The effect of severity of white matter hyperintensities on loss of functional independency in patients with mild cognitive impairment: A CREDOS-LTCI (clinical research center for dementia of South Korea-long term card insurance) study

Abstract

OBJECTIVE:

By combining data from the Clinical Research Center for Dementia of South Korea(CREDOS) study and long-term care insurance(LTCI), we aimed to assess whether the severity of white matter hyperintensity(WMH) predicted functional decline in cases of amnestic mild cognitive impairment(MCI).

METHODS:

WMH was evaluated in 3,569 patients with amnestic MCI using the visual rating scale developed for the CREDOS study. The participants were classified as having amnestic MCI with minimal WMH change(aMCI), with moderate WMH change(maMCI) and with severe WMH change(saMCI) according to the severity of the WMH measurements. A Kaplan-Meier survival probability estimate was used to compute median time from the diagnosis of MCI to LTCI enrollment for the three MCI groups. The effect of various risk factors of LTCI enrollment was evaluated using Cox's proportional hazards model, adjusted for covariates.

RESULTS:

As compared with aMCI cases, maMCI and saMCI patients required help with daily activities of living at a younger age. The saMCI and maMCI patients had higher risk of LTCI enrollment as compared with that of the aMCI patients. Younger patients(≤ 65y) with MCI had a 3.201 times higher risk of early LTCI enrollment than older patients(> 65y) did. High clinical dementia rating score and female sex were also risk factors of early LTCI enrollment.

CONCLUSIONS:

WMH predicted the rate of global functional decline and loss of independence in patients with MCI. The findings support the use of neuroimaging of WMH, in conjunction with biomarkers, as a tool in predicting functional decline in patients with MCI.