Developing a Frailty Index and investigating its psychometric properties using Item Response Theory

Abstract Background The proportion of frail older adults is increasing and expected to further increase in the coming years, both globally Dutch population. This poses a great challenge public health. To determine prevalence frailty population, index (FI) recommended. A FI an accumulation model encompassing health deficits multiple domains. Previous research has shown that can be created out existing surveys, since it flexible instrument, fairly insensitive use specific items. However, this based on scale development using Classical Test Theory, while few studies have investigated psychometric properties their Item Response Theory (IRT). aim study was create Health Monitor 2016, investigate its Methods Forty-two were selected three domains, i.e., physical, psychological, social. Psychometric by IRT for polytomous response categories: Graded Model (GRM). Items evaluated Cronbach's Alpha, Factor Analysis, Point Polyserial Correlations, GRM. Results analyses showed all items demonstrated positive association with scale. five did not fit well From physical domain these body mass about adherence activity guidelines: moderate per week; bone muscle strengthening activities; balance exercises. psychological item sense control over one's own future. Conclusions By IRT, we 37 adequate fitted well, our redundant, indicating does matter which are FI. strong method selection thus creating more concise Frailty Index. Key messages Creating solid Index promising epidemiological For Index, needs careful consideration.