Development and validation of a frailty index based on data routinely collected across multiple domains in NSW hospitals.

Abstract

To develop and validate a frailty index (FI) that covers multiple domains, using routine hospital data. To investigate the FI's validity, after excluding medication-related items (FI-ExMeds), for studies of frailty and polypharmacy. A FI was derived from routine NSW hospital data following standard published guidance. In a development cohort (151 inpatients≥70years), the FI was correlated with the Reported Edmonton Frail Scale (REFS) using Pearson's R. Validity and distribution of FI and FI-ExMeds, and correlation with each other, were evaluated in a validation cohort (999 inpatients≥75years). The mean FI for the development cohort was 0.27 (SD 0.09). The FI showed moderate linear correlation with the REFS (n=148, R=0.52, P<.001). In the validation cohort, mean FI (n=993) and FI-ExMeds (n=990) were both 0.28 (SD 0.11). FI-ExMeds showed high linear correlation with the FI (n=990, R=0.99, P<.001). This multi-domain FI is comparable to REFS, with adequate redundancy to exclude deficits for specific analyses.