A crosswalk of commonly used frailty scales

Abstract

Background: Several validated scales have been developed to measure frailty, yet the direct relationship between these measures and their scores remains unknown. To bridge this gap, we created a crosswalk of the most commonly used frailty scales.

Methods: We used data from 7070 community-dwelling older adults who participated in National Health and Aging Trends Study (NHATS) Round 5 to construct a crosswalk among frailty scales. We operationalized the Study of Osteoporotic Fracture Index (SOF), FRAIL Scale, Frailty Phenotype, Clinical Frailty Scale (CFS), Vulnerable Elder Survey-13 (VES-13), Tilburg Frailty Indictor (TFI), Groningen Frailty Indicator (GFI), Edmonton Frailty Scale (EFS), and 40-item Frailty Index (FI). A crosswalk between FI and the frailty scales was created using the equipercentile linking method, a statistical procedure that produces equivalent scoring between scales according to percentile distributions. To demonstrate its validity, we determined the 4-year mortality risk across all scales for low-risk (equivalent to FI <0.20), moderate-risk (FI 0.20 to <0.40), and high-risk (FI ≥0.40) categories.

Results: Using NHATS, the feasibility of calculating frailty scores was at least 90% for all nine scales, with the FI having the highest number of calculable scores. Participants considered frail on FI (cutpoint of 0.25) corresponded to the following scores on each frailty measure: SOF 1.3, FRAIL 1.7, Phenotype 1.7, CFS 5.3, VES-13 5.5, TFI 4.4, GFI 4.8, and EFS 5.8. Conversely, individuals considered frail according to the cutpoint of each frailty measure corresponded to the following FI scores: 0.37 for SOF, 0.40 for FRAIL, 0.42 for Phenotype, 0.21 for CFS, 0.16 for VES-13, 0.28 for TFI, 0.21 for GFI, and 0.37 for EFS. Across frailty scales, the 4-year mortality risks between the same categories were similar in magnitude.

Conclusion: Our results provide clinicians and researchers with a useful tool to directly compare and interpret frailty scores across scales.

Keywords: equipercentile; frailty; linking; relationship.

Figure 1.. Equipercentile Crosswalk from the Frailty Index to Commonly Used Frailty Scales

Frailty index scores and the corresponding scores using other frailty scales are presented as a line graph. The cutpoint of 0.25, which corresponds to the transition between pre-frail and (mildly) frail on the frailty index (FI), is highlighted.

Figure 2.. Equipercentile Crosswalk from Commonly Used Frailty Scales to Frailty Index

(A) Frailty scores of commonly used frailty scales and the corresponding frailty index scores are presented as a line graph. (B) The original scores of commonly used frailty scales and the corresponding score on the frailty index are shown using a bar graph. The bottom of each bar represents the transition point to the next score. The transition point between the green and pink bars represents the cutpoints used by the original scale to identify frail versus non-frail.

Figure 3.. Four-year Mortality Risk by Category Based on Identified Crosswalk Cutpoints

Using the crosswalk, low, moderate, and high-risk categories were created for each frailty scale using scores that corresponded to an FI score of <0.2 (low-risk), ≥0.2 to <0.4 (moderate-risk), and ≥0.4 (high-risk). The corresponding scores are shown in the table legend. The bar graphs show the 4-year mortality risk by category when crosswalk cutpoints are used for each frailty scale. Panel A and panel B show the mortality risk for males and females 75-79 years of age, respectively. Abbreviation: CFS, Clinical Frailty Scale; EFS, Edmonton Frailty Scale; FI, Frailty Index; GFI, Groningen Frailty Indicator; SOF, Study of Osteoporotic Fracture Index; TFI, Tilburg Frailty Indictor; VES-13, Vulnerable Elder Survey-13.

Figure 4.. List of Commonly Used Frailty Scales and Their Characteristics

Characteristics of frailty scales included in the crosswalk are presented. It shows which domains overlap between scales. This table can be helpful when choosing which frailty scale to use.