The prevalence of frailty among acute stroke patients, and evaluation of method of assessment.

We aimed to determine prevalence of pre-stroke frailty in acute stroke and describe validity of a Frailty Index-based assessment. Cross-sectional. Single UK urban teaching hospital. Consecutive acute stroke unit admissions, recruited in four waves (May 2016-August 2018). We performed the assessments within first week and attempted to include all admissions. Our primary measure was a Frailty Index, based on cumulative disorders. A proportion of participants were also assessed with the 'Frail non-disabled' questionnaire. We evaluated concurrent validity of Frailty Index against variables associated with frailty in non-stroke populations. We described predictive validity of Frailty Index for stroke severity and delirium. We described convergent validity, quantifying agreement between frailty assessments and a measure of pre-stroke disability (modified Rankin Scale) using kappa statistics and correlations. We included 546 patients. A Frailty Index-defined frailty syndrome was observed in 427 of 545 patients (78%), of whom, 151 (28%) had frank frailty and 276 (51%) were pre-frail. Phenotypic frailty was observed in 72 of 258 patients (28%). We demonstrated concurrent validity via significant associations with all variables (all Frailty is present in around one in four patients with acute stroke; if pre-frailty is included, then a frailty syndrome is seen in three out of four patients. The Frailty Index is a valid measure of frailty in stroke; however, there is little agreement between this scale and other measurements of frailty.