title: Comparative assessment of two frailty instruments for risk-stratification in elderly surgical patients: study protocol for a prospective cohort study.
abstract: Frailty is an aggregate expression of susceptibility to poor outcomes, owing to age-, and disease-related deficits that accumulate within multiple domains. Older patients who are frail before surgery are at an increased risk of morbidity and mortality, and use a disproportionately high amount of healthcare resources. While frailty is now a well-established risk factor for adverse postoperative outcomes, the perioperative literature lacks studies that: 1) compare the predictive accuracy of different frailty instruments; 2) consider the impact of frailty on patient-reported outcome measures; and 3) consider the acceptability and feasibility of using frailty instruments in clinical practice.
  
  
  
  We will conduct a multicenter prospective cohort study comparing the predictive accuracy of the modified Fried Index (mFI) with the Clinical Frailty Scale (CFS) among consenting patients aged 65 years and older having elective major non-cardiac surgery. The primary outcome will be disability free survival at 90 days after surgery, a patient-reported outcome measure. Secondary outcomes will include complications, length of stay, discharge disposition, readmission and total health system costs. We will compare the accuracy of frailty instruments using the relative true positive rate and relative false positive rate. These measures can be interpreted as the relative difference in the probability of one instrument identifying a true case of death or new disability compared to another instrument, or the relative difference in the probability of one instrument identifying a false case of death or new disability, respectively. We will also assess the acceptability and feasibility of each instrument.
  
  
  
  Frailty is an important prognostic factor in the growing population of older patients having surgery. This study will provide novel findings regarding the choice of an accurate, clinically useable frailty instrument in predicting patient reported outcomes, as well as morbidity, mortality and resource use. These findings will inform current practice and future research.
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Ottawa, Ottawa, Canada. dmcisaac@toh.on.ca.|Ottawa Hospital Research Institute, Ottawa, Canada. dmcisaac@toh.on.ca.|Department of Anesthesiology, The Ottawa Hospital, Ottawa, Canada. dmcisaac@toh.on.ca.
authors.forename: Daniel I
authors.initials: DI
authors.lastname: McIsaac
authors.affiliation: Department of Anesthesiology, The Ottawa Hospital, Ottawa, Canada.|School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Taljaard
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Ottawa, Ottawa, Canada.|Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Bryson
authors.affiliation: University of Ottawa and The Ottawa Hospital, Ottawa, Canada.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Beaule
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Ottawa, Ottawa, Canada.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Gagne
authors.affiliation: Anesthesiology Resident, University of Ottawa, Ottawa, Canada.
authors.forename: Gavin
authors.initials: G
authors.lastname: Hamilton
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: Emily
authors.initials: E
authors.lastname: Hladkowicz
authors.affiliation: Geriatric Medicine, The Ottawa Hospital, Ottawa, Canada.
authors.forename: Allen
authors.initials: A
authors.lastname: Huang
authors.affiliation: Hôpital Montfort, Ottawa, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Joanisse
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.|Division of Urology, University of Ottawa, Ottawa, Canada.
authors.forename: Luke T
authors.initials: LT
authors.lastname: Lavallée
authors.affiliation: Division of General Surgery, University of Ottawa, Ottawa, Canada.
authors.forename: Hussein
authors.initials: H
authors.lastname: Moloo
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.|School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Canada.|Institute for Clinical Evaluative Sciences, Toronto, Canada.
authors.forename: Kednapa
authors.initials: K
authors.lastname: Thavorn
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.|Institute for Clinical Evaluative Sciences, Toronto, Canada.|Medicine and Epidemiology, University of Ottawa, Ottawa, Canada.
authors.forename: Carl
authors.initials: C
authors.lastname: van Walraven
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Ottawa, Ottawa, Canada.
authors.forename: Homer
authors.initials: H
authors.lastname: Yang
authors.affiliation: Ottawa Hospital Research Institute, Ottawa, Canada.|Department of Medicine, University of Ottawa, Ottawa, Canada.|The Ottawa Hospital, Ottawa, Canada.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Forster
mesh_terms: D000368:Aged; D015331:Cohort Studies; D004185:Disability Evaluation; D005189:False Positive Reactions; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D000071066:Patient Reported Outcome Measures; D011183:Postoperative Complications / Q000453:epidemiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D016019:Survival Analysis
keywords: Disability; Epidemiology; Frailty; Geriatrics; Outcomes; Patient reported outcome measures; Prognosis; Surgery