An alternative method for Frailty Index cut-off points to define frailty categories

Abstract

Purpose the Frailty Index (FI) is a popular operationalization of frailty. FI cut-off points have been proposed to define, regardless of age, frailty categories with increasing risk. Here, an alternative method is described that takes age into account. Subjects and methods 29,905 participants aged ≥ 50 from the first wave of the Survey of Health, Ageing and Retirement in Europe. The mean follow-up for mortality was 2.4 years. Curve estimation procedures were carried out between age and a FI, and 50% Confidence Intervals (CI) for the regression mean were derived. As opposed to the usual method (FI ≤ 0.08: non-frail; FI ≥ 0.25: frail; rest: pre-frail), the alternative method defines as ‘fit for their age’ those with a FI below the lower 50% CI; ‘frail for their age’ those with a FI above the upper 50% CI; the rest as ‘average for their age’. Using both methods, the prevalence of the frailty categories and their associated mortality rates were compared for each age group. Results The best fit between age the FI was by cubic regression (R2 = 0.174, P < 0.001). Among those in their 50s, 5% were frail by the usual method (mortality: 5%) and 14% by the alternative (mortality: 2%). Among those in their 90s, 64% were frail by the usual method (mortality: 43%) and 41% by the alternative (mortality: 48%). Conclusion the alternative method may be more sensitive in younger ages and more specific in older ages. This may have implications for population screening.

Frailty and Mortality Outcomes in Cognitively Normal Older People: Sex Differences in a Population‐Based Study

“…Some deficits, namely the psychological variables and ADL deficits, had a low frequency in the selected cohort, thus contributing little to the index overall, but it was decided to retain them to maintain consistency within the index for its future application to cognitively impaired participants in the cohort in whom these variables become more prevalent. Also, use of the Frailty Index cut‐points may not be relevant to this population; evaluating age‐specific reference ranges may be more appropriate for future studies in which there are more participants across the age ranges that would allow for greater precision . Nevertheless, when further analyses were conducted using quartiles of the Frailty Index in this population, the results were similar.…”

Frail Elders in an Urban District Setting in Malaysia

“…We do know that there is an association between age and FI, in that it is increased in older age groups, but because the variance explained by age is small, it is debatable if categorizing frailty accounting for age will make a difference. 34 The prevalence of frailty in this study was 5.7%, and 61.8% of the respondents were prefrail. The National Health and Nutritional Examination Survey (NHANES) reported that there were 30% of frail elders and 34% in the vulnerable category.…”

A Frailty Instrument for primary care for those aged 75 years or more: findings from the Survey of Health, Ageing and Retirement in Europe, a longitudinal population-based cohort study (SHARE-FI75+)

“… 74 In addition, an age-adjusted method for frailty screening may be more sensitive in younger ages and more specific in older ages, benefiting the purpose of population screening. 75 The continuous, age-adjusted SHARE-FI75+ score values range from 0 to 1, making it a much more intuitive score than the age-unadjusted one given by SHARE-FI (−4 to 6). 32 …”