By Betty Tran, MD, MSc, Editor

SYNOPSIS: The authors of this nested cohort study within a randomized, controlled trial of ICU survivors requiring > 48 hours of mechanical ventilation found that pre-existing comorbidity was the main determinant of long-term health-related quality of life.

SOURCE: Griffith DM, et al. Determinants of health-related quality of life after ICU: Importance of patient demographics, previously comorbidity, and severity of illness. Crit Care Med 2018 Jan 2. doi: 10.1097/CCM.0000000000002952. [Epub ahead of print].

Because their earlier study (RECOVER) failed to show that an intensive post-ICU, multidisciplinary rehabilitation program improved physical recovery and health-related quality of life (HRQoL),1 Griffith et al hypothesized that pre-ICU health factors may be more important, explaining why some patients may be refractory to their intervention.

This was a cohort study nested within the RECOVER randomized, controlled trial, which enrolled 240 adult ICU survivors who required > 48 hours of continuous mechanical ventilation. The authors aimed to describe the cohort trajectory of HRQoL between three and 12 months and explore the factors associated with HRQoL and patient-reported symptoms at six and 12 months post-ICU discharge. HRQoL was assessed via the Medical Outcomes Study Short Form-12 Version 2 (SF12v2), which included the Physical Component Score (PCS; range, 0-100) and Mental Component Score (MCS; range, 0-100), with higher scores better. The authors predefined a minimum clinical important difference (MCID) in PCS and MCS as greater than ± 5 points. Patient-reported symptoms of appetite, fatigue, pain, joint stiffness, and breathlessness were measured on a visual analogue scale ranging from 0 (no symptoms at all) to 10 (worst symptoms imaginable).

Overall, mean PCS and MCS were reduced compared to population norms, with mean PCS increasing by a statistically significant, but small (less than the MCID), amount between three and 12 months (mean difference, 2.3; 95% confidence interval [CI], 0.6-3.9; P = 0.006); the mean MCS did not change over that same time. Of the 147 patients who had complete PCS and MCS data at three and 12 months, 94 demonstrated no significant clinical improvement in PCS and 101 exhibited no significant clinical improvement in MCS. In the multivariable analysis, higher pre-existing comorbidity burden was associated with worse PCS (beta, -1.56; 95% CI, -2.44 to -0.68; P = 0.001) and MCS (beta, -1.45; 95% CI, -2.37 to -0.53; P = 0.002) at six months in addition to 12 months; critical illness-related variables were not associated with either PCS or MCS at either point. As the number of pre-ICU comorbidities increased, both PCS and MCS tended to be lower after discharge and exhibited a flatter trajectory, reflecting lack of improvement. A higher pre-ICU comorbidity count also was associated with worse patient-reported symptom scores.


This secondary analysis of the RECOVER trial is a helpful addition to our growing understanding of the complex interplay between pre-existing disease and acute critical illness in ICU survivors. Although the RECOVER cohort experienced notably severe critical care stays (APACHE II mean score, 20 [standard deviation {SD}, 8], mean ventilation days 12 [SD, 11], 74% required vasopressors, 27% required renal replacement therapy), pre-ICU comorbidity count was associated most strongly with post-ICU HRQoL and persistent symptoms. These findings support previous studies that have found strong associations between pre-hospital comorbid conditions and 30-day readmissions after hospitalization for sepsis.2-5

Based on these data, a pre-ICU health trajectory is highly significant in determining the post-discharge course, not only regarding healthcare use, but also HRQoL and patient-perceived symptoms. This carries important implications for future intervention studies seeking to improve HRQoL or functional recovery. Patients with more comorbid conditions at baseline may have limited to no improvement and may mask significant effects in other patient subpopulations if not defined appropriately at the outset. This patient population also may require additional resources and/or different interventions to demonstrate improved outcomes. In an age of personalized medicine regarding genetics, biomarkers, and drug response, we should not be surprised that a one-size-fits-all approach to post-ICU care will not suffice.


  1. Walsh TS, et al. Increased hospital-based physical rehabilitation and information provision after intensive care unit discharge: The RECOVER Randomized Clinical Trial. JAMA Intern Med 2015;175:901-910.
  2. Liu V, et al. Hospital readmission and healthcare utilization following sepsis in community settings. J Hosp Med 2014;9:502-507.
  3. Ortego A, et al. Hospital-based acute care use in survivors of septic shock. Crit Care Med 2015;43:729-737.
  4. Goodwin AJ, et al. Frequency, cost and risk factors for readmissions among severe sepsis survivors. Crit Care Med 2015;43:738-746.
  5. Chang DW, et al. Rehospitalizations following sepsis: Common and costly. Crit Care Med 2015;43:2085-2093.