Do Prestroke Risk Factors Influence Future Stroke and Dementia Risk?

Long-term risks of recurrent stroke and poststroke dementia remain high and are substantially influenced by prestroke risk factors, according to a new study.

“Survival after stroke has improved over the past decades, thanks to thrombolytic therapy, specialized stroke units, and better secondary prevention,” the researchers said. “However, such improved survival may lead to more people having long-term hazards of stroke, such as recurrent stroke and dementia. These long-term risks after stroke are not well documented, nor are the factors that determine this risk. In this regard, risk factors that lead to the initial stroke may also predispose to clinical adverse events after stroke.”
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Within the population-based Rotterdam Study, they determined the long-term risk of recurrent stroke and dementia, and the proportion of recurrent strokes and poststroke dementia cases attributable to prestroke cardiovascular risk factors (ie, the population attributable risk).

The researchers followed the cases of 1237 patients with first-ever stroke and 4928 stroke-free participants, matched on age, sex, examination round, and stroke date (index date), for the occurrence of stroke or dementia. They calculated incidence rates in both groups and estimated the individual and combined population attributable risk of prestroke cardiovascular risk factors for both outcomes.

Beyond 1 year after stroke, patients retained a 3-fold increased risk of recurrent stroke and an almost 2-fold increased risk of dementia compared with people without stroke. In total, 39% of recurrent strokes and 10% of poststroke dementia cases were attributable to prestroke cardiovascular risk factors. They found these percentages to be similar for first-ever stroke and dementia in the matched stroke-free population.

“Patients with stroke remain for a long time at an increased risk of recurrent stroke and dementia,” concluded the researchers, noting their results emphasize the need for optimizing both primary and secondary preventions as well as encourage exploration of other potentially modifiable factors.

—Mike Bederka

Reference:

Portegies MLP, Wolters FJ, Hofman A, et al. Prestroke vascular pathology and the risk of recurrent stroke and poststroke dementia [published online July 14, 2016]. Stroke. doi:10.1161/STROKEAHA.116.014094.