Frailty and mild behavioral impairment: A longitudinal study of pre‐dementia markers

Abstract

AbstractBackgroundFrailty and mild behavioral impairment (MBI) are non‐cognitive markers of dementia and have been associated with one another cross‐sectionally. Better understanding the association between frailty, MBI, and dementia is necessary to determine whether dementia prognostication could be improved by assessing for both frailty and MBI. This study investigated the longitudinal associations between frailty, MBI, and incident dementia.MethodWe analyzed data from 20,010 dementia‐free older adults from the National Alzheimer’s Coordinating Center. Frailty was operationalized using a previously published 44‐item frailty index (FI). MBI was derived from the Neuropsychiatric Inventory Questionnaire using a published algorithm; participants were classified as MBI+ if MBI symptoms were present for ≥2 consecutive visits. We used Cox proportional hazards regression to model the association between: (1) baseline FI and incident MBI; (2) baseline MBI and the incident severe frailty (FI≥0.20). We also examined whether MBI+ older adults with higher FI were more likely to develop dementia than those with lower FI. All models were adjusted for age, sex, education, and cognitive status (cognitively normal or mild cognitive impairment).ResultParticipant characteristics are described in Table 1. The hazard of developing MBI rose by 45% for every 0.1 increase in FI (adjusted hazard ratio; aHR = 1.45, 95%CI: 1.36‐1.55, p<.001) [Table 2]. Likewise, the hazard of developing severe frailty (FI≥0.20) was 97% greater in MBI+ participants compared to MBI‐ participants (aHR = 1.97, 95%CI: 1.85‐2.10, p<.001). Finally, although MBI alone was associated with incident dementia (aHR = 2.02, 95%CI:1.89‐2.17, p<.001), the hazard developing dementia further rose by 1.17 (95%CI: 1.08‐1.26, p <.001) for every 0.1 increase in FI within a sample of MBI+ participants.ConclusionIn dementia‐free older adults, frailty is associated with the development of MBI. Further, MBI is associated with the development of severe frailty. Understanding these relationships identifies the potential to use frailty screening as an indicator of individuals who could develop MBI, and MBI screening as an indicator of individuals at risk of accumulating more health deficits. Although, MBI alone predicts incident dementia, our findings suggest that including general health measures, i.e., frailty, in modeling may improve dementia prognostication.