The adverse impact of type 2 diabetes on brain volume in heart failure.

OBJECTIVE: Heart failure (HF) is associated with structural brain abnormalities, including atrophy in multiple brain regions. Type 2 diabetes mellitus (T2DM) is a prevalent comorbid condition in HF and is associated with abnormalities on neuroimaging in other medical and elderly samples. The current study examined whether comorbid T2DM exacerbates brain atrophy in older adults with HF.

METHODS: Seventy-five older adults with HF underwent an echocardiogram and completed a brief cognitive test battery. Participants then underwent brain magnetic resonance imaging (MRI) to quantify total brain volumes, cortical lobar volumes, and white matter hyperintensities (WMH).

RESULTS: Approximately 30% of HF patients had a comorbid T2DM diagnosis. A series of multivariate analyses of covariance (MANCOVAs) adjusting for medical and demographic characteristics and intracranial volume showed that HF patients with T2DM had smaller total brain, gray matter, and subcortical gray matter volume than those without such history. No between-group differences emerged for WMH. Persons with T2DM also had smaller cortical lobar volumes, including in frontal, temporal, and parietal lobes. Follow-up analyses revealed that smaller total and cortical lobar brain volumes and WMH were associated with poorer performance on measures of global cognitive status, attention, executive functions, and memory.

CONCLUSIONS: T2DM is associated with smaller total and cortical lobar brain volumes in patients with HF, and these structural brain indices were associated with cognitive test performance. Prospective studies that directly monitor glucose levels are needed to confirm our findings and clarify the mechanisms by which T2DM adversely impacts brain atrophy in this population.