By Eleanor McDermid
A large study shows that nearly a third of patients who survive an intracerebral haemorrhage (ICH) will go on to develop dementia within 4 years.
"Our findings are of immediate clinical relevance in the management of intracerebral haemorrhage survivors and will allow patients and caregivers to be adequately informed about the risk of cognitive decline, and will contribute to tailor preventive strategies", say Charlotte Cordonnier (Université Lille, France) and study co-authors.
They found that the high risk of dementia was partly explained by damage from the haemorrhage itself. Of 218 patients without pre-existing dementia who survived for at least 6 months after ICH, 31 (14.2%) had already developed dementia by that follow-up point.
Furthermore, having a bleed in a lobar location, with consequences for cortical functions and cognition, more than doubled patients' risk of new-onset dementia within 4 years. Older age, stroke severity, previous stroke or transient ischaemic attack, having severe leukoaraiosis and recurrent stroke during follow-up also contributed to the likelihood of new-onset dementia.
However, the dementia rate continued to climb, to reach 28.3% at 4 years, with the rate over this period being "almost identical" among patients with lobar and nonlobar haemorrhage, suggesting that "a hypothesis of a more extensive ongoing vascular or degenerative process triggered by the intracerebral haemorrhage" might be a better explanation for the later dementia cases.
And among the 188 patients well enough to have a magnetic resonance image scan at 6 months, the presence of disseminated superficial siderosis - indicative of underlying cerebral amyloid angiopathy - increased the risk of new-onset dementia 7.45-fold.
Supporting this, each 1-point increase in cortical atrophy score raised the dementia risk 2.61-fold and having more than five cerebral microbleeds raised the risk 2.33-fold.
"Thus, prevention of the macro-event may not be sufficient to prevent dementia, which underlines the need to promote closer collaboration between memory centres and stroke units to identify patients at high risk of developing dementia", the researchers write in The Lancet Neurology.
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Lancet Neurol 2016; Advance online publication