Identifying common characteristics of frailty across seven scales

Objectives: To determine whether commonly used frailty scales exhibit shared characteristics when applied to a representative sample of middle-aged and older Europeans.

Design: Secondary analysis of the Survey of Health, Ageing, and Retirement in Europe (SHARE).

Setting: Eleven European countries.

Participants: Community-dwelling adults (N = 27,527; mean age 65.3 ± 10.5, 55% female).

Measurements: Frailty was assessed using SHARE-operationalized versions of seven frailty scales: Edmonton Frail Scale, FRAIL scale, Groningen Frailty Indicator, frailty phenotype, Tilburg Frailty Indicator, a 70-item frailty index (FI), and a 44-item frailty index based on Comprehensive Geriatric Assessment.

Results: All frailty scales demonstrated right-skewed density distributions. On all scales, frailty scores increased nonlinearly with age, between 1% (FRAIL) and 3.6% (FI) per year on a log scale. Frailty scores on all scales exhibited dose-response relationships with 5-year mortality. On all scales, women had higher frailty scores than men of the same age but demonstrated better survival than did men with the same frailty score. On all scales except the frailty phenotype, 99% of participants had scores below the scale's theoretical maximum.

Conclusion: On each frailty scale, frailty score increased nonlinearly with age, mortality risk increased with frailty score, and women had higher scores than men but demonstrated better survival. Each scale except the frailty phenotype demonstrated an upper limit to frailty below the scale's theoretical maximum. Across commonly used frailty scales, these characteristics are common in nature but differ in magnitude.