Cerebral microbleeds are predictive of mortality in the elderly

To investigate the prognostic value of cerebral microbleeds (CMB) regarding overall, cardiovascular-related, and stroke-related mortality and to investigate possible differences based on a cerebral amyloid angiopathy-type and nonlobar distribution of microbleeds.

We included 435 subjects who were participants from the nested MRI substudy of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). Cox proportional hazard models were applied to estimate the risk of overall, cardiovascular-related, and stroke-related death associated with microbleeds in general and microbleeds with a lobar distribution suggestive of the presence of cerebral amyloid angiopathy. The corresponding Kaplan-Meier survival curves were calculated.

Subjects with >1 CMB had a 6-fold risk of stroke-related death compared to subjects without CMB (hazard ratio, 5.97; 95% CI, 1.60-22.26; P=0.01). The diagnosis of nonlobar microbleeds was associated with >2-fold risk of cardiovascular death compared to subjects without microbleeds (hazard ratio, 2.67; 95% CI, 1.23-5.81; P=0.01). Subjects with probable cerebral amyloid angiopathy-type microbleeds had >7-fold risk of stroke-related death compared to subjects without CMB (hazard ratio, 7.20; 95% CI, 1.44-36.10; P=0.02).

This is the first study investigating the association between microbleeds and risk of overall, cardiovascular-related, and stroke-related mortality in an elderly population. Our findings indicate that the diagnosis of microbleeds is potentially of clinical relevance. Larger studies are needed to expand our observations and to address potential clinical implications and cost-benefits of such a policy.