The Range and Reproducibility of the Liver Frailty Index.

The Liver Frailty Index (LFI), composed of 3 performance-based tests (grip strength, chair stands, and balance), is a tool specifically developed in patients with cirrhosis to objectively measure physical function, a critical determinant of health outcomes. We aimed to (1) determine the range of LFI scores in adults with chronic liver disease but without cirrhosis, (2) determine the range of LFI scores in adults without known liver disease, and (3) evaluate reproducibility of the LFI in adults with cirrhosis listed for liver transplantation. Intraclass correlation coefficient (ICC) assessed interrater reliability of the LFI. Included were 91 adults with chronic liver disease, 109 adults without known liver disease, and 166 adults with cirrhosis with median Model for End-Stage Liver Disease-sodium of 16. Median (interquartile range) LFI was 3.6 (3.1-4.1) in adults with cirrhosis, 3.1 (2.5-3.7) in adults with chronic liver disease but not cirrhosis, and 2.7 (2.2-3.2) in adults without liver disease (P < 0.001). Using established LFI cutoffs for robust, prefrail, and frail categories, adults with cirrhosis or chronic liver disease were less likely to be robust (29% versus 53% versus 77%) and more likely to be prefrail (57% versus 42% versus 22%) or frail (14% versus 5% versus 1%) when compared with adults without liver disease (P < 0.001). The LFI had excellent reliability with ICC of 0.93 (95% confidence interval, 0.91-0.95). In conclusion, the LFI has external validity in noncirrhotic populations and is highly reproducible among different raters. This objective assessment tool can be implemented in outpatient clinical practice or research to operationalize the concept of physical frailty.