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. Conclusion-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. © 2009 American Heart Association, Inc.