Background: Frailty, one of serious global health problems in the elderly, is a growing concern in patients with Alzheimer's disease (AD) because of its high prevalence in AD and its impact on the prognosis.
Objective: To investigate the quantitative association between white matter hyperintensities (WMH) and frailty in AD.
Methods: A total of 144 outpatients were included. All subjects were evaluated by using Korean version of the CERAD assessment battery and diagnosed very mild to moderate AD. WMH volume was calculated using automated segmentation analysis from the 3D MRI image and further partitioned according to the distance from the ventricular surface. Using the Korean Frailty Index, prefrailty was defined by the scores of 3 and 4 and frailty by the score of 5 and higher.
Results: In total, 23.6%were frailty, 32.6%were pre-frailty, and 43.8%were classified as a robust group. The frailty group had higher WMH volume compared to the robust group (p = 0.02), and these trends remained significant after linear regression analyses. According to the subclassification of WMH, using the robust group as a reference, total WMH (OR = 6.297, p = 0.013, 95%CI = 1.463-27.114), juxtaventricular WMH (OR = 12.955, p = 0.014, 95%CI = 1.687-99.509), and periventricular WMH (OR = 3.382, p = 0.025, 95%CI = 1.163-9.8531) volumes were associated with frailty, but deep WMH volume was not.
Conclusions: A quarter of patients with very mild to moderate AD is suffering from frailty. Our study provides the evidence of a cross-sectional relationship between WMH volume and frailty, and there is a difference in the association between the subclassification of WMH volume and frailty.
Keywords: Alzheimer’s disease; frailty; magnetic resonance imaging; white matter hyperintensities.