HOUSTON—Hemorrhagic stroke sharply increases the risk of new-onset depression which, in turn, is associated with a 30% increased risk of dementia within five years, according to research presented at the International Stroke Conference 2017.
Alessandro Biffi, MD
“This is of great importance from a research and clinical standpoint, as it may represent a marker of ongoing cognitive deterioration,” said Dr. Biffi.
Hemorrhagic Stroke and Mood Disorders
Previous studies have found that patients with ICH have a significantly increased risk of mood disorders and cognitive decline. “There is probably a link between mood disorders and cognition after ICH, as is the case for a number of other neurologic conditions,” said Dr. Biffi. “Cerebrovascular small-vessel disease is likely to be involved in the underlying pathogenesis for these disorders, as it is also a risk factor for late-life depression in the general population. Therefore, depression and dementia after ICH may share some etiologic connections.”
Dr. Biffi and his colleagues enrolled 695 patients with ICH into their study and followed them for a mean of five years. None of the subjects had ever been diagnosed with a mood disorder or cognitive decline. The researchers conducted telephone interviews with patients every six months.
At baseline, investigators collected CT and MRI imaging data, epidemiologic exposure data, and apolipoprotein E4 genotype. The outcomes were new-onset depression and incident dementia.
Subjects had a mean age of 74 at baseline. In addition, approximately 70% of patients had hypertension, and 15% had heart disease. Less than 1% of the cohort was positive for the APOE e4 gene. Imaging-confirmed white matter disease was present in 65% of participants. During the follow-up period, new-onset depression developed in 278 (40%) patients. The temporal incidence of this outcome was consistent at about 7% per year.
Factors That Influenced Risk of Dementia
Researchers discovered that having more than a single copy of the APOE e4 allele at baseline (hazard ratio [HR], 1.7) and the presence of white matter disease at baseline (HR, 1.82), were significantly associated with new-onset depression. Having had at least 10 years of school protected against depression (HR, 0.75), as did functional independence (HR, 0.52). By the end of the follow-up period, dementia had developed in 80% of individuals with depression (220). In 81% of cases, depression preceded dementia, with an average time lag of 1.5 years, said Dr. Biffi.
In a multivariate analysis, several factors were significantly associated with incident dementia. Higher education reduced the risk by 40% (HR, 0.60). Factors that increased the risk of dementia were black race (HR, 1.48), APOE e4 gene (HR, 2.12), white matter disease (HR, 1.7), and poststroke new-onset depression (HR, 1.29). The study shows only association, said Dr. Biffi. “No causal relationship can be inferred by this study. We also cannot capture the severity of the mood symptoms, and we are unable to examine the relationship between cognition and apathy, which is another highly relevant neuropsychiatric manifestation of small-vessel disease,” he said.
—Michelle G. Sullivan