Items analysis of the Frailty Index (FI-35): Insight in the contribution of each item to the level of frailty

Abstract

Background The FI-35 is a valid multidimensional Chinese frailty assessment instrument. Like other scales, functional measures rely on the information the total score provides. Our research aimed to analyze the contribution of each item. Methods Descriptive statistics were used to summarize the sample characteristics. The expected item score (EIS) was used to determine how the items contribute to the generic measure of frailty. Results This study showed that most of the EIS curves increased across the entire range of frailty levels, and most of the items discriminate relatively well over the entire frailty range. Items differentially contributed to the total frailty score and differentially discriminated between frailty levels. Conclusions Although nearly all items monotonically increased with frailty levels, there were large differences between items in their ability to differentiate between persons being either weakly, moderately or highly frail.

Frailty

“…13 A study conducted in China also found that slowness was the most frequent frailty criterion. 16 However, the study conducted by Fried and collaborators 6 found a greater frequency for low physical activity level, followed by slowness, which is in agreement with data described in a study developed in Taiwan. 14 Despite variations in the literature, the results point to issues related to physical aspects, underscoring the need for greater attention to be given to physical activity and body composition in older people.…”

“…The frequency of frailty criteria varies considerably among studies depending on the characteristics of the population studied, methods employed and cutoff points adopted. [13][14][15][16] The most frequent criteria in the present study were slowness and fatigue. The same criteria were the most frequent in a Brazilian study on cutoff points for frailty status.…”

“…Gait speed is a well-established consistent predictor of disability, cognitive impairment, institutionalization, falls and mortality and is a useful, sensitive criterion for identifying the progression of frailty; it can even be used as a single-item assessment tool in clinical practice, considered to be a fast, safe, inexpensive, highly reliable instrument. 16,17 Fatigue was the second most frequent criterion in this study. Pre-frail individuals with fatigue were 1.81-fold more likely to become frail.…”

“…However, divergent results are found among studies with regards to this criterion. 15,16 Such divergences may be due to the subjectivity of the criterion, which is one of its major limitations, as there is no exact measure for quantifying fatigue. Nonetheless, there is strong evidence of its association with depressive symptoms, which, in turn, are associated with frailty.…”

“…Previous studies with community-dwelling older people found this criterion to be one of the most frequent and with a greater power of prediction for frailty syndrome. 15,16,20 In our study, we opted to use a questionnaire validated in Brazil for the measurement of physical activity level, 12 as this instrument addresses activities that are more common in Brazilian culture and therefore better reflects the situation of Brazilian older people. It is well established in the literature that a sedentary lifestyle exerts an influence on the reduction in the quantity and quality of muscle mass and, consequently, contributes to dysfunctionality in the older population, resulting in the emergence of frailty syndrome.…”