Association between white matter alterations on diffusion tensor imaging and incidence of frailty in older adults with cardiometabolic diseases

Abstract

Diffusion tensor imaging (DTI) can be used for the early detection of abnormal changes in the integrity of cerebral white matter tracts, and we have previously reported that these changes are associated with indices of early atherosclerotic lesions. Although these changes have been demonstrated to be associated with the incidence of frailty in older adults, no studies have investigated this relationship in patients at high risk for vascular disease. In this longitudinal study, we followed outpatients with cardiometabolic diseases for a maximum of 6 years (median, 3 years) and evaluated the association of baseline DTI data of seven white matter tracts with the incidence of frailty. The modified version of the Cardiovascular Health Study criteria and the Kihon Checklist were used as indices of frailty; fractional anisotropy (FA) and mean diffusivity (MD) were used as indices of white matter changes. Patients who developed frailty based on both indices had low FA and high MD in many of the tracts tested, with the most significant difference found in the MD of the anterior thalamic radiation (ATR). Cox proportional hazard model analysis revealed a significantly high risk of frailty defined by both indices in the groups with high MD values in the left ATR. Similar results were found in patients with diabetes mellitus but not in those without diabetes mellitus. Therefore, abnormalities in the integrity of the left ATR could be associated with the progression of frailty in older adults with cardiometabolic disease, particularly those with diabetes mellitus.

Keywords: diabetes mellitus; diffusion tensor imaging; frailty; older adults; white matter alteration.

Figure 1

Kaplan–Meiercurves of frailty-free survival. The patients were categorized into two groups based on frailty defined using the mCHS or KCL and based on the cutoff MD values of the left ATR. High MD group: MD ≥ 7.8 × 10⁻⁴, low MD group: MD < 7.8 × 10⁻⁴. mCHS, modified Cardiovascular Health Study criteria; KCL, Kihon Checklist; lATR, left anterior thalamic radiation; MD, mean diffusivity; rATR, right anterior thalamic radiation.