Inter-Rater Reliability of the Retrospectively Assigned Clinical Frailty Scale Score in a Geriatric Outreach Population

BACKGROUND: Frailty, a common clinical syndrome in older adults associated with increased risk of poor health outcomes, has been retrospectively calculated in previous publications; however, the reliability of retrospectively assigned frailty scores has not been established. The aim of this study was to see if frailty scores, based on chart review data, agreed with clinician-determined scores based on a comprehensive geriatric assessment. METHODS: Per standard practice, all patients seen by one nurse clinician (JW) from the Southwestern Ontario Regional Geriatric Program, a tertiary care-based outreach service, between August 15, 2013 and December 31, 2015 received a comprehensive geriatric assessment which included the assignment of an interview-based Clinical Frailty Scale score (CFS-I). Subsequently, a medical student researcher (JD), blinded to the CFS-I, assigned each consenting patient a frailty score based on chart review data (CFS-C). The inter-rater reliability of the CFS-I and CFS-C was then determined. RESULTS: Of the 41 consented patients, 39 had both a CFS-I and CFSC score. The median CFS score was 6, indicating patients were moderately frail and required assistance for some basic activities of daily living. Cohen’s kappa coefficient was 0.64, indicating substantial agreement. CONCLUSION: CFS scores can be reliably assigned retrospectively, thereby strengthening the utility of this measure.