MRI Biomarkers of Vascular Damage and Atrophy Predicting Mortality in a Memory Clinic Population

Abstract

BACKGROUND AND PURPOSE: MRI biomarkers play an important role in the diagnostic work-up of dementia, but their prognostic value is less well-understood. We investigated if simple MRI rating scales predict mortality in a memory clinic population. METHODS: We included 1138 consecutive patients attending our memory clinic. Diagnostic categories were: subjective complaints (n=220), mild cognitive impairment (n=160), Alzheimer disease (n=357), vascular dementia (n=46), other dementia (n=136), and other diagnosis (n=219). Baseline MRIs were assessed using visual rating scales for medial temporal lobe atrophy (range, 0-4), global cortical atrophy (range, 0-3), and white matter hyperintensities (range, 0-3). Number of microbleeds and presence of infarcts were recorded. Cox-regression models were used to calculate the risk of mortality. RESULTS: Mean follow-up duration was 2.6 (+/-1.9) years. In unadjusted models, all MRI markers except infarcts predicted mortality. After adjustment for age, sex, and diagnosis, white matter hyperintensities, and microbleeds predicted mortality (white matter hyperintensities: hazard ratio [HR], 1.2; 95% CI, 1.0-1.4; microbleeds: HR, 1.02 95% CI, 1.00-1.03; categorized: HR, 1.5; 95% CI, 1.1-2.0). The predictive effect of global cortical atrophy was restricted to younger subjects (HR, 1.7; 95% CI, 1.2-2.6). An interaction between microbleeds and global cortical atrophy indicated that mortality was especially high in patients with both microbleeds and global cortical atrophy. CONCLUSIONS: Simple MRI biomarkers, in addition to their diagnostic use, have a prognostic value with respect to mortality in a memory clinic population. Microbleeds were the strongest predictor of mortality.