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Recovery after critical illness in patients aged 80 years or older

Heyland. Intensive Care Medicine 2015; 41:1911-1920. doi:10.1007/s00134-015-4028-2

Clinical Question

  • In older patients (over 80 years) admitted to Intensive Care Units, what factors are predictive of survival with good health-related quality of life?

Design

  • Prospective cohort study
  • Consecutive sampling
  • Two cohorts for more comprehensive analysis within a pragmatic framework
    • hospital cohort‘ of all eligible patients
    • longitudinal cohort‘ of all patients that could be followed for 12 months
  • Inverse probability weighting method used to extrapolate selected longitudinal cohort back to unselected hospital cohort, to allow for potential biases from selecting patients
  • A priori statistical plan including univariate and multivariate logistical regression analyses
  • Trained research personnel completed comprehensive geriatric assessment questionnaire with family member (included frailty index and other functional assessments)

Setting

  • 22 Canadian Intensive Care Units
  • Dates of recruitment not given

Population

  • Hospital cohort
    • Inclusion: All patients aged over 80 years
    • Exclusion: If ICU stay was less than 24 hours; if already included in longitudinal cohort; if study site had already met their quota
    • 3064 consecutive patients screened, of which 894 included in hospital cohort analysis
      • 167 excluded as less than 24 hour stay in ICU
      • 610 excluded as already in longitudinal cohort
      • 1393 excluded as study site already met quota
  • Longitudinal cohort
    • Inclusion: All patients aged over 80 years with an ICU stay of more than 24 hours
    • Exclusion: non-Canadian residents, no appropriate family / friend for complete data collection
    • 3064 consecutive patients screened, of which 610 included in longitudinal cohort
      • 507 (83%) had full data available

Intervention

  • Baseline characteristics (hospital and longitudinal cohort)
    • Patient characteristics
    • Hospital and ICU outcomes
  • Comprehensive geriatric assessment questionnaire (longitudinal cohort only)
    • In-person assessment by trained research personnel
    • Answers obtained from family or significant friends
    • Baseline considered as “patient’s condition two weeks before hospitalization”
    • Included 43 question Frailty Index
  • Follow up (longitudinal cohort only)
    • Telephone follow-up at 3, 6, 9 and 12 months after enrolment
    • Data collected included survival status and Short Form (SF-36) physical function assessment

Control

  • Outcomes were compared against paired baseline data for each patient
  • For some comparisons, age and sex matched data were obtained from a national Canadian registry

Outcome

  • Baseline characteristics (longitudinal cohort)
    • Mean age: 84 years (range 80-99)
    • Caucasian ethnicity: 90%
    • Admission type was 62% medical vs 14 % surgical elective vs 25% surgical emergency
    • Mean APACHE 2 score: 22 (SD 7; range 7-49)
    • Charlson co-morbidity index: 2 (SD 2; range 0-11)
    • Habitation prior to admission
      • Living at home alone: 27%
      • With family member at home: 39%
      • With someone else: 20%
      • In supervised residence: 10%
      • In nursing home: 4%
    • Frailty Index
      • Fit: 41%
      • Mild: 40%
      • Moderate / severe: 19%
    • Mean Physical Function score: 40 (SD 30) out of 100
  • Primary outcome:
    • longitudinal cohort:
      • Survival to 12 months was 56%
      • Survival and physical recovery was 26 % (95% CI 21–31%)
        • Defined as no more than 10 point drop from baseline SF-36 score
    • hospital cohort:
      • survival to 12 months was estimated at 50%
      • Survival and physical recovery was estimated at 24% (95% CI 18–30%)
  • Secondary outcome:
    • Factors associated with reduced likelihood of physical recovery with statistical significance
      • Increasing age
      • Higher APACHE 2 score
      • Higher Charlson Co-morbidity index
      • Higher Frailty Index
      • Admission diagnosis of stroke
      • Higher baseline physical function score
    • Factors associated with increased likelihood of physical recovery with statistical significance
      • Admission diagnosis of CABG/valve replacement

Authors’ Conclusions

  • Patients over the age of 80 have a low probability of being alive and returning to their previous physical function at 1 year after an ICU admission. Effort should be made to record baseline function and frailty, and further research should investigate how this aids decision making.

Strengths

  • Important and topical clinical question
  • Pragmatic design – authors acknowledge that the selected longitudinal cohort group will have selection bias, and validated statistical methods were used to obtain an accurate estimate for the unselected hospital cohort group
  • Sensitivity analyses – suggested that the estimates obtained were robust, accurate and reliable
  • Good external validity – included medical and surgical patients, with a range of diagnoses, co-morbidities and physiological disturbance from multiple hospitals

Weaknesses

  • Small risk of attrition bias – follow-up complete for 83% of longitudinal cohort
  • Limitations to external validity – majority were white Caucasian, and all from Canada; 12 month recovery of function is very dependent on rehabilitation and social care services, which can differ substantially between countries.
  • Internal validity concerns – the statistics are complicated and difficult to verify; the authors reassure readers that the methods are valid and the impact of the selection bias is easily adjusted for, but the outcomes for the unselected group are still only adjusted estimates
  • Clinical implementation – the comprehensive geriatric assessment required trained research personnel; this is not something that working clinicians can easily repeat for each patient over 80, and certainly not in an emergency to aid decisions; shorter tools need to be validated before frailty and functional assessment can be relied upon clinically

The Bottom Line

  • Patients over 80 years old admitted to ICU for more than 24 hours have a poor recovery profile: 25% return to baseline after a year, 25% are alive but significantly worse than baseline and 50% are dead.
  • These data appear reliable and generalisable to most developed healthcare systems, and this might help guide communication and decision making with patients, families and referring clinicians.

External Links

Metadata

Summary author: @DuncanChambler
Summary date: 18 November 2015
Peer-review editor: @SteveMathieu75

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