8]; P = .15) at day 28. In this study, lower DAAH90 was associated with greater long-term mortality risk and worse functional outcomes among patients who survived to day 90. These findings suggest that the DAAH90 end point reflects long-term functional status better than standard clinical end points in ICU studies and may serve as a patient-centered end point in future clinical trials.