Outcomes Related to Frailty in Older Patients Referred for Cardiac Surgery

• Author / Creator

  Montgomery, Carmel L.

• Objective
  A substantial proportion of patients admitted to intensive care units (ICU) are frail; however, its epidemiology at a population-level has not been explored. Following implementation of a validated frailty measure into a provincial ICU clinical information system, we sought to retrospectively describe the population-based prevalence, correlates and outcomes associated with frailty in patients admitted to ICU.
  A second, prospective cohort study investigated patients referred for cardiac surgery in Alberta, all of whom are admitted to ICU after surgery. A provincial perspective was of interest, in order to establish a baseline description of the relationship between frailty and the clinical and cost outcomes associated with cardiac surgery.

  Methods
  Data were captured using multiple data sources. eCritical Alberta informed a retrospective cohort study of all Alberta adult ICU admissions January 2016 through June 2017, using the Clinical Frailty Scale (CFS) score assigned by admitting physicians to measure frailty (CFS ≥5).
  A further prospective cohort study focussed on patients ≥50 years of age referred for non-emergent cardiac surgery in Alberta November 2011 through March 2014. Patients were assessed pre-operatively for frailty (CFS ≥5) and data were captured on socio-demographics, baseline functional status, comorbid disease and health-related quality-of-life (HRQL). Postoperatively, patients were followed to assess CFS, health services use, vital status and HRQL (EuroQol-5-Dimension-3-Level) allowing for assessment of quality adjusted life years (QALYs). Public payer costs attributable to frailty were calculated in a propensity score matched difference-in-difference (DID) model comparing annual health services costs post-surgery to one-year pre-surgery. Exposure was defined as CFS score ≥5. Primary outcomes were hospital mortality; health services duration and intensity; attributable cost of frailty.

  Results
  In general ICU admissions across the province 15,238 (81%) patients were assigned a CFS score at ICU admission. Of these, 28% (95% CI, 27-28%) were frail. Compared to non-frail patients, frail patients were older (mean [SD] 63[15] vs. 56[17] years, p<0.001), more likely male (54% vs. 46%, p<0.001), had higher APACHE II scores (22[8] vs. 17[8], p<0.001), received less mechanical ventilation (62% vs. 68%, p<0.001) and vasoactive therapy (24% vs. 57%, p<0.001); but more non-invasive ventilation (22% vs. 9%, p<0.001). Frail patients had greater hospital mortality (23% vs. 9%; adjusted-OR, 1.80; 1.64-2.05), longer ICU (4[2-8] vs. 3[2-6] days, p<0.001) and hospital stay (16[8-36] vs. 10[5-20] days, p<0.001) compared to non-frail patients.
  In the cardiac surgery cohort (n=529) mean (SD) age was 67 (9) years, 26% were female, and the prevalence of frailty was 10% (n=51; 95% CI, 7%-13%) with median (IQR) CFS 3 (3–4). Compared to nonfrail patients, those with frailty were older (73[9] vs. 67[9], p<0.001), more frequently female (51% vs. 23%, p<0.001), received valve surgery (76% vs. 57%, p=0.01), and had higher median (IQR) EuroSCORE (8[6–9] vs. 5[3–7], p<0.001). Pre-operatively, frail patients were more likely to require help walking (43% vs. 5%, p<0.001) and report recent falls (35% vs. 11%, p<0.001). Post-operatively frail patients had longer median (IQR) duration of stay in ICU (3[1–5] vs. 1[1–3] days, p<0.001) and hospital (12[8-25] vs. 7[6-10] days, p<0.001). ICU mortality (4% vs. 0.4%; adjusted-OR, 4.89; 95% CI, 0.60-40.03) and hospital mortality (10% vs. 1%; adjusted-OR, 6.33; 95% CI, 1.15-34.71) were elevated in the frail group.
  Among patient referred for cardiac surgery, median (IQR) health services costs for frail compared to non-frail patients were higher overall ($387,360 [$187,254-$613,684] vs. $178,860 [$136,779-$265,611]; p<0.001), in the first year post-surgery ($200,709 [$146,177-$486,852] vs. $147,730 [$100,674-$177,025]; p<0.001). Fewer QALYs were realized at one year for frail vs. non-frail patients (0.71 [0.57-0.77] vs. 0.82 [0.75-0.86]; p<0.001). The attributable cost of frailty in the first post-operative year was $57,836 (SE $44,104).

  Conclusion
  A validated measure of frailty implemented at the population-level revealed a 28% prevalence of frailty among adult ICU patients and 10% among patients referred for cardiac surgery. Frailty was associated with additional health services duration and intensity as well as greater risk of adverse events. Frailty, along with its associated health services costs and patient reported HRQL may have relevance for prognostic and recovery purposes, to optimally inform patients, caregivers and clinicians about risks associated with critical illness, while cost outcomes may be of specific interest to health services planners and decision makers.

• Subjects / Keywords

  • adult
  • cost comparison
  • frailty
  • critical illness
  • cardiac surgery

• Graduation date

  Spring 2020

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-7xdk-jy80

• License

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